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1. 4 11 4 8 Positioner Adjustments d deuce 4 12 4 9 Track Zero Switch Test 4 14 4 10 Door Open Switch and Mounting Location 4 15 4 11 Drive Mechanism Top Rear 1 4 17 4 12 Pressure Points on lt 1 1 4 17 4 13 Clamp Support Plate 1 4 20 102001A e e rr 10 Oo c1 4 Co r9 Oy OY O OG OY OY FS O LIST OF FIGURES cont Mounting Nut LOCATION sack rot TI Saa Pa he A aEN AWO EA NO SEDIS 6 1 PCBA Mounting DetallS c is ORI Ex XAVIER Rar 6 2 Drive Motor and Belt 11 6 4 Drive Motor Ground Dds cuneo v hae x RA uet uod UR cea 6 5 Head Load Arm owes imiteret RR eR Ce ERES S 6 6 Positioner Mounting Screws and Protection Bracket 6 8 Head Carriage Mounting 11 6 9 Head Load Solenoid Write Protect Switch and Latch or pt ae do Rau ee a kukapa do aoe 6 11 Clamp and Clamp Support Plates vss eU EA ERA RNC UA S SS ca 6 12 Spindle Housing v a oar REN ARA TACNA da FETA 6 13 Index Sector LED Assembly Details 6 15 Platen dod 6 16 Door Open Switch
2. 1201 1 100 1501 4 100 1801 8 2201 0 IOO 6801 3 100 l1002 3 100 1202 9 100 2202 8 100 2702 7 100 4702 5 00 1005 1 IOI 0010 5 IOl 2700 9 lOl 0680 5 105 6191 5 105 1002 2 105 1962 7 105 1741 5 150 2001 1 130 1002 0 30 2002 9 160 1000 1 160 3300 3 161 150 6 161 4701 9 161 2202 0 R 49 50 W5 RI4 44 51 1 4 17 18 19 20 21 65 79 52 53 R23 R1I3 47 48 55 R24 43 R58 74 75 R59 R36 R42 R2 22 32 60 73 76 78 R37 R33 61 68 69 R38 56 57 RI R9 R27 89 40 R28 29 R45 46 62 63 70 72 RI2 16 RI5 64 R54 R66 RIO C13 34 35 36 43 C48 5 TABLE 1 CONT REF DESIGNATION PART NO 162 4702 5 163 2203 4 Cll 163 4703 1 1 2 28 29 163 3304 9 C3 4 22 26 37 39 163 3305 6 C4l 49 163 1006 2 14 15 165 1002 6 C5 THRU 10 12 17 18 21 24 30 33 38 40 44 45 46 47 191 0100 5 190 0240 9 190 1000 8 L6 L3 4 Ll 2 5 200 4446 7 CR7 THRU 20 22 23 26 210 5223 8 CR6 210 5237 8 21 220 4002 6 CR24 3 4 5 24 25 300 4400 2 300 4 402 8 340 O110 7 Q5 400 0000 2 U2 UI0 400 0002 8 U9 UI6 400 0004 4 Ul4 400 0014 3 U8 400 0027 5 UI8 400 0051 5 017 400 0074 7 Ull uI9 400 0123 2 401 0016 6 U 401 0017 4 U20 401 00
3. 15 re 6 18 Receiver Detallsi ea ooo ae aaah eee asas ua wa 6 19 Track Zero Switch 1S i ved rH odds Meee ee eae 6 21 ASSEMBLY DRAWINGS AND SCHEMATICS Single A PCBA Assembly Drawing 100071 Single A PCBA Schematic 100072 Single B PCBA Assembly Drawing 100163 Single B PCBA Schematic 100164 LIST OF TABLES Title Page Specification seses SA ED Y RP yuuuk tu US RU RU SS ESS 1 3 End User Troubleshooting i voses op ee RA ees 1 3 Preventive Maintenance 1 1 8 Interface 5 Pes es bua ee EN SS ERAS EC ps 3 5 Troubleshooting Chart we 5 1 OEM Floppy Disk Drive Parts List 7 1 vi 102001A SECTION I GENERAL INFORMATION 1 1 INTRODUCTION This manual provides maintenance information for the Model 1015 and 1016 series of OEM Floppy Disk Drives manufactured by Micropolis Corporation Canoga Park California The manual provides data to aid in installing and maintaining the equipment 1 2 SCOPE OF MANUAL This manual is primarily directed to service personnel either field service engineers or repair technicians in an OEM repair depot The manual consists of eight sections as follows ij Section I General Information provides introductory information of a general nature This includes a brief description of the drives maintenance phi
4. 470 2N4400 TIP WO REVISIONS DESCRIPTION J is C47 DRIVE MOTOR 6 bm R77 V2 w The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duolicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS QTY CODE PART OR NOMENCLATURE ZONE REQD IDENT IDENTIFYING NO ___ OR DESCRIPTION UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCES ON FRAC DECIMALS ANGLES TIONS X XX XX FINISH ___ APPLICATION DO NOT SCALE DRAWING PARTS LIST MICROPOLIS Cn ROT Gke MATERIAL APPROVED BY ED SINGLE A SIZE CODEIDENT DWG NO SCALE 8 oro 12V 8V REG UNREG GND ME z E 5 7 9 59 O Q Q O ee ee ee J IGV UNREG 12eVv KEY 16V GND 8V UNREG 5V 8V GND C5 C4 C6 THRU CIO C45 3 3 01 3 3 01 TPI The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duolicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS cope NOMENCLATURE REQD IDENT IDENTIFYING NO OR DESCRIPTION PARTS LIST MIRRORS UNLESS OTHERWISE SPECIFIED CONTRACT
5. DIRN DIRN step CASE 68 2w R9 68 V2w RIO 50 The information hereon is the property of MICROPOLIS CORP 4 7 UIO ORATION No portion of this data shail be released disclosed mE used or duolicated for procurement or manufacturing purposes C3 without specific written consent of MICROPOLIS MICROPQLIS i SIZE ICODEIDENT DWG NO 100164 SE sers 93 HDLD SEL PSEN MTRN DOOR DOOR SV RI2 47K RIA 75452 HEAD LOAD lev J4 SOLENOID ACR IN4002 MOT The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duplicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS SIZE CODEIDENT DWG NO SCALE fs SHEET OF 9 OF 9 5V RIS 100 TP2 INDEX LED SECP VIO 5V RIG 1514 514 BLU l INDEX E A TRANSDUCER 470PF GRN 5 O s 1 3 O 4 pr 45V RUNE aa II RNI P xi J 150 7416 YEL 4 3 M A OOR luo DOOR 5 D Pon 150 7416 4l 3 4 NO 5 U2 TRK GRY t 1 WHT 9 5 uz TRK WRT PROT w BRNI l2 W RED 7 uz y I
6. D BY fee ee FINISH u q E SIZE CODE IDENT NO DWG NO NEXT ASSY USED ON _ IOOO72 APPLICATION _ DO NOT SCALE DRAWING _ SCALE _ __ _ _____ 5 UNLESS OTHERWISE SPECIFIED CONTRACT NO DIMENSIONS ARE IN INCHES i TOLERANCES ON FRAC DECIMALS ANGLES TIONS X XX XXX 4 C24 C26 3 3 R49 LI L3 A o 24UH CRIS 27 ISOOPF CRIS B RSO L2 L4 B o M IOOUH 24UH C25 RSI 4700PF 100 tilev lav F NEXT ASSY USED ON REVISIONS DESCRIPTION 5V RD2 13 12 SEL WBSY The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duplicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS QTY CODE PART OR f NOMENCLATURE ZONE REQD IDENT IDENTIFYING NO OR DESCRIPTION PARTS LIST UNLESS OTHERWISE SPECIFIED CONTRACT NO Ir DIMENSIONS ARE IN INCHES MICROPQLIS TOLERANCES ON DR BY aay FRAC DECIMALS ANGLES TONS x 6 ane rm Aule poc FINISH CODE IDENT NO DWG NO L DO NOT SCALE DRAWING _ SCALE sHEET 7 OF 9 MOTOR TACH l2 V c E Po ecc nc sd L6 lO JH ca 1 C38 Cao l C40 3 3 01 3 3 Ol R65 150 CR20 R64 Gad 33 CR2I IN5237B MOT CR24 IN4002 Q5
7. Figure 2 2 Typical Multiple Drive System The interface cable consists of a set of common input output lines and four disk select lines All lines are applied to all drives Address comparison logic in each drive enables the drive to respond to one and only one disk select line Instructions for setting the address comparison logic are given in paragraph 2 7 2 A single drive may be set to respond to address 0 1 2 or 3 normally if there is only one drive it will be set for address 0 In a multi drive system no two drives may be set to respond to the same disk select line In a multi drive system a distinction is made between the master drive and the add on drives The master drive includes a resistor network for terminating the interface lines An add on drive does not contain terminators All 1015 1016 drives are shipped as master drives instructions for converting a master drive to an add on drive are given in paragraph 2 7 2 The master add on distinction does not effect the address selection any drive may have any address 2 6 102001A The following Daisy Chain interface cables are available from Micropolis Hodet Wo Usage 1083 02 Interface Cable B Two drives 1083 03 Interface Cable C Three drives 1083 04 Interface Cable D Four drives The Daisy Chain interface cable is connected in place of the standard Interface Cable A The Master drive the one with the terminators must be co
8. Generate the drive ready RDY status signal D a UC om Initialize the drive motor 3 5 7 1 Switch Debouncers Sh 5 of Dwg 100164 The door open switch track zero switch and write protect switch closures are applied to latched gates U2 2 U2 4 and U2 8 respectively to eliminate the effects of contact bounce 3 5 7 2 Transducer Pulse Shaper Sh 5 of Dwg 100164 The index transducer photo transistor output is applied to Schmitt trigger U10 The output at U10 4 is the sector pulse SECP which in turn is applied to interface driver U1 8 U10 10 provides positive feedback to produce hysteresis thus preventing the circuit from responding to small discontinuities in the input signal 3 5 7 3 Head Load Solenoid Driver Sh 4 of Dwg 100164 The head load solenoid is energized whenever the drive is selected or the HDLD signal is true This latter mode allows the head to remain loaded even when the drive is deselected for example to avoid incurring a head load time in overlap operations such as drive to drive disk copying Whenever the SEL or HDLD signal is low the output of U12 11 goes high This energizes the head load solenoid driver U3 5 if the motor is enabled MTRN low PSEN is high and the drive door is closed DOOR is low 102001A 3 29 3 5 7 4 Drive Ready Signal Sh 4 of Dwg 100164 When the MTRN PSEN and DOOR signals become true a 1 5 delay circuit consisting of U9 2 R12 C7 C8 a
9. If the operating conditions exceed these the preventive maintenance opera tions specified in table 1 3 should be performed 102001A 1 7 TABLE 1 3 PREVENTIVE MAINTENANCE SCHEDULE Time Manual Operation Frequency Required Paragraph i Hours Reference Replace Head 2000 hrs of Load Pad diskette access Clean Head 2000 hrs of diskette access Lubricate Lead 2000 hrs of Screw diskette access Replace Drive 5000 hrs of motor motor operation Lubricate Latch Every two years Mechanism NOTE These maintenance operations are required only when operating conditions exceed normal 1 6 1 Cleaning the Head CAUTION Rough or abrasive cloth must NOT be used to clean the head Use only iso propyl alcohol or DuPont Freon TF use of other solvents such as carbon tetra chloride may damage the head lamination adhesive To gain access to the head it will usually be necessary to first remove the drive from the system enclosure see paragraph 6 2 for procedure Clean the magnetic head with a soft lint free cloth or cotton swab moistened with isopropyl alcohol or DuPont Freon TF Wipe the head carefully to remove all accumulated oxide and dirt Dry the head with a lint free cloth NOTE The head must be cleaned after head load pad replacement 1 8 102001A 102001A 1 6 2 Lead Screw Lubrication To gain access to the lead screw first remove the drive from the system enclosure see paragraph 6 2 and then temp
10. ee eh ruines os 1 10 SECTION II INSTALLATION deb Introductions ham pete ke dd 2 1 Cee Unpacking the yusa as ac dri aca ue AT aa we TOR ECCE we 2 1 2 3 Re packing the Drive for 1 2 2 2 4 Unpacking Re packing Drives with Sleeves 2 2 225 Visual Inspection dus wide EMEN arx Soe Caos aub RN E do ques 2 2 2 6 Installing the OLIV onu wb PE E NERA EAE eee es e P n 2 3 2 6 1 General 1 11 2 3 2 6 2 Specific Mounting Requirements ates 2 3 CaF Multi Urjve DISK 575 uA Im REESE UE A DU EAE RUE Era 2 6 2 7 1 Daisy Chaining 1 2 6 2 7 2 Master to Add on lt 1 0 2 7 2 4133 Address Changing ss see s ale was ee ree rr 2 7 2 8 SUDD YING DG POWON eco Sia Weta 2 8 SECTION III THEORY OF OPERATION Sel ENTVOGUCEION ca ee eames AQ EN ERE ri RUP ad V 3 1 Bee Drive sese ERRARE dx RE aUe ADOOS SAU E e SA 3 1 3 2 1 Spindle Drrve SUyStel rod YI EX RS e S RES 3 2 2 2 64 nead Carrsage Assemb se sera bari ace Ve RR a EUR a 3 2 3 2 3 Positioner Control 15 3 2 In6eDAOOKS kx wr co OR EH a
11. n HEAD LOAD 2 SOLENOID PSEN EEG IN4002 500 LSO4 1502 3 3 2 u3 MTRN 3E us DOOR 2 7 l IOO PF MOT 5V RI2 47K LSO2 I3 12 RIS 3 U8 4 3 RDY The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duolicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS cove PART OR NOMENCLATURE mm REQD IDENT IDENTIFYING No OR DESCRIPTION PARTS LIST N PECIFIED CONTRACT NO MICROPOLIS TOLERANCES ON FRAC DECIMALS DR BY TIONS X XX mE F D SINGLE ee er NEXT ASSY USED ON 72 SCAE O APPLICATION DO NOT SCALE DRAWING SE SHEET 4 OF 9 met CS T 7 pu J3 cry INDEX LED VIO O giu 8 INDEX TRANSDUCER 6 INTERLOCK p MEL OT cal psc e J4 yer ONO DOOR 5 SWITCH 6 6 vio ai ONO TRK SWITCH WRT PROT SWITCH 45V 14 IOO TPS 5V SECP RIS 1514 1514 15108 We u Jus MO q m d m RI6 47K A 45V 17 150 1500 15 d RI8 150 U2 DOOR LSOO RI9 150 500 l ze L 500 WPTSW NEXT ASSY USED ON APPLICATION REVISIONS zone LTR DESCRIPTION 7 DATE APPROVED The infermation hereon is
12. 08 and erase timer current driver U8 for the upper head These components are absent on versions of the PCBA for use with single sided one head drives The head selection levels HSLT and HSLT from Sh 2 are applied to U14 3 and U14 5 to enable respectively the lower or upper head erase drivers and to U22 10 and U22 8 If the lower normal head is selected U22 10 will be low turning on Q4 Q5 in turn will be turned off by HSLT being high Write current from Q3 or read bias from R41 R42 and R43 will therefore be coupled to the correct head Write Control Logic The write control logic provides the necessary signals to gate and control the write circuits The write control logic consists of elements U18 U20 U22 and U24 This logic controls the operation of the write current driver the erase current driver and the write busy WBSY generator The write control signal for these circuits is generated by four external logic signals gated by U18 and U20 When WRT is low TRUE write protect WPTSW is low FALSE and stepper busy SBSY is low FALSE U20 12 is high enabling gate U18 13 If the drive is selected SEL is high and U18 11 goes low This condition is coupled to the base of Q3 via U22 6 generating the write busy WBSY signal As U18 11 goes low exclusive OR gate U24 11 goes high releasing the set and clear direct inputs at pins 10 and 13 of U21 This condition enables U21 to respond to the state of the write d
13. 915 DIMENSIONS INCHES CM Figure 2 1 Drive Mounting Details Sh lof 2 Without Optional Protective Sleeve 2 4 102001 20 8 30 51 21 08 6 32 HOLE FAR SIDE BOTTOM 3 PL MAY BE USED FOR 5 EXTERNAL MOUNTING 5 80 14 73 SLEEVE HOLES 6 32 3 PER SIDE D OUTER 2 SCREWS EACH SIDE CAN BE 12 93 REMOVED AND USED FOR EXTERNAL MOUNTING 1 56 3 12 Go 7 92 Bi 45 85 4 00 2 16 10 16 DRIVE chassis 1 14 SLEEVE ATTACHES TO PLASTIC MOUNTING NUTS 6 32 2 PER SIDE ON DRIVE CHASSIS PREFERRED FOR EXTERNAL MOUNTING USE SUGGESTED PANEL OPENING BOTH FRONT MTG NUTS AND EITHER ONE REAR MTG NUT 5 825 010 py 3 305 010 INCHES 005 005 025 025 DIMENSIONS INCHES 14 795 BY 8 395 95 CM HOS Figure 2 1 Drive Mounting Details Sh 2 of 2 With Optional Protective Sleeve 102001A 2 5 2 7 MULTI DRIVE DISK SYSTEMS Micropolis 1015 1016 drives can be configured into multi drive systems with up to four disk drives This section provides the technical information necessary to implement a multi drive system 2 7 1 Daisy Chaining Drives A multi drive system consists of two three or four drives connected to the host controller with a Daisy Chain interface cable A typical multiple drive system is shown in figure 2 2 DAISY CHAIN INTERFACE CABLE D DISK CONTROLLER BOARD DRIVE 3 DRIVE 2 DRIVE 1 DRIVE 0 ADD ON ADD ON ADD ON MASTER
14. CIRCUMFERENTIAL AZIMUTH ALIGNMENT The circumferential azimuth alignment test checks that a The relationship between the head and the index sector photo transistor is correct b The head moves along a line which passes through the center of the diskette i e is a radius The circumferential azimuth alignment should be checked whenever a The head is replaced b The positioner subassembly is replaced c The platen assembly or photo transistor is replaced d The LED assembly or the LED is replaced e Diskette interchange compatibility problems are encountered 4 8 1 Procedure a Apply power to the drive Apply a low signal to the MTRN interface line J1 pin 16 c Insert an alignment diskette Micropolis P N 641 0590 1 Dysan P N 282 in the drive and load it d Connect the oscilloscope to Single A TP3 and TP2 GND Single B TP5 and TP6 GND Set the vertical scale to 0 5V cm and the time base to 50 usec cm Trigger external positive on the leading edge of the index sector pulse at Single A TP5 Single B TP2 4 7 e Apply interface signals that cause the drive to be selected and positioned at Track 5 for a 100TPI MOD II drive or at Track 1 for a 48TPI MOD I drive j f Measure the time between the leading edge of the index pulse and the first peak of the index alignment burst see figure 4 5 The time should be in the range of 100 to 300 usec Note the value and proceed to step g
15. Figure 4 5 Circumferential Azimuth Alignment Waveform g Apply interface signals that cause the drive to be selected and positioned at Track 76 for a 100TPI MOD II drive or at Track 35 for a 48TPI MOD I drive h Again measure the time between the leading edge of the index pulse and the first peak of the index alignment burst This time and the time noted in step f should differ by no more than 100 usec 1 If the 100 usec difference in step h is exceeded perform the Azimuth Adjustment paragraph 4 8 2 and then the Circumferential Adjustment paragraph 4 8 3 If the difference in step h is 100 usec or less but the time noted in step f is outside the 100 300 usec range perform the Circumferential Adjustment paragraph 4 7 3 only If both steps f and h are satisfactory no adjustment is needed If the bursts cannot be obtained Radial Alignment paragraph 4 9 or the Track Zero Switch Adjustment paragraph 4 10 may be required 4 8 2 Azimuth Adjustment NOTE As the positioner azimuth is adjusted Significant changes of burst amplitude will occur In extreme cases it may be necessary to readjust the radial alignment see paragraph 4 9 to re establish an on track condition 4 8 1020014 a Temporarily install the maintenance standoff at the rear of the drive mechanism so the mechanism does not rest on the step motor b Apply power to the drive c Apply a low signal to the MTRN interface line J1 pin 16 d In
16. Note the routing of the head cable then cut the tie wraps and free the cable from the drive mechanism b Rotate the lead screw until the head carriage is fully forward away from the stepper motor 6 7 c Loosen the screw securing the positioner protection bracket see figure 6 6 and turn the bracket out of the way so the positioner can be removed POSITIONER PROTECTION BRACKET MAINTENANCE STANDOFF Figure 6 6 Positioner Mounting Screws and Protection Bracket d Remove the two positioner mounting screws that attach the positioner mounting block to the chassis e Move the positioner with the head carriage away from the spindle housing until the lead screw clears the spindle housing bearing CAUTION If the original head is going to be installed on the replacement posi tioner be careful to avoid touching the head face f Carefully remove the positioner and head carriage from the drive mechanism 6 8 102001A g Remove the three screws that hold the head carriage spring plate against the lead screw see figure 6 7 Remove the spring plate and the head carriage from the positioner HEAD CARRIAGE I SCREW POSITIONER RETAINING HEAD CARRIAGE MOUNTING RING SPRING PLATE BLOCK Figure 6 7 Head Carriage Mounting Details NOTE For the following step use the replace ment head carriage and or replacement positioner h Install three screws that hold the spring plate against the lead s
17. Read Amplifier Gain 4 6 6 4 DRIVE MOTOR OR DRIVE BELT Depending on how the disk drive is mounted the drive motor and or drive belt may be accessible without first removing the drive If it is necessary to remove the drive follow the procedure given in section 6 2 CAUTION If the drive belt is to be reused do not stretch or kink it during removal If this happens the drive belt must be replaced a Slip the drive belt off the large pulley with the strobe disk and remove it from the drive motor pulley see figure 6 3 Retain the belt if it is acceptable for reuse Note which surface of the belt is in contact with the pulleys If the drive belt is to be replaced and the existing drive motor is acceptable proceed directly to step i 6 3 b BEZEL MOUNTING SCREWS LARGE DRIVE BELT DRIVE MOTOR PULLEY PULLEY Figure 6 3 Drive Motor and Belt Details Disconnect the cable from the drive motor at J4 on the PCBA Clip the tie wraps on the cable Two mounting screws secure the drive motor to the chassis On some drive mechanisms one of these screws secures a ground lug In this case the motor is insulated from the chassis by a plastic disk and two insulating shoulder washers On other drive mechanisms the ground lug is attached by a third screw when removing the drive motor from one of these mechanisms remove this third screw before removing the motor mounting screws 6 4 102001A
18. SINGLE A The information hereon is the property of MICROPOLIS CORP SIZE CODE IDENT NO DWG NO ORATION No portion of this data shall be released disclosed D O O 7 H used or duplicated for procurement or manufacturing purposes 2 without specific written consent of MICROPOLIS _ scate SHEET _ RESERVED HDLD i NTRN DIRN N NY o STEP N Nw WDA cnc lH ud cic uc tud WRT Ww fto RESERVED Q 051 fa 052 puce D o Gl possen DS4 Qi Od UIS 220 330 Q TERM 5 9 L 255 LSO4 LSO4 iD LSO4 DE T5V 1502 D HDLD MTRN DIRN DIRN STEP WDA wRT LSO4 SEL SEL RDY SECP TRKO SBSY WPT SW 7 E e o o PN Ova wos T REVISIONS ZONE LTR DESCRIPTION DATE APPROVED Ji 438 RDY 5 7438 Ze SECP l lo i LSO2 i e us Y 26 1 TRK I l 250 28 7 WPT E A 7416 l BI 9 u bg BO P RDA 7416 29 5 6 9 RD2 07 The information hereon is the property of MICROPOLIS ORATION No portion of this data shall be released disclosed used or duplicated for procurement or manufacturing purposes without specific written consent of MICROPO
19. The information hereon is the property of MICROPOLIS CORP __ L Te MES TR 7416 ORATION No portion of this data shall be released disclosed used or duplicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS 100164 some SETS OFS SEL WRT SBSY 5V 12Vv Q e 5V 6 HSLT CIO ci2 047 Ol HSLT y CRIO 5 O1 RI8 RI9 R25 M 2N4402 NI m 2N4400 R26 CR8 LSK INS223B R20 330 LS00 1527 12 i p gt 7 H 2 NES55 l3 UIS 5 R30 CRIZ 7 4 l2K 2 F s 6 we UB es N4402 C14 CRI IOOPF i CIS 01 12 16 560 R42 T yes Cs 2N4402 2N4402 Nis ies R33 I SK R43 C21 2 2K 01 B R50 330 v2 PSEN R5I IOO R46 1 8K WBSY R47 Ol cre4 MCR25 CR26 R44 R48 12K 27K 12V F R45 R49 27K CR27 B OMIT FOR ice SINGLE HEAD CI9 R36 7 C20 d VERSIONS The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or dupticated for procurement or manufacturing purposes without specific written consent of MICROPOLIS SIZE ICODEIDENT NO DWG NO o scu CY SHEETG or 9 12V F 45V C26 C27 C34 3 3 Ker 01 R65 470 5 R52 A 8 7 CR28 u26 d 9 da
20. and CR5 in conjunction with zener diode CR1 limit the turnoff transient to 20V Referring to figure 3 12 it can be seen that the step sequence is complete at the end of SBSY approximately 23 ms If after a further 12 ms i e a total of 35 ms after a step pulse a further step command has not been received hold driver U5 5 is deenergized via the delay circuit U7 10 U8 6 R3 and C49 A hold current of about half the original value is then supplied via U5 3 and resistors R5 R6 R7 and R8 This scheme allows a system and motor power reduction in the standby mode 3 4 6 Miscellaneous Control Circuits These circuits perform several functions Debounce the drive switch closures Reshape the pulses from the index transducer Control the head load solenoid Generate the drive ready RDY status signal vc ow 3 4 6 1 Switch Debouncers Sh 5 of Dwg 100072 The door open switch and the track zero switch closures are applied to latched gates U2 11 and U2 3 to eliminate the effects of contact bounce 3 4 6 2 Transducer Pulse Shaper Sh 5 of Dwg 100072 The index transducer photo transistor output is applied to Schmitt trigger U8 The output at U8 12 is the sector pulse SECP which in turn is applied to interface driver 01 9 08 10 provides positive feedback to produce hysteresis thus preventing the circuit From responding to small discontinu ities in the input signal 3 4 6 3 Head Load Solenoid Driver Sh 4 of Dwg 100
21. d While holding the drive motor remove the two drive motor mounting screws Retain the plastic disk and shoulder washers if present Remove the drive motor from the chassis e Hold the replacement drive motor and plastic insulator disk if present against the chassis f Install the right side motor mounting screw and shoulder washer if present g If the drive motor ground lug is secured by the left side motor mounting screw run the screw through the ground lug and shoulder washer and install see figure 6 4 If the ground lug is secured by the third screw install the right side motor mounting screw and attach the ground lug to the chassis with the third screw DRIVE MOTOR PULLEY MOTOR MOUNTING INSULATED SHOULDER Tt WASHERS GROUND LUG OPTIONAL Figure 6 4 Drive Motor Ground Lug h Connect the cable from the drive motor to J4 on the PCBA Secure the cable with tie wraps i Place the original or replacement drive belt over the drive motor pulley then rotate the large pulley while slipping the belt over it Ensure that the correct surface of the belt is in contact with the pulleys see step a j Perform the Drive Motor Speed test and adjustment paragraph 4 3 and the Instantaneous Speed Variation test paragraph 4 4 102001A Oe 6 5 HEAD LOAD PAD The head load pad seats into a recess in the head load arm and is held in place with adhesive The head load pad and arm are a
22. g and h are within one major division 1 cm of being equal when the larger lobe is set to five major divisions If the track alignment is not acceptable proceed to step i Loosen the two positioner flange mounting screws that clamp the positioner flange to the spring plate see figure 4 8 POSITIONER FLANGE TO SPRING PLATE MOUNTING SCREWS POSITIONER AZIMUTH CLAMP SCREWS FLANGE Figure 4 8 Positioner Adjustments 102001A Rotate the positioner body as required to equalize the lobes Rotate CW if the first lobe is greater than the second or CCW if the second lobe is greater NOTE If the adjustment range is inadequate to equalize the lobes the track zero switch must be moved one full track See section 4 10 Retighten the positioner flange screws torque to 18 inch lbs Repeat steps g and h observing the read envelope Repeat the adjustment as necessary to obtain equal amplitudes NOTE Sometimes the lobe amplitudes cannot be equalized for conditions of both steps g and h In this case adjust the radial alignment so that the differential between lobes is equal and opposite for steps g and h If under these condi tions the limit of step i is still not met check the Positioner Step Timing section 4 5 and the Positioner Mechanical Adjustment section 4 12 4 10 TRACK ZERO SWITCH AND ZERO STOP The track zero switch indicates to the controller that the head is at track zero The zero stop
23. reduction from motor to spindle When the drive door is closed a spring loaded clamp attached to the receiver assembly lowers and forces the diskette over a precision cone on the spindle assembly The cone profile is such as to provide an interference fit centering the diskette on the spindle Centering is promoted by the rotation of the spindle during the diskette clamping process The door switch is adjusted so the spindle begins to rotate before the diskette is clamped to the spindle 3 2 2 Head Carriage Assembly The head consists of a ferrite read write R W element and two tunnel erase elements mounted in a barium titanate slider The head is mounted ina carriage assembly which is both supported and driven by the lead screw via a Steel follower and is also referenced to the platen When the drive is selected the head load solenoid is energized allowing the load arm and pressure pad to force the diskette into contact with the head with a load of 15 to 18 grams A foam rubber pad on the solenoid arm ensures the diskette jacket is loaded against the platen surface In this way an accurate relationship is established between the diskette and the head surface yielding a controlled penetration When the head load solenoid is deenergized the diskette has little or no contact with the head 3 2 3 Positioner Control Mechanism The head carriage assembly is positioned by a four phase permanent magnet stepper motor via a ground stainless steel
24. 3 7 3 6 Single A Overall Block Diagram 3 8 3 7 Single A Motor Control Circuit Block Diagram 3 9 3 8 Single A Read Circuitry Block Diagram 3 11 3 9 Single A Read 3 12 3 10 Single A Write Circuitry Block Diagram 3 13 3 11 Positioner Control Circuit Block Diagram 3 16 3 12 Positioner Control Circuit Timing Diagram 3 17 3 13 Single B Overall Block Diagram hn 3 19 3 14 Single B Motor Control Circuit Block Diagram 3 21 3 15 Single B Read Circuitry Block Diagram 3 22 3 16 ingle B Read Waveforms ra 3 23 3 17 Single B Write Circuitry Block Diagram 3 24 3 18 Positioner Control Circuit Block Diagram 3 27 3 19 Positioner Control Circuit Timing Diagram 3 28 4 1 Single A PCBA mounted Components 4 2 4 2 Single B PCBA mounted Components 4 2 4 3 ISV Test WdvefOLTI sabes Xt REC XE 4 4 4 4 Positioner Step Timing 4 5 4 5 Circumferential Azimuth Alignment Waveform 4 8 4 6 Drive Adjustment ACCESS over ESO RE COMES h aste Mae RAE eds 4 9 4 7 Cat s Eye Pattern for Radial Alignment
25. 3 of Dwg 100164 The positioner control circuit shown in block diagram form in figure 3 18 generates signals which cause the stepper motor to move the head from track to track in response to a step command Four sequential signals designated phase 1 6 phase 2 2 phase 3 3 and phase 4 4 are applied to the stepper motor drive circuits to cause track to track positioning Initially the system is in the hold state with 4 on If a step in command is received the signal sequence 1 2 3 4 is generated If a step out command is received the signal sequence 3 2 1 4 is generated GATED OSCILLATOR STEP Q WEN SEQUENCER MULTIPLEXER F DRIVERS DIRN DIRN DELAY Figure 3 18 Positioner Control Circuit Block Diagram The positioner control circuit consists of an NE555 timer connected as a gated oscillator U6 a dual and or gate U19 which is used as a multiplexer and three flip flops U13 9 U13 5 and U21 5 which comprise the sequencer Figure 3 19 shows the timing relationships for the positioner control circuit operation STEP CLK aza CEU Nae ONERE i Da l 1 s3 PE NEN ME E 4 gg el UNUM SOUPE EDEN Erb Figure 3 19 Positioner Control Circuit Timing Diagram Initially the oscillator is held clear and the flip flops are reset When a step pulse occurs with the drive selected and not writing a positive going pulse is generated
26. 6 01 8 01 11 and 01 3 and indirectly via 016 12 on Sh 7 of Dwg 100072 for the read data signal The select signal also drives a LED panel indicator via driver U20 4 to indicate that the drive is selected 3 4 2 Motor Control Circuit Sh 8 of Dwg 100072 The motor control circuit is a closed loop servo which controls the spindle drive system The spindle drive consists of a DC motor and AC tachometer mounted on a common shaft The DC motor shaft rotation is converted by the tachometer to an AC signal whose amplitude is proportional to the speed of the motor This feedback signal is rectified and filtered to produce an equivalent DC signal An operational amplifier compares the feedback signal with a reference level generated on the PCBA The net output from the operational amplifier drives a power amplifier which in turn powers the DC motor Figure 3 7 is a block diagram of the motor control circuit DC MOTOR COMPARATOR R66 SPEED ADJUST AC TACHOMETER Figure 3 7 Single A Motor Control Circuit Block Diagram 02001A 3 9 b C Rectifier and Filter The AC tachometer signal enters the Single A PCBA at J4 14 and 15 Diode CR20 and resistor R64 form a half wave rectifier whose output is filtered by capacitor C41 The filtered signal is applied to the next stage through resistor R68 Comparator and Reference Circuit Operational amplifier U6 compares the output of the previous stage with a reference level establis
27. LAST USED NOT USED AND DELETED REF DESIGNATION SEE TABLE FOR COMPONENTS AFFECTED BY VERSION SEE TABLE 410 0311 2 40 ESSA 5 FOR PART NO OF COMPONENTS NOT AFFECTED BY VERSION SEE TABLE I 410 0592 7 4 FOR PCBA SEE DRAWING NO 100163 SIRE 3 ALL DIODES ARE IN4446 622 0001 9 CRI 2 ALL CAPACITOR VALUES ARE IN MICROFARADS C5 6 7 8 163 3305 6 163 1006 2 165 1002 6 C2 12 5 19 20 21 22 27 31 34 41 43 46 50 52 53 54 55 56 The information hereon is the property of MICROPOLIS CORP 190 0240 9 L3 L4 0401 9 J2B le ALL RESISTOR VALUES ARE IN OHMS asia austen Gee as 190 1000 8 680 0503 2 J2A NOTE UNLESS OTHERWISE SPECIFIED without specific written consent of MICROPOLIS 191 0100 5 680 1001 6 75 A isis QTY CODE PART OR NOMENCLATURE 680 1601 3 25 ERER Sues 1 200 4446 7 CR5 11 12 14 15 16 17 18 680 I7O 11 J34 UNLESS OTHERWISE SPECIFIED CONTRACT NO DIMENSIONS ARE IN INCHES TOLERANCES ON FRAC DECIMALS ANGLES TIONS X X XX x 29 30 55 CRB CR3I CR2 CR3 4 5 6 7 34 680 1603 9 017 684 0001 9 WI 2 5 4 MICROPOLIS CHK SCHEMATIC 210 5225 8 210 5235 2 210 5237 8 220 4002 6 684 0003 5 TP1 THRU IO ae pe F D SINGLE B 300 4400 2 E Dyes ten 650 0001 0 DEM a NEXT ASSY 5 TABEET CONT _ J
28. MULTIPLEXER DRIVERS SEL O DIRN DIRN DELAY Figure 3 11 Positioner Control Circuit Block Diagram The positioner control circuit consists of an NE555 timer connected as a gated oscillator U12 a dual and or gate U17 which is used as a multi plexer and three flip flops U11 5 U11 9 and U19 5 which comprise the sequencer Figure 3 12 shows the timing relationships for the positioner control circuit operation m 3 16 102001A 102001A CLK 1 52 53 a fa es s SBSY b bin Figure 3 12 Positioner Control Circuit Timing Diagram Initially the oscillator is held clear and the flip flops are reset When a step pulse occurs with the drive selected and not writing a positive going pulse is generated at U18 12 The trailing edge of this pulse sets flip flop 011 5 so that a Hold driver U5 is deenergized b The SBSY line is set high starting the NE555 oscillator and inhibiting writing via U18 10 Sh 6 of Dwg 100072 for the duration of the stepping cycle oscillator then sets 011 9 019 5 in turn The sequencer logic outputs are applied to the multiplexer The polarity of the direction signal DIRN or DIRN conditions the multiplexer to produce the appropriate phase sequence These sequential signals are applied to drivers U4 3 U3 5 U4 5 U5 3 and U5 5 causing the stepper motor to step in DIRN low or step out DIRN high Diodes CR2 CR4
29. SWITCH WRITE LATCH LOAD RECEIVER TAB PROTECT MECHANISM SOLENOID SWITCH Figure 6 8 Head Load Solenoid Write Protect Switch and Latch Mechanism b Connect wires to the replacement solenoid c Lift the head load arm and slide the head load solenoid into position on the chassis d Align the solenoid mounting hole and key with respective holes in the chassis then install the mounting screw and lockwasher Check freedom of solenoid action by manually operating the solenoid plate f If the tie wrap was cut in step a replace it loosely to avoid crushing the head cable 102001A 6 11 6 9 CLAMP ASSEMBLY The clamp assembly consists of the clamp and clamp support plate The clamp assembly is accessible when the PCBA is removed a Remove the two clamp support plate retaining nuts and washers see figure 6 9 DISKETTE EJECTOR CLAMP SUPPORT PLATE Figure 6 9 Clamp and Clamp Support Plate b Disconnect the ejection spring from the clamp support plate then remove the clamp support plate and clamp from the drive mechanism c Install the replacement clamp support plate with clamp and secure with nuts and flat washers d Reattach the ejection spring to the clamp support plate e Perform the Clamp Support Plate test and adjustment paragraph 4 14 6 10 SPINDLE ASSEMBLY The spindle assembly consists of the spindle and spindle housing the large drive pulley and strobe disk and the spindle and lead screw bea
30. Single A Drive Electronics PCBA 100071 XX X see schematic dwg 100072 for versions Single B Drive Electronics PCBA 100163 XX X see schematic dwg 100164 for versions Drive Mechanism MOD I 48TPI 100075 01 9 MOD II 100TPI 100075 02 7 Bezel 100028 01 8 Clamp Assy 100078 01 3 Door Open Switch 612 0001 0 Drive Belt 725 1201 5 Drive Motor Tachometer 100012 01 2 Drive Pulley Large 100007 01 2 Head Carriage Assy Single Side 100034 01 6 48TPI Single Side 100037 01 9 100TPI Head Load Arm 100036 01 1 Head Load Pad 100074 01 2 Head Load Solenoid Assy 2 100079 01 1 Latch Mechanism 709 0001 4 102001A 7 1 TABLE 7 1 OEM FLOPPY DISK DRIVE PARTS LIST cont Description i Figure Ref LED Assy 100023 01 9 Molex Pin 681 0003 1 Mounting Nut 6 Plastic 710 0605 0 Pin Dowel Carriage Assy Lower 717 0602 2 Pin Dowel Carriage Assy Upper 717 0601 4 Pivot 100014 01 8 Platen Assy 100029 01 6 Positioner Assy 48TPI 100076 01 9 100TPI 100076 02 7 Receiver Assy MOD I 100015 01 5 MOD II 100015 02 3 Screw 5 16 Taptite I 703 0605 5 Spindle Assy 100077 01 5 Spring Carriage Assy 715 2002 7 Spring Door Open 715 1002 8 Spring Diskette Eject 715 2001 9 Standoff Maintenance 100100 02 3 Standoff Shipping 709 0002 2 Track Zero Switch Assy 100081 01 7 Write Protect Switch 612 0001 0 7 2 102001A 102001A SECTION VIII ASSEMBLY DRAWINGS AND SCHEMAT
31. TABLET CONT 500 4402 8 CODE IDENT NO DWG NO s se T SHEET Ex p 5V 01 220 5500 TERM PACK 16 i m BE p 4 2 Q HDLD 7438 HDLD lt RDY G of UEP t gt ROY 4 5 WCS lt 3 7 SECP 8 l 116 MTRN MTRN lt SECP 15 71 Q 1514 om ies fan DIRN z LSI4 SBSY 260 E ED DIRN 3 MET UIS 251 4 20 STEP STEP lt 19 L WPT 28 514 ee 2 d Lu WDA gt WPT TOM 21 Jis SEL 27 Q 7416 24 6 WRT ON 5 B WRT 123 RDA LS14 291 132 E E HSLT 5 e I P HSLT lt LSI4 31 L 10 i B HSLT zt UIE 110 DSI 4 9 i2 DS2 SEL 14 DS 3 m 13 GRATION NE OF dis qara du De ea SEL used or duolicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS ps4 MICROPOLIS SIZE ICODE IDENT NO DWG NO z E e LII SHEET 2 or 9 fo g WN e 5V PSEN ti2y J _STEPPER MOTOR m py 20K CCW 8 CR2 vj aM IN5237B l 555 b dg CR3 Se IN4002 4 CI 22 L 1527 STEP 3G SEL
32. Zero Switch and Zero Stop 4 10 6 11 INDEX SECTOR LED ASSEMBLY The Index Sector LED Assembly consists of a light emitting diode LED on a bracket It is accessible when the PCBA is removed a EE the two LED Assembly retaining nuts and washers see figure 6 11 b Turn the LED Assembly on end to gain access to the two terminals Note the wire color coding for each terminal then unsolder the wires and remove the LED Assembly c Solder the wires to the feed through terminals on the replacement LED Assembly ensuring that the color coding is as noted in step b d Route the wires through the notch on the underside of the bracket then install the bracket over the studs and secure with two washers and nuts e Perform the Circumferential Azimuth Alignment paragraph 4 8 6 14 102001A 102001A INDEX SECTOR LED BRACKET INDEX SECTOR LED Figure 6 11 Index Sector LED Assembly Details 6 12 INDEX SECTOR PHOTO TRANSISTOR The Index Sector Photo Transistor is part of the Platen Assembly The Platen Assembly is accessible when the drive is removed a While holding the platen see figure 6 12 in place remove two platen mounting screws b Slide the platen toward the side of the chassis until it is freed from the head carriage and spring plate CAUTION Perform the next step carefully since the photo transistor wires will still be attached c Tilt the platen and slide it out between the receiver and the
33. achats Ds Bad RA CRG Head Eoad SOLe8noTQes esa cue e n RIEN ROUEN EN NA Ad be Va add Clamp oss wa We aret ORT CER XAR EUR Spindle ASSemDTY uu ouch CE e E CS UI AU SESS Index Sector LED Assembly sy Gewese xS aa PR eR e ed Index Sector Photo TVANSTS COM es ivo doce e ace CX RO ACH ES Woite Protect SWITCH is ue Gash ew EXT TE Y e ae See ERA de Door Open SWITLOhlu wies usay x xe va SR ER AEST EI RECO IVE S s ortus um RENE wa Ree hw Rae Sean d S aad e as Track Zero tenuate doce ERE XX 3a X Eau ede vi USE d es das ewe mace aw oS va EN C tases kde OE e RS iv 102001A TABLE OF CONTENTS cont SECTION VII PARTS LIST Abed LAULCOCUCT ION sss VER OP acu P ce D arae 7 1 SECTION VIII ASSEMBLY DRAWINGS AND SCHEMATIC DIAGRAMS Bl Introductiollea gu pt S nucon tan esa X uwa au 8 1 LIST OF FIGURES Figure Title Page 1 1 Micropolis OEM Floppy Disk Drive 1 2 2 1 Drive Mounting Detail lS vic l yy cae nates wire 2 2 3 1 Typical Drive Mechanism ee eee 3 1 3 2 Interface Characteristics as ava we ces Garey eee ewww d Oe tw 3 4 3 3 Major Signal General Timing 3 6 3 4 Positioner Control General Timing Requirements 3 7 3 5 Index Sector General Timing Requirements
34. and the limits of step e are met When the block is correctly adjusted remove the maintenance standoff 4 18 102001 102001A 4 13 WRITE PROTECT SWITCH The write protect switch is mounted on a tab on the receiver on the opposite side from the door open switch It senses the presence of a slot or no slot covered by a write protect tab to inhibit writing on the diskette The write protect switch should be adjusted whenever a The switch is replaced b False detection of either a write protected or a write enabled condition occurs 4 13 1 Procedure a Connect an ohmmeter between the Black and the Write Brown wires in the 12 position Molex connector on the drive mechanism b Normally with no diskette inserted the switch is open no continuity indication c Insert feeler gauges from the front of the drive on the left side of the receiver slot Use feelers ranging from 0 020 inch to 0 050 inch and observe the ohmmeter for a continuity indication Use the following acceptance criteria Continuity indication for gauge thicknesses in range 0 025 to 0 045 inch is acceptable Below 0 025 inch no continuity is required Above 0 045 inch continuity is unacceptable NOTE When adjusting the switch use care not to break the mounting tab on the receiver d To adjust the write protect switch slightly loosen the two screws that hold the switch to the receiver tab Rotate the switch so the first continuity indica
35. at U11 10 The trailing edge of this pulse sets flip flop U13 9 so that a Hold driver U5 is deenergized b The SBSY line is set high starting the NE555 oscillator and inhibiting writing via U20 13 Sh 6 of Dwg 100164 for the duration of the stepping cycle The oscillator then sets U13 5 and U21 5 in turn The sequencer logic outputs are applied to the multiplexer The polarity of the direction signal DIRN or DIRN conditions the multiplexer to produce the appropriate phase sequence These sequential signals are applied to drivers U4 3 U3 3 U4 5 U5 5 and U5 3 causing the stepper motor to step in DIRN low or step out DIRN high 3 28 102001A Diodes CR3 CR4 CR5 and CR6 in conjunction with zener diode CR2 limit the turnoff transient to 20V Referring to Figure 3 19 it can be seen that the step sequence is complete at the end of SBSY approximately 23 ms If after a further 12 ms i e a total of 35 ms after a step pulse a further step command has not been received hold driver U5 3 is deenergized via the delay circuit U9 12 010 8 R6 and C33 A hold current of about half the original value is then supplied via U5 5 and resistors R7 R8 R9 and R10 This scheme allows a system and motor power reduction in the standby mode 3 5 7 Miscellaneous Control Circuits These circuits perform several functions Debounce the drive switch closures Reshape the pulses from the index transducer Control the head load solenoid
36. cable and cable connector very carefully because they are fragile and irreparable b Note the location of the tie wraps securing the head cable to the PCBA then cut the tie wraps c Disconnect the head cable at PCBA connector J6 d Remove two PCBA mounting screws then lift the PCBA off the drive mechanism INDEX LED DRIVE MOTOR PHOTO TRANSISTOR DRIVE SWITCHES STEPPER MOTOR HEAD LOAD SOLENOID 033 4 MOUNTING AN SCREW INTERFACE CONNECTOR 01 Not Used J2 J5 REGULATED DC POWER MOUNTING 6 T R SCREW CONNECTOR J6 Figure 6 2 PCBA Mounting Details 6 2 102001 102001A e Position the replacement PCBA so that it is supported between the fingers on the bezel f Install the two PCBA mounting screws CAUTION During the next two steps handle the head cable very carefully g Mate the head cable connector with J6 on the PCBA CAUTION During the following step loosely instal the tie wraps to prevent crushing the head cable h Install tie wraps around head cable locating them as noted in Step b i Mate the four drive to PCBA connectors with the PCBA orienting them as noted in step a Note that on the Single B PCBA P N 100163 there is one extra pin on P4 mates with J4 nearest the front of the PCBA j Perform the following tests and adjustments in the order listed Procedure Paragraph Drive Motor Speed 4 3 Positioner Step Timing 4 5
37. elements are shown in block diagram form in figure 3 13 The paragraphs POSITIONER CONTROL STEP MOTOR DRIVERS INTERFACE CIRCUITS TRACK SWITCHES TRANSDUCER AND SOLENOID HSLT HEAD SELECT RO READ MTRN MOTO DRIVE ASSEMBLY Figure 3 13 Single B Overall Block Diagram 102001A 3 19 that follow provide a detailed explanation of each functional element The circuit descriptions are supported by block diagrams detailed schematic diagrams are located in Section 8 of this manual The schematics are referenced by drawing and sheet number to facilitate their use 3 5 1 Comparison With Single A PCBA The Single B PCBA is similar to the Single A PCBA that it replaces Three additional features are included on the Single B a Optional circuits to accommodate dual heads for double sided operation b Automatic drive motor turn on for two seconds to seat the diskette c Digital noise filtering The Single B PCBA is compatible with the older Single A PCBA and may be used as a replacement for the Single A The interface interconnection and power requirements are essentially unchanged 3 5 2 Interface Circuits Sh 2 of Dwg 100164 The interface circuits consist of line receivers input terminators line drivers and drive selection logic Input signals are terminated by 220 330 ohm terminator pack U17 As discussed in paragraph 2 7 1 add on drives have the terminat
38. follower The positioner control and lead screw are preloaded against a bearing in the spindle housing by a flexure spring This referencing technique substantially removes the base plate from the thermal expansion and mechanical stability loops The lead screw pitch is chosen so that four ministeps are taken to move one track This reduces by a factor of four the effects of stepper motor inaccuracy and hysteresis effects caused by friction Sequencing of the phases is organized by the control electronics see paragraph 3 4 5 for Single A or 3 5 6 for Single B A track zero switch is mounted on the chassis such that an extension of the head carriage activates the switch between tracks 0 and 1 A mechanical stop prevents the carriage from moving behind the track zero position 102001 CM 3 2 4 Interlocks There are two electrical switch interlocks and a mechanical interlock The door open switch is an interlock that deenergizes the drive motor and causes loss of the Ready status when the door is open The switch is adjusted to close as soon as the receiver assembly is lowered so the motor is rotating before the diskette is actually clamped to the spindle The write protect switch senses the presence or absence of a notch in the diskette jacket for write protection The normal write protect convention specifies that the diskette is write protected if the write enable notch is covered by a write protect tab thereby keeping the switc
39. forward the same amount and tighten both of the mounting screws The block should now be parallel to the slot in which the block sits If it is not readjust as necessary The block must be parallel to the slot before continuing Use a force gauge to measure the force required to pull the positioner so that the C clip just starts to leave the bearing in the spindle housing This force should be between 2 and 3 pounds If the force in step j is too high move the positioner mounting block away from the spindle if the force is too low move the block toward the spindle Repeat steps j and k until the force is correct Repeat steps a through e If misstepping still occurs or the limits of step e are not met it is because the mounting block is not set exactly parallel to the slot proceed to step m for fine adjustment If the block is set correctly proceed to step p NOTE Steps m and n which follow can be interactive so the fine adjustment process can be iterative Ability to apply more pressure at point 1 than point 2 in step e indicates that the 1 side of the mounting block should be moved toward the spindle and vice versa Ability to apply more pressure at point 4 than point 3 indicates that the block as a whole should be moved toward the spindle and vice versa The block should only be moved approximately 1 64 inch at a time Repeat steps d and e and readjust per steps m and n as necessary until misstepping is eliminated
40. milliseconds average Drive motor start time 1 second Head load time 75 milliseconds Access time Track to track 30 milliseconds Settling time 10 milliseconds Transfer rate 250 Kbits second 102001A 1 3 TABLE 1 1 SPECIFICATIONS cont Drive Characteristics cont Recording density 1015 MOD I 5162 bits per inch 1015 MOD II 5248 bits per inch 1016 MOD II 6380 bits per inch Track density MOD I 48 tracks per inch MOD II 100 tracks per inch Total tracks per surface MOD I 35 MOD II 77 Media size 5 inch Reliability Maintainability MTBF 8000 hours MTTR 0 5 hour Media life 3 x 109 passes on single track Head life 10 000 hours Soft error rate 1 in 10 Hard error rate 1 in 1012 Seek error rate 1 in 109 1 4 MAINTENANCE PHILOSOPHY Micropolis Floppy Disk Drives are designed for trouble free operation Most maintenance operations require a high degree of technical sophistication the proper training and the proper equipment Non technical end users should NOT attempt to perform either preventive or corrective maintenance 1 4 1 End User Maintenance The isolation and correction of faults within the disk drive requires sophisticated test equipment and experience in the field of analog and digital troubleshooting Unless you have been trained by Micropolis and have the necessary tools and equipment you should make no attempt to perform tests adjustments or replacements If the checks in
41. not proceed with step g Figure 4 9 Track Zero Switch Test Waveform Slightly loosen the three track zero switch mounting screws see figure 4 6 Use a screwdriver as a wedge through the track zero switch access slot to move the switch bracket backward or forward to line up the transitions referred to in step f above Tighten the track zero switch mounting screws The track zero stop see figure 4 11 should be set so that when the head is positioned at track zero the positioner cannot move the head more than one third of a step behind track zero If necessary loosen the track zero stop set screw and reset the stop so that the drive screw can rotate 5 to 10 past track zero before the carriage hits the stop The 5 to 10 free movement must be provided to prevent the 4 14 102001A 102001A head carriage from hitting the stop due to overshoot when positioning to track zero normally 4 11 DOOR OPEN SWITCH The door open switch see figure 4 10 is set to activate when the receiver assembly has been moved the minimum amount from its full open position The door open switch should be adjusted whenever a The door open switch has been replaced b The receiver assembly has been replaced c There is evidence of diskette misclamping DOOR OPEN SWITCH MOUNTING SCREWS SWITCH DOOR ACTUATOR OPEN SWITCH Figure 4 10 Door Open Switch and Mounting Location 4 15 4 11 1 Procedure NOTE This procedure can be p
42. of driver U13 does not 3 14 102001A follow the change of state until delay network R26 C16 times out approximately 400 usec At this time U13 senses the high state of U20 12 and U13 3 goes low This condition causes the erase current to flow from the center tap of the head through the erase winding and diode CR11 The amount of erase current is determined by the values of R34 and R35 At the conclusion of the write operation U20 12 goes low As in the previous paragraph the output of U13 does not follow this state until another delay circuit consisting of R25 and C16 times out approximately 800 usec At the end of that period U13 3 goes high and the erase current stops flowing Diode CR8 absorbs the inductive emf when the head winding current stops e Read Write Switch The read write switch consists of diodes CR12 through CR17 and resistors R39 R40 R45 and R46 The function of this switch is to isolate the read circuit from the considerabte voltage excursions which occur when a write operation is in effect and to allow the read circuits to access the head when the read mode is selected When the write command occurs and Q3 conducts the anodes of CR14 and CR15 go to about 11 5V Thus all the cathode junctions of diodes CR12 through CR17 are at about 11V Since the anodes of diodes CR16 and CR17 cannot rise above the 6 7V clamp in the read circuits paragraph 3 4 3 CR16 and CR17 are back biased and the read circui
43. or any part thereof altered defaced or removed This warranty is in lieu of all other warranties expressed or implied including those of merchantability or fitness for purpose CHANGE RECORD Date Pages Changed Brief Description Dec 1979 Initial Release ii 102001A TABLE OF CONTENTS Paragraph Title SECTION I GENERAL INFORMATION ON tag cc r dx ass SR IRR BR oe sie ws eee 1 1 L 2 cS60D8 OT Manual aia s Bae w ua VEDO e s 1 1 l3 Description OF D IVeS C wen aie cern Sa wade aS wd Oe Wo eM 1 2 1 4 Maintenance 11 1 4 1 4 1 End User Maintenant l u sss me eR RR ERROR SOS wee eb ea Ss dE ine 1 4 1 4 2 Dealer Service CaOnters cas ate oa dosis Un E s V ONE ates 1 5 1401 3 Micropolis Repair GR ies NOCERE 1 6 1 5 Maintenance Equipment 1 6 Leo Alrgnnent ue am VET EP Ra NEN OT Re ORE REM 1 7 LG Preventive va veau oe odes WeUCCDOEOL E asua hukuy kas E 1 7 Lost Cleaning the Head d RE 1 8 1 6 2 Lead Screw 1 1 1 1 9 1 6 3 Latch Mechanism Lubrication 1 9 Let SOPKECCIVE MaTntenances sis ewe es aa 1 9 1 8 Spare POPUSur yuy a cyte tate ad V E Ma
44. read head is fed to differentiator U28 Input diodes CR28 and CR29 constitute a clamp circuit that prevents transients generated by the write circuit from propagating through to the read circuits The junction of diodes CR28 and CR29 at V2 is held at approximately 6 7V This voltage is generated in voltage divider R41 R42 R43 refer to the discussion of PSEN generation in paragraph 3 5 5a b Differentiator The differentiator consists of U28 and its associated components This element with U26 and U27 functions as a peak detector that generates the signal illustrated in the timing diagram of figure 3 16 which shows the read waveforms for a sequence of 1 s Thus the output of U28 crosses the zero base line each time a peak is detected on the input signal Capacitor C25 yields the required 6 dB per octave rising characteristic of a differen tiator Resistor R56 terminates this characteristic at 250 kHz This stage has an approximate gain of 40 at 125 kHz c Filter The balanced output of U28 at pins 7 and 8 is applied to an LCR filter that provides a phase shift as a function of frequency This is the linear function required for true data reproduction of the read data R57 and R58 and V1 maintain the read signal at the center of U27 s linear range 3 22 102001 102001A d Fa READ SIGNAL INPUT A B 2 MV TYPICAL U 27 8 1 5V PP TYPICAL U 26 7 U 25 5 Figure 3 16 Single B Read Waveforms Amplif
45. read signal appears as spikes on read amplifier waveform 5 3 TABLE 5 1 TROUBLESHOOTING CHART cont Adjust clamp support Clean with alcohol Adjust diskette rear stop Replace clamp Apply heavy coat of lubricant Replace latch mechanism Change diskette Clean head Replace head load pad Check ISV Check or replace drive belt and motor May be internal faulty drive motor etc or external high bus noise level noisy cabling radiating CRT poor electrical ground Isolate source and repair replace TABLE 5 1 TROUBLESHOOTING CHART cont Soft non permanent read errors cont Troubleshoot read circuits including amplifiers one shots and input select diodes or replace PCBA Intermittent or marginal component in read circuit on PCBA Check for read data at interface pin 30 Check for read signal at read test point Check for read signal at output of first read amplifier Failure of read circuit component PCBA Hard permanent read errors Head is dirty or Clean head contaminated with oxide Write errors Head load pad is Replace head load dirty or contaminated pad with oxide Check switch for noisy contacts Troubleshoot write protect circuit Intermittent write I protect switch o
46. step f Lift the door handle to release the diskette ejector Remove the clamp assembly from the original receiver and reinstall it on the replacement receiver see paragraph 6 9 Perform the following tests and adjustments in the order listed Procedure Paragraph Door Open Switch 4 11 Write Protect Switch 4 13 Clamp Support Plate 4 14 Diskette Rear Stop 4 15 6 16 TRACK ZERO SWITCH The track zero switch and its bracket are replaced as n assembly The track zero switch assembly is accessible after the drive is removed and the PCBA is removed from the drive Remove the three mounting screws securing the switch bracket to the chassis see figure 6 15 6 20 1020014 TRACK ZERO SWITCH DISKETTE EJECTION SPRING TRACK ZERO SWITCH BRACKET MOUNTING SCREWS Ds s d ee Figure 6 15 Track Zero Switch Details 102001A 6 21 b Tilt the switch bracket for better access to the switch terminals then note the color coding of the wires at the three switch terminals Unsolder the wires The switch and bracket can now be removed between the lead screw and the diskette ejector c Position the replacement track zero switch assembly approximately in place Observing the color coding noted in step b solder the three wires to the switch d Loosely install the three mounting screws Aa the Track Zero Switch and Zero Stop adjustment paragraph 4 10 6 17 LATCH MECHANISM The latch mechanism is part o
47. table 1 2 do not isolate or correct the fault notify the appropriate service personnel 1 4 102001A TABLE 1 2 END USER TROUBLESHOOTING Symptom Probable Cause Corrective Action Motor does not turn No power to drive and select indicator never lights Select indicator Interface cable not connected to drive or never lights plugged into controller Controller not plugged into computer or computer not turned on Computer power supply voltages are incorrect Drive is always Interface cable is reversed at one end selected Program cannot be Inadequate memory the memory requirements for loaded procedure in the high data transfer rates associated with the the system user s Micropolis drives may exceed the capabilities of manual has been the computer s memory Try substituting memory followed made by a different manufacturer Permanent 1 0 1 Inadequate memory see above errors occur 2 Computer timing problem there have been many changes improvements made to various brands of microcomputers to improve opera tion with disk memory systems Check with Micropolis Product Support and or the computer manufacturer to determine whether these changes have been incorporated in your System Drive fault try using a known good drive Controller fault try substituting a known good controller NOTE This chart is intended only as a first level diagnostic aid for system level troubleshooting Section V contains a more th
48. that reduces the current surge caused by motor startup When the motor on command is received transistor Q7 goes into saturation and collector current would normally rise to a larger value since the motor is still stationary However the current feedback network consisting of Q6 and its associated components will limit this initial surge to a maximum of 0 8 amp Resistor R83 provides a convenient point to monitor the motor current 102001A 3 21 Diode CR34 protects Q7 from inductive kickback caused by commutation L6 C40 C41 C42 and C43 provide filtering to prevent high frequency transients generated by the motor from propagating into the drive electronics through the power supply 3 5 4 Read Circuitry Sh 7 of Dwg 100164 The read circuitry processes the low level information from the read head during the read cycle reshaping it into a digital pulse stream Figure 3 15 is a block diagram of the read circuitry The 12V supplied to the elements in these circuits is filtered through L5 to provide additional noise isolation Voltage divider R54 R55 and filter capacitor C24 develop a reference voltage referred to as V1 of approximately 6V used in the circuits discussed below DIREC DIGITAL R DATA MPARA n FILTER AMPLIFIER T SUR NOISE ONAL FILTER ONE SHOT SYSTEM FROM READ WRITE SWITCH CIRCUIT R59 Figure 3 15 Single B Read Circuitry Block Diagram a Input Clamp The low level signal approx 1 5 mV pp from the
49. the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duolicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS PARTOR NOMENCLATURE 1 REQD IDENT IDENTIFYING NO _ _OR DESCRIPTION PARTS LIST UNLESS OTHERWISE SPECIFIED CONTRACT NO T i DIMENSIONS ARE IN INCHES 2 0 MIROPOLIS _ MICROPOLIS TOLERANCES ON OR BY F D SINGLE A FRAC DECIMALS ANGLES TONS X XX WK lt APPROVED BY E MATERIAL FINISH SIZE CODE IDENT NO DWG NO iD 100072 DO SCALE DRAWING dse SHEET 5 OF 9 REVISIONS ZONE LTR DESCRIPTION Date APPROVED 5V 12V R22 R23 R32 R43 IK 180 Q2 IK 330 t Venaso2 C n PSEN L 100 f GI N 2N4400 CRE 1 8K IN5223B Ww BSY R24 R42 330 680 500 UIO WPTSW us J 2 CRIS SBSY q CRIS A R45 27K WDA 12V F R46 27K B The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duolicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS amm L mamas cie cig REQD IDENT _ IDENTIFYING NO OR DESCRIPTION 047 Ol Ol PARTS LIST MICROPQLIS ww 1 ED SINGLE A MATERA 7 APPROVED BY
50. 072 The head load solenoid is energized whenever the drive is selected or the HDLD signal is true This latter mode allows the head to remain loaded even when the drive is deselected for example to avoid incurring a head load time in overlap operations such as drive to drive disk copying Whenever the SEL or HDLD signal is low the output of U10 11 goes high This energizes the head load solenoid driver U3 3 if the motor is enabled MTRN low PSEN is high and the drive door is closed DOOR is low 3 4 6 4 Drive Ready Signal Sh 4 of Dwg 100072 When the MTRN PSEN and DOOR signals become true a lisecond delay circuit consisting of U7 12 R12 C14 C15 and U8 4 is enabled After the delay the drive ready RDY signal is produced This delay allows the drive motor to reach operational speed before proceeding 3 18 102001A 3 5 SINGLE B DRIVE ELECTRONICS The Single B Drive Electronics PCBA P N 100163 contains the control circuitry for the drive The Single B PCBA controls the operation of the drive mechanism as well as reading and writing of data The PCBA connects to the drive mechanism with a number of molex connectors the interface connection to the host controller is discussed in section 3 3 The Single B PCBA consists of the following functional elements Interface Circuits Motor Control Circuit Read Circuitry Write Circuitry Positioner Control Circuit Miscellaneous Control Circuits D a U wm These
51. 1 Frequency counter 0 to 10 MHz optional Micropolis Flexible Disk Exerciser Model 1099 optional C Special Items Freon TF or isopropyl alcohol Maintenance standoff Micropolis 100100 02 3 Lubricant Saunders Magnalube Micropolis 732 0001 C E Alignment Diskette Dysan 282 see paragraph 1 5 1 901A fo ce 1 6 ie 1 5 1 Alignment Diskette The alignment diskette is a Dysan P N 282 Micropolis P N 641 0590 1 The following tracks of this diskette are used Track 1 MOD I 1 5 op a Index photo transistor alignment Radial cat s eye alignment also reference track Us Nip 2M for absolute track positioning i e correct track 0 switch setting Track 35 MOD I M DE in conjunction with track pes I or track 5 MOD II for setting of azimuth perpendicular head Track 76 MOD II movement CAUTION Care should be exercised not to erase the prerecorded alignment tracks Do not defeat or override the write pro tect feature of the drive or diskette Do not install the alignment diskette in a drive with a suspected write logic or write protect logic failure NEVER unplug the drive s head connector with any diskette installed 1 6 PREVENTIVE MAINTENANCE Micropolis Floppy Disk Drives do not io preventive maintenance when used in the following environment Dustfree 65 to 80 ambient C Eight hours of operation per day or less with power applied motor running and a head load cycle of 25 or less
52. 37 R36 R38 refer to the discussion of PSEN generation in paragraph 3 4 4a b Differentiator The differentiator consists of U24 and its associated components This element with U22 and U23 functions as a peak detector that generates the signal illustrated in the timing diagram of figure 3 9 which shows the read waveforms for a sequence of 1 s Thus the output of U24 crosses the zero base line each time a peak is detected on the input signal Capacitor C25 yields the required 6 dB per octave rising characteristic of a differen tiator Resistor R51 terminates this characteristic at 250 kHz This stage has an approximate gain of 40 at 125 kHz c Filter The balanced output of U24 at pins 7 and 8 is applied to an LCR filter that provides a phase shift as a function of frequency This is the linear function required for true data reproduction of the read data R52 and R53 and V1 maintain the read signal at the center of U23 s linear range 102001A 3 11 f READ SIGNAL INPUT A B U24 8 022 7 021 13 021 5 Figure 3 9 Single A Read Waveforms Amplifier The amplifier consists of U23 and resistors R54 and R55 The gain of this stage is approximately 50 and can be adjusted by R54 The balanced output of this amplifier is AC coupled into a comparator by capacitors C31 and C32 and resistors R58 and R59 Resistors R56 and R57 center the output signal from U23 at the V1 reference potential Comparator Th
53. 38 0 406 0451 4 406 0452 2 u4 U3 U5 U22 02 015 023 024 Ue 410 0511 2 410 0555 4 410 0592 7 410 0741 0 622 0001 9 CR27 650 0001 0 HEATSINK 680 1601 3 33 74 680 1001 6 J5 T6 SOCKET UI5 SOCKET WI 2 3 4 2 5 4 5 6 684 0004 5 680 1603 9 680 0802 8 684 0003 5 REVISIONS REVISIONS NE LTR DESCRIPTION DATE APPROVED DESCRIPTION DATE APPROVED ZONEIL zz ed ja O SEIm enn e REVISED EN 0079 mm REVISED ENO09I lol enone az TABLE II VERSION R3 CHARACTERISTIC TERM PACK O R3 2 37K 19 HEADER 5 PIN I C TES 15 0001 4 105 2371 9 680 0505 2 2 37K 1 HEADER 5 PIN ae 105 2 371 9 EE 220 330 0 21K 19 220 oW 4 7K HEADER 5PIN Ace 15 0001 4 105 1211 9 101 2200 0 680 0505 2 21K 1 220n Vew 4 7 K HEADER 5 PIN NO TERM 48 TPI 105 1211 9 101 2200 0 100 4700 7 680 0503 2 TABLE III LAST USED DELETED a FOR LAST USED AND DELETED REF DESIGNATION SEE TABLE TIT FOR COMPONENTS AFFECTED BY VERSION SEE TABLE II FOR PART OF COMPONENTS NOT AFFECTED BY VERSION SEE TABLE I FOR PCBA SEE DRAWING NO 100071 ALL DIODES ARE IN 4446 ALL CAPACITOR VALUES ARE IN MICROFARADS I ALL RESISTOR VALUES ARE IN OHMS Aw t 5 o 2 NOTE UNLESS OTHERWISE SPECIFIED F D
54. 446 HEADER HEADER oe DUAL HEAD 410 0555 41500 4402 8 200 4446 71680 0506 5680 0505 7 HEADER 2 80K 7 o sson Vow REVISIONS jzoN TR o o DATE APPROVED ZONE LTR e ae E ee a Edo oe 22 m4 RELEASE enous sizare eo pe Enote tee HL EN 0206 EE ENOlI22 R41 R42 VALUES CP SA TABLE t h GAS iM EN 0390 _ BEDE R30 R3I R35 R36 R38 R39 R56 R R85 cil R40 R32 Te a fx E NM ERI HEADER 55 7 0470 OLUF 680 0401 9 245 oo 182K 1 120 29 Yow 120 n V w 1 82 1 120 Yow HEADER HEADER PART NO REF DESIGNATION 116 0002 0 PART NO REF DESIGNATION LAST USED NOT USED DELETED 340 0110 7 Q7 115 0001 4 160 3300 3 160 1000 1 160 1500 O 160 4700 3 160 7500 4 UI C35 C4 14 39 C37 c9 C 38 36 400 0000 2 Ui2 I8 400 0002 8 un 400 0014 3 010 16 400 0027 5 U20 400 0051 5 019 400 0074 7 U13 21 23 400 0086 1 U24 400 0123 2 025 401 0016 6 02 9 A TABLE 401 001 4 u22 401 0038 0 UI CI7 18 19 20 23 161 1501 6 161 4701 9 161 2202 0 c28 c25 C32 33 162 4702 5 162 1004 9 163 2203 4 163 4703 I 163 3304 9 CIO c57 CI C29 30 47 48 C24 26 40 42 44 49 51 406 0451 4 04 14 406 0452 2 U3 5 7 FOR
55. 5 5 Ol TPI an conr WIO Q O J2 HE PN b g2 o The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed 4 used or duplicated for procurement or manufacturing purposes Q without specific written consent of MICROPOLIS iL 07 MICROPOLIS SIZE CODE IDENT DWG NO sug s5 Erg
56. 9 CR20 and CR22 through CR27 and resistors R44 R45 R48 and R49 The function of this switch is to isolate the read circuit from the considerable voltage excursions which occur when a write operation is in effect and to allow the read circuits to access the head when the read mode is selected When the write command occurs and Q3 conducts the anodes of CR24 and CR25 go to about 11 5V Thus all the cathode junctions of diodes CR22 through CR27 are at about 11V Since the anodes of diodes CR26 and 3 26 102001A 102001A CR27 cannot rise above the 6 7V clamp in the read circuits paragraph 3 5 4 CR26 and CR27 are back biased and the read circuits are effectively isolated from the read write head When the read mode is selected Q3 is cut off since the WRT signal is high at U20 1 Under these conditions the circuit stabilizes with CR24 and CR25 cut off and diodes CR22 CR23 CR26 and CR27 conducting The anodes of CR22 and CR23 are at approximately 6V as established by the voltage dividers consisting of R41 R42 and R43 and Q4 and R37 or Q5 and R40 Approximately 0 25 ma is supplied through resistors R48 and R49 and diodes CR26 and CR27 About 0 5 ma is drawn through R44 and R45 Thus each of the four diodes have approximately 0 25 ma of current flowing through them In this way the diode bridge provides a low impedance path for the head signal to differentiator U28 Sh 7 of Dwg 100164 3 5 6 Positioner Control Circuit Sh
57. E Instantaneous Speed 1 1 1 FOS TEIONGr Step TIMIN RE REGES Ea Ed ed Read ess CRI UU SUC C QU Ds Readr COMP TANCE cope vicis exi ea n eee POOR DU di Circumferential Azimuth Alignment Al Tghnel ss siqua aree Row oa es Track Zero Switch and Zero St0 bes i035 os e EA e a RA Door Open SWLLclus us RSS Ro adt cree a RE waa aoa Rue nd RENS Positioner Mechanical Werte Protect eden a are wie Sas ara ee esia it s Clamp Supports Pate tees Gaels Gud Shea STRE iu Diskette Rear shee sh ese aes SECTION V TROUBLESHOOTING 5 OY 1 I YO ba dox eS CO Ae o mei aD Race Rose a n SE Rar Was S SECTION VI REMOVAL AND REPLACEMENT PROCEDURES Introdgct lol yh a ae Cee ewe eR I Rad ee Disk Drive 1 Drive Etectronics po x exa us Drive Motor or Drive 555 Head Load Eure ua aqe ee E POSTETODBP ese s u Yu EW eT eee es Head Cari saa aa E
58. IC DIAGRAMS 8 1 INTRODUCTION This section consists of engineering documentation for the Single A and Single B Drive Electronics PCBAs Documentation provided is in order Single A PCBA Assembly Drawing 100071 Single A PCBA Schematic 100072 Single B PCBA Assembly Drawing 100163 Single B PCBA Schematic 100164 a 0 oc mw 8 1 T REMSONS DESCRIPTION DATE APPROVED B REVISED AND REDRAWN SSN A A IRE E EN 0I98 12 26 79 o7 44 02 HTSNK OQO APPLY SILICON GREASE BETWEEN XSISTOR amp HTSNK N m FLUSH TO WITHIN 020 160 bh SOCKET 04 030 MAX PIN 2 KEYED 5 PLACES J2 J6 4 48t 05 o2 f 4 15 t 02 03 SOCKET 09 ORIENTATE AS SHOWN Sede 9 zegon tron s ne pepy ot sees used or duplicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS QTY CODE PART OR NOMENCLATURE ZONE REQD IDENT IDENTIFYING NO OR DESCRIPTION PARTS LIST CONTRACT NO MENOS ARE IN INCHES DECIMALS ANGLES PR BY J fazio 5 1577 5 15 77 APPROVED BY ee See 7 22 47 ems PS SIZE CODE IDENT NO DWG NO REV D E APPLICATION DO NOT SCALE DRAWING N SCALE 2 1 suEET TABLE I PART NQ REF DESIGNATION 100 0000 8 IOO IOOO 7 100 I500 6 00 1800 0 100 2200 2 100 3300 9 100 4700 3 IOO 5600 0 100 6800 5 100 1001 5
59. L Figure 3 17 Single B Write Circuitry Block Diagram 3 24 102001A 1020014 a Power Supply Enable Circuit The power supply enable PSEN circuit allows the write current to flow only when the power supply voltages 5V and 12V are within operational tolerances This prevents writing on the diskette during power up or power down sequences of the disk drive or during accidental power loss The PSEN circuit consists of transistors Q1 and Q2 and associated components Initially as 5V power rises to operational level transistor 01 conducts as soon as the base voltage exceeds the zener voltage of CR8 plus the emitter base drop of 01 or about 3 4V When the collector current of Q1 is sufficient to drop 0 7V across R19 transistor Q2 conducts providing 12V to the remaining circuits if the 12V power is present At the same time voltage divider R50 R51 generates a high status signal PSEN The 12V is also divided by R41 R42 and R43 This divider produces about 6 7V which is used in the input clamp of the read circuits see paragraph 3 5 4a The divider also develops approximately 6V This voltage is applied to the center tap of the selected R W head via Q4 or Q5 providing the correct bias for U28 in the read mode Head Select Circuit The Single B PCBA is used in both single and double head drive mechanisms Enclosed within the dotted line on sheet 6 are the write current supply 05 upper R W E erase head
60. LIS QTY cope PART OR NOMENCLATURE SENE REQo IDENT IDENTIFYING NO _ OR DESCRIPTION EGET ALS NEXT ASSY USED ON APPLICATION UNLESS OTHERWISE SPECIFIED CONTRACT NO gt DIMENSIONS ARE IN INCHES TOLERANCES ON DO NOT SCALE DRAWING _ PARTS LIST a MICROPOLIS E FRAC CORE ANGLES Ch ae SINGLE A eae SIZE CODE IDENT NO DWG NO zug ster 209 REVISIONS zone DESCRIPTION DATE APPROVED RIO vee STEPPER MOTOR 20K 8 CCW i1 m rcd cuc CEU c AM NE555 RII 3 o U8 8 6 8K U12 5 T4 SBSY 22 6 1500 4 a CRI IN5237B IN4002 ACR2 IN4002 BCR3 PSEN DIRN DIRN IN4OO2 amp CRS BLACK 2 GREEN jJ pex LIST PARTS OLERANGES ON j MICROPOLIS FRAC DECIMALS ANGLES MATERIAL E D Sl NGLE A ORATION No portion of this data shai be released disclosed XH NORMEN OO 072 used for rem r manufacturi i Sec p eer Om a APPLICATION DO NOT SCALE DRAWING sae sem 3 or 9 The information hereon is the property of MICROPOLIS CORP REVISIONS 12V jj 500 44 HDLD El OR i2 SEL
61. MICROPOLIS MODEL 1015 1016 OEM FLOPPY DISK DRIVES MAINTENANCE MANUAL 15 MICROPOLIS MODEL 1015 1016 OEM FLOPPY DISK DRIVES MAINTENANCE MANUAL PROPRIETARY NOTICE Information contained in this manual may not be duplicated in full or in part without prior written consent of Micropolis Corporation The sole purpose of this manual is to provide service personnel with adequately detailed documentation to efficiently install interface and maintain the Micropolis equipment described The use of this document for all other purposes is prohibited DOCUMENT NO DECEMBER 1979 102001A MICROPOLIS CORPORATION 7959 DEERING AVENUE CANOGA PARK CALIFORNIA 91304 LIMITED WARRANTY Micropolis warrants hardware products of its manufacture to be free from defects in design workmanship and material under normal and proper use and service for a period of three 3 months following delivery to the original Purchaser Micropolis agrees to repair or replace at the place of manufacture without charge all parts of said products which are returned for inspection to its factory within the warranty period provided such inspection discloses that the defects are as above specified and provided also that the equipment has not been altered or repaired other than with Micropolis authorization and by its approved procedures subjected to misuse improper maintenance negligence or accident damaged or had its serial number
62. NO DIMENSIONS ARE IN INCHES TOLERANCES ON FRAC DECIMALS ANGLES ae cee uo APPROVED BY Epes SINGLE A TIONS X Xx dz FINISH Xm SIZE CODE IDENT NO DWG NO NEXT ASSY USED ON 100072 APPLICATION DO NOT SCALE DRAWING a SCALE 2 SHET 9 OF o REVISIONS 7 a APPLY SILICON GREASE c EN 0198 2 r2 74 HTSNK 24 S E H EN 0390 toli 2t Ie t ES BETWEEN XSISTOR HTS EN 451 FLUSH TO WITHIN 020 n jo n a h jo n SOCKET 19 2 SH osos T eg REMOVE PIN 2 BY TWISTING P OFF RIGHT ANGLE SIDE Ale i 8 u MAX o i PIN 2 KEYED ne 4 PLACES PIN I 4 PIN HEADER MUT 100163 58 3 n T IN MIN I00163 56 7 ASSY VERSIONS I00163 58 3 100163 51 8 29 SOCKET 22 ORIENTATE AS SHOWN SEE P L 00163 59 1 100165 53 4 eeo ees ee 1 P The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shali be released disclosed SOT UNLESS OTHERWISE SPECIFIED CONTRACT NO or DIMENSIONS ARE AN INCHES aii MICROPOLIS without specific written consent of MICROPOLIS TOLERANCES ON poR BY N sed or duolicated for procurement manufacturing purpose oxm 1 N PCBA FD SINGLE B MATERI FINISH SIZE CODE IDENT NO DWG NO REV romped j
63. Track Zero Drive Write Protect Drive Read Data Drive Head Select Controller Drive Select 4 Controller Note Jl Mating Connector is Scotchflex P N 3463 001 or equivalent 102001A 3 5 DC Power s Motor On Drive Selected I l 0 5 us max RDY x 0 5 us max Valid m E d Lo 5 LLL WPT Valid SECP Output HDLD DIRN gt lt 250 ns min STEP gt l 30 ms min ur 40 ms q 75 ms min 850 us ap WDA 1 sec min l s us max Valid RDA 1 sec max Figure 3 3 Major Signal General Timing Requirements A ZZ 40 ms max 75 ms max 102001A STEP IN STEP OUT DIRN 250 ns min l 250 ns min INHIBIT READ 40 ms min AND WRITE 30 ms min Figure 3 4 Positioner Control General Timing Requirements 13 14 15 0 1 2 SECP S S S s s s _ _ 3 ms t1ms 12 5 ms 6 25 ms 0 65ms 0 325 ms Figure 3 5 Index Sector General Timing Requirements 102001 3 7 3 4 SINGLE A DRIVE ELECTRONICS The Single A Drive Electronics PCBA P N 100071 contains the control circuitry for the drive Single A PCBA controls the operation of the drive mechanism as well as reading and writing of data The PCBA connects to the drive mechanism with a number of molex connectors the interface connection to the host controller is discussed in
64. ase so that one cycle of the waveform Fills the calibrated part of the screen f ISV will appear as the width of the trace as shown in figure 4 3 The maximum allowable amount of ISV is eight percent of the overall width of one cycle of the waveform If the ISV is greater than 8 troubleshoot to the defective component there is no adjustment Figure 4 3 ISV Test Waveform 4 5 POSITIONER STEP TIMING The phase to phase internal timing for the 4 phase stepper motor positioner is determined by the period for which the gated oscillator U12 for Single A PCBA U6 for Single B PCBA is enabled SBSY high This adjustment should be checked whenever a The PCBA is replaced b Components in the positioner timing circuits are replaced c There is any indication of incorrect positioning 4 5 1 Procedure Apply power to the drive Apply a low signal to the MTRN interface line Jl 16 Insert a work diskette in the drive and load it Apply interface signals that cause the drive to be selected and perform a continuous full track seek 4 4 102001 Connect the oscilloscope to Single A U12 4 and 1 GND Single B TP8 and 1 GND Set the vertical scale to 2V cm and the time base to 5 ms cm Trigger internally positive The positioner step timing will be as shown in figure 4 4 The positive portion of the waveform should be within the following limits 100TPI MOD II 23 5 ms max 21 5 ms
65. ata input WDA The low state of U18 11 also enables the erase current generator through 024 11 014 3 and 014 5 Note that when U21 pins 10 and 13 were both held low pins 8 and 9 of U21 were both in a high state Write Current Driver When the write control logic removes the set and clear direct inputs to write flip flop U21 write data WDA pulses from the interface can be processed by the write current driver circuit When both set and clear were low both outputs were in a high state The flip flop is connected in such a manner that each time a write pulse occurs the flip flop toggles on the trailing edge of that pulse The two complementary outputs of U21 are coupled by power drivers into the read write head through resistors R31 and R32 As the flip flop toggles power drivers U22 2 and 022 12 are energized sequentially thus alternately driving a current through the two halves of the read write head Diodes CR14 and CR15 are used to isolate the write circuits from the head during the read operation to increase noise immunity Resistors R27 and R28 ensure that CR14 and CR15 are back biased when the write operation is concluded Erase Current Driver Resistors R21 and R22 diode CR9 capacitor C10 and timer U15 combine the functions of an erase current driver with a delay generator that generates two different delays from the leading edge and the trailing edge of the input waveform This causes the erase current to be switched on app
66. b WE 1500PF M S 150 PF U23 a 8 CR29 4 i4 iS LS86 13 Tia x 4 5125 0 45 s j AM Rs 330 I 4 C 36 5v 4700 6 2K 220 PF 9 TPS TPIO R69 RDATA 12V F The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duplicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS SIZE ICODE IDENT DWG NO IOOI64 sg TOFS 12 MOTOR TACH L6 IO UH C40 C4lI C42 C43 3 3 Ol 3 3 0 TP7 14 CR3O O R70 C44 I50K 3 5 lis o E m O CR3I IN5235B 6 8V MOT IN4002 00 R83 Vow CR34 C46 ia 13 O DRIVE MOTOR 16 L The information hereon is the property of MICROPOLIS CORP ORATION No portion of this data shall be released disclosed used or duolicated for procurement or manufacturing purposes without specific written consent of MICROPOLIS D P 10064 SCALE NO DWG NO IO 0164 OF 16V UNREG GNO J2A SEND 416v UNREG O 2 x E ox 16V GND x 8V UNREG of 5V 4 8V GND C5 C52 THRU C56
67. ccessible when the PCBA is removed from the drive a Position the head carriage assembly to the middle of its stroke b Pivot the head load arm up until it is vertical and hold it in this position using care to keep the spring and pins in place see figure 6 5 HEAD LOAD PAD HEAD LOAD ARM Raised Figure 6 5 Head Load Arm and Pad c Using tweezers carefully remove the old head load pad from the arm Adhesive will usually remain stuck in the recess in the head load arm Using caution to avoid damaging the head load arm remove all bits of residual adhesive 6 6 102001A 102001 d Being careful not to touch the adhesive surface pee the protective strip from the back of the replacement head load pad CAUTION During the following step make sure that the head load pad is flat An off center and or off level pad will cause data errors e Position the head load pad in the head load arm recess then use a flat tool to press it into place f Lower the head load arm to the head load solenoid plate g Perform the Read Amplifier Gain test and adjustment paragraph 4 6 and the Head Compliance test paragraph 4 7 6 6 POSITIONER The positioner consisting of the stepper motor and lead screw is replaced as a unit The positioner should not be removed until the PCBA is removed Since the head carriage is removed along with the positioner CAUTION During the next step handle the head cable very carefully a
68. ch terminals then unsolder the wires and remove the switch Observing the color coding noted in step b solder the three wires to the replacement switch d Hold the switch in place and insert two mounting screws through the receiver tab and through the switch Hold the nut plate against the screws and loosely run the screws into the nut plate The switch actuator should be positioned down and toward the rear of the drive e Perform the Door Open Switch adjustment paragraph 4 11 6 18 102001A 102001A 6 15 RECEIVER The Receiver Assembly includes the receiver write protect switch door open switch index sector LED and diskette ejector mechanism it does not include the clamp assembly The Receiver Assembly is accessible when the drive is removed and the PCBA is removed from the drive a b LEFT PIVOT POST Loosen the two bezel mounting screws see figure 6 3 Slide the diskette ejector rearward until it latches Move the bezel forward and upward until it clears the door handle then remove the bezel Loosen the left hand pivot post mounting screw then separate the receiver from the left hand pivot see figure 6 14 RECEIVER Figure 6 14 Receiver Details Rotate the receiver on the right hand pivot post while moving the receiver to the left until the receiver is free of the right hand pivot Retain door open spring Note the location of the tie wraps securing the receiver wires t
69. chassis d Note the wire color coding for the two terminals on the platen then unsolder the two wires and remove the platen INDEX SECTOR PHOTO TRANSISTOR PLATEN B BEE RE oak PLATEN ASSEMBLY MOUNT ING poris SCREWS Figure 6 12 Platen Details 6 16 102001A e Solder the wires to the terminals on the replacement platen ensuring that the color coding is as noted in step d Ensure that the blue wire is at the terminal that will be nearer the spindle housing f Lubricate both sides of the platen lip with Magnalube grease Micropolis P N 732 0001 g Tilt the platen and slide it into approximate position on the chassis h Position the platen so that the photo transistor is toward the front of the drive mechanism the spring plate on the head carriage assembly is below the platen lip and the head carriage is above it and the platen mounting holes are aligned over the holes in the chassis i Verify that the head cable is not underneath the platen then install the platen mounting screws j Perform the Circumferential Azimuth Alignment paragraph 4 8 6 13 WRITE PROTECT SWITCH The write protect switch is attached to a tab on the drive motor side of the receiver It is accessible when the drive is removed CAUTION When performing this procedure do not apply stress to the fragile tab to which the switch is mounted If the tab is damaged the entire receiver must be replaced paragraph 6 15 a W
70. crew and attach the spring plate to the head carriage If using a replacement head carriage use the attaching hardware that comes with it Check that the spring plate is perpendicular to the head carriage and to the lead screw and adjust if necessary i Place the positioner with head carriage on the chassis near its installed position but without inserting the lead screw in the spindle housing bearing CAUTION During the next step handle the head cable very carefully j Route the head cable as noted in step a Install tie wraps over cable sleeving but leave them loose to avoid crushing the cable Make sure a service loop is left at the head end 102001A 6 9 k Rotate the lead screw until the head carriage is just inside the retaining ring at the far end the spindle housing end of the lead screw CAUTION During the following step force is NOT needed If the lead screw does not slip into position easily it is not cor rectly aligned with the spindle housing bearing Using force will damage the drive mechanism 1 Make sure the projection on the head load arm will be above the solenoid actuator arm then gently insert the lead screw into the spindle housing bearing m Loosely install the two positioner mounting screws through the spacer plate and positioner mounting block n Adjust the positioner to obtain as accurate a side to side centering as possible then tighten the mounting screws to 18 inch lbs o App
71. cuitry consists of a power supply enable circuit write control logic write current drivers an erase current driver and the read write switch Figure 3 10 is a block diagram of the write circuitry POWER SUPPLY ENABLE PSEN PSEN VOLTAGE DIVIDER WBSY VOLTAGE DIVIDER WRITE POWER CONTROL A READ WRITE SWITCH WRITE CURRENT ORIVER TO READ CIRCUITS 8 ERASE CURRENT DRIVER Figure 3 10 Single A Write Circuitry Block Diagram a Power Supply Enable Circuit The power supply enable PSEN circuit allows the write current to flow only when the power supply voltages 5V and 12V are within operational tolerances This prevents writing on the diskette during power up or power down sequences of the disk drive or during accidental power loss The PSEN circuit consists of transistors Q1 and Q2 and associated components Initially as 5V power rises to operational level transistor 01 conducts as soon as the base voltage exceeds the zener voltage of CR6 plus the emitter base drop of Q1 or about 3 4V When the collector current of Q1 is sufficient to drop 0 7V across R23 transistor Q2 conducts providing 12V to the remaining circuits if the 12V power is present At the same time voltage divider b R43 R44 generates a high status signal PSEN The 12V is also divided by R36 R37 and R38 This divider produces about 6 7V which is used in the input clamp of the rea
72. d circuits see paragraph 3 4 3a Divider R38 R36 also develops approximately 6V This voltage is applied to the center tap of the R W head providing the correct bias for U24 in the read mode Write Control Logic The write control logic provides the necessary Signals to gate and control the write circuits The write control logic consists of elements U18 U10 U20 and U9 This logic controls the operation of the write current driver the erase current driver and the write busy WBSY generator The write control signal for these circuits is generated by four external logic signals gated by U18 and U10 When WRT is low TRUE write protect WPTSW is low FALSE and stepper busy SBSY is low FALSE U18 8 is high enabling gate U10 8 If the drive is selected SEL is high and U10 8 goes low This condition is coupled to the base of 03 via U20 2 generating the write busy WBSY signal As U10 8 goes low inverter U9 10 releases the set and clear direct inputs at pins 10 and 13 of U19 This condition enables U19 to respond to the state of the write data input WDA The low state of 10 8 also enables the erase current generator through U9 10 and U20 12 Note that when U19 pins 10 and 13 were both held low pins 8 and 9 of U19 were both in a high state Write Current Driver When the write control logic removes the set and clear direct inputs to write flip flop U19 write data WDA pulses from the interface be proces
73. d directly in the inner carton 2 5 VISUAL INSPECTION When the drive is unpacked inspect it for any damage If shipping damage of any kind is evident notify the carrier at once NOTE Do not return the damaged drive until the shipping company inspector has reviewed the damage since an insurance claim will be made 2 2 102001A 102001A 2 6 INSTALLING THE DRIVE 2 6 1 General Guidelines The following general guidelines should be adhered to when planning the installation a b The ambient temperature must be in the range of 50 105 F 10 41 C Do not install a drive close to sources of strong electromagnetic or fields i e large transformers CRTs motors etc Avoid dirty dusty or smoky areas Avoid static discharging to any part of the system use anti static spray on carpets Ensure that adequate regulated DC power specified in section 2 8 is available For drives with the optional protective sleeve ensure that the cooling slots are not obstructed 2 6 2 Specific Mounting Requirements Refer to Figure 2 1 and ensure that the following mounting requirements are met The drive may be mounted in any orientation except upside down If the drive is to be mounted with the bezel up it should be ordered as such so the disk eject system can be suitably adjusted Use the recommended panel opening given in figure 2 1 and insert the drive through the panel opening from the front O
74. dboard insert in the carton g Remove the three screws and spacers that hold the drive to the fiberboard base SAVE the base the screws and the spacers In addition save both cartons and the six inch and ten inch foam strips I 102001A 2 1 2 3 RE PACKING THE DRIVE FOR SHIPMENT If it is necessary to re pack the drive for shipment the following procedure must be used g CAUTION Do not attempt to ship the drive except in the original packing Attach the drive to the fiberboard shipping base using three screws and spacers The drive suspended from the base fits in the smaller inner carton the base rests on the cardboard insert Close the flaps and seal with tape If the ten inch wide foam strip has been removed from the larger shipping carton form it into a U shaped cradle in the carton Place the inner carton with the drive in the foam cradle with equal space on either end Form the six inch wide foam strip into a wide inverted U and place it over the inner carton with the legs of the U inside the shipping carton on either end of the inner carton Close the flaps and seal securely with tape 2 4 UNPACKING RE PACKING DRIVES WITH SLEEVES Drives shipped with the optional protective sleeve are not attached to a fiberboard shipping base and the inner carton does not have a cardboard insert The drive is enclosed in a large plastic bag wrapped in Kimpack shipping insulation and place
75. e eb qe ERR 3 3 Sut Index re IRURE VES XS ER E a ds sa 3 3 397 JIntebrtg6eoi RE I OR xa Rh X VOR ENT dU RUE CREE AEN 3 3 3 4 ST gie A Drive ETectroni6eS uas ea bo cas EA n WR UR URS 3 8 ds 4 L Interface CIF CUTS dos sheep yu vd sr ua EE WE AS HR CR Ra HR a 3 9 3 4 2 Motor Control beso per dA ax bx e D IO ER et 3 9 3 0 5 Read CIPCi lt yi ves aug x era e Race aor hi IRR Rew hie ICA 3 11 Weite CIV CULLEN ste su exi uu eae SPA SEA ECKE LEE REX Ed aa 3 13 3 0 5 Positioner Control GIPFGUTU OY dra RADO 3 16 3 4 6 Miscellaneous Control Circuits 3 18 102001A iii TABLE OF CONTENTS cont 5 1 Comparison With Single A Interface tls i e UPON RE eae eae es EV Read Cir CU CRY ina nests e d UC Sa wee he en ween sv ele ees Weite En Cn Ra sebo ern SURE qa iiie Positioner Control CTPCU01U2 2 dua ERR Miscellaneous Control 1 11 WWW CO CO CO CO C1 NOY Co SECTION IV TESTS AND ADJUSTMENTS 01 gt CO PO p 10 11 12 13 14 15 Introducb Oeo S kot ss dace e X do ES e RI pU Adjustient SEN MOSODNY 6633 eu alt Q c ode Ite ac ta ee EO Ce die ee DRIVE Motor Speedi REPE ee Oboe XM
76. e last drive only Figure 3 2 shows the typical receiver driver character istics for the interface Either flat cable or twisted pairs may be used with a maximum total cable length of 20 feet CONTROLLER petes 20 FEET UR MEE ES DRIVE J 7416 OR EQUIV HIGH 105 OHM FLAT CABLE 220 7438 OR TWISTED PAIR Neon 7404 7416 OR EQUIV OR EQUIV HIGH HIGH O i By LOW TRUE 7404 7438 SEGUI 220 OHM OUTPUT HIGH O pH n i NOTES Input Lines TRUE Logic Zero 0 to 0 4V 25 ma max FALSE Logic One 2 5 to 5 25V ma open Output Lines TRUE Logic Zero 0 to 0 4V 48 ma max FALSE Logic One 2 5 to 5 25V 250 ua max open collector INPUT LINES ARE TERMINATED IN LAST DRIVE ONLY I USER MAY USE 150 OHM TO 5V TERMINATION ON OUTPUT LINES IF DESIRED Figure 3 2 Interface Characteristics 3 4 102001A A X Table 3 1 lists the interface signals Detailed information about each signal is given in the Single A and Single B PCBA descriptions Figures 3 3 3 4 and 3 5 show the general timing requirements TABLE 3 1 INTERFACE SIGNALS J1 Connector Pin oe Pin Signal Description Source Head Load Controller Spare Ready Drive Sector Index Pulse Drive Drive Select 1 Controller Drive Select 2 Controller Drive Select 3 Controller Drive Motor On Controller Step Direction Controller Step Command Controller Write Data Controller Write Gate Controller
77. e next stage through resistor R74 3 20 1020014 DC MOTOR R72 SPEED ADJUST AC TACHOMETER CURRENT LIMIT Figure 3 14 Single B Motor Control Circuit Block Diagram b Comparator and Reference Circuit Operational amplifier U7 compares the output of the previous stage with a reference level established by potentiometer R72 and its associated components The reference voltage is developed by a voltage divider network consisting of resistor R71 and zener diode CR31 Potentiometer R72 is connected across the constant voltage source CR31 and in series with temperature compensating diode CR32 and resistor R73 The effect of this network is to produce a temperature compensated adjustable reference level at input U7 3 Resistors R76 and R78 form the feedback loop with a DC gain of 36 The output of U7 feeds the power amplifier drivers through DC coupling netowrk R79 R80 c Power Amplifier Circuits The power amplifier circuits consist of Darlington pair transistor Q7 current limiter circuit Q6 and associated components The operation of power amplifier driver Q7 is controlled by the state of the MOT signal This signal is coupled into the base of Q7 by diode CR33 When MOT is low CR33 conducts and the base of Q7 goes to 0 8V cutting off Q7 When MOT goes high CR33 is cut off allowing the base of Q7 to attain its operational value approx 1 4V Resistors R83 R81 and R82 and transistor Q6 form a feedback circuit
78. e output of the amplifier is processed by low pass filter network R58 R59 C48 thus providing additional noise rejection for this stage Comparator U22 converts the essentially sinusoidal wave shape input into a square wave Figure 3 9 shows this waveform conversion and timing Capacitor C34 and resistor R61 provide a delay for the output of U22 This compensates for the inherently longer turn on delay of U22 thus providing a symmetrical square wave to the next stage Bidirectional One Shot System The output of the comparator at pin 7 is connected to the inputs of dual one shot U21 These one shots are connected so that they each produce a pulse of fixed width correspond ing to the positive and the negative edges respectively of the input waveform Resistor R62 and capacitor C35 control the pulse width of one shot U21 13 while resistor R63 and capacitor C36 perform that function for U21 5 These two signals are ORed together in the interface circuits described in paragraph 3 4 1 bidirectional one shot is reset by U16 3 If the drive is not selected SEL is high causing U16 3 to go low resetting U21 Similarly if the drive 3 12 102001A 102001A is in the write mode WBSY is also high causing U21 to reset This logic prevents noise signals from being transmitted to the interface circuits whenever the drive is in the write mode or the drive is not selected 3 4 4 Write Circuitry Sh 6 of Dwg 100072 The write cir
79. e selected and that can cause the positioner to step inwards and then return to track zero If misstepping occurs proceed directly to the note before step f 4 16 102001A CLAMP CLAMP SUPPORT PLATE TRACK ZERO STOP POSITIONER ROI MENT MOUNTING BLOCK SCREM 1 of 2 LOCKBAR SCREW DISKETTE REAR STOP Figure 4 11 Drive Mechanism Top Rear View As the positioner steps apply gentle pressure to the body of the step motor at the points indicated 1 2 3 and 4 in figure 4 12 until misstepping occurs Assess qualitatively the pressure required to cause misstepping If the pressure is equal at all four points and or if a small region of free rocking exists in both axes this is acceptable proceed directly to step p Figure 4 12 Pressure Points on Positioner 102001A 4 17 NOTE Begin adjustment with step f if the positioner is being newly installed If the positioner is already in place but requires adjustment proceed directly to step m Loosen the positioner mounting block screws see figure 4 11 so the block can be moved Move one side of the block and then the other toward the spindle until the C clip at the end of the lead screw just comes into contact with the bearing at the end of the lead screw Push the positioner mounting block forward on one side about 1 32 inch and tighten the mounting screw on that side just enough to hold the block in place Push the other side of the block
80. egulated DC power from the system an enclosure and the regulated power supplies are not included Also since the system requirements determine the drive controller specifications the controller is not supplied by Micropolis The following OEM Floppy Disk Drives are described in this manual a Model 1015 MOD I b Model 1015 MOD II c Model 1016 MOD II MOD I drives have a track density of 48 tracks per inch TPI with a total of 35 tracks MOD II drives have a track density of 100TPI with 77 total tracks The difference in track density and total tracks results from using a differ ent lead screw in the positioner a different read write erase head and different components and adjustments on the PCBA Figure 1 1 Micropolis OEM Floppy Disk Drive typical 1 2 102001A Table 1 1 summarizes the specifications of the OEM Floppy Disk Drives TABLE 1 1 SPECIFICATIONS Physical without sleeve Height 3 3 8 in 86 mm Width 5 7 8 in 149 mm Depth 8 1 2 in 216 mm Weight 3 9 Ibs 1 77 kg Environmental Operating temperature 50 105 F 10 41 C Relative humidity 20 80 without condensation Power Dissipation Standby 8 watts Operating 16 watts Unformatted capacity per drive 1015 MOD I Single Density 110 Kbytes Double Density 220 Kbytes 1015 MOD II Wi Single Density 240 Kbytes Double Density 480 Kbytes 1016 MOD II 585 Kbytes Drive Characteristics Rotational speed 300 rpm Rotational latency 100
81. en replaced The positioner assembly has been replaced The positioner assembly has been adjusted for preload or azimuth Diskette interchange compatibility problems are encountered Procedure Apply power to the drive Apply a low signal to the MTRN interface line J1 pin 16 Insert the alignment diskette Micropolis P N 641 0590 1 Dysan P N 282 in the drive and load it Connect the oscilloscope to Single A TP3 and TP2 GND Single B TP5 and TP6 GND Set the vertical scale to 0 2V cm the time base to 20 ms cm Trigger external positive on the leading edge of the index sector pulse at Single A TP5 Single B TP2 Apply interface signals that cause the drive to be selected and positioned at Track 36 for a 100TPI MOD II drive or Track 16 for a 48TPI MOD I drive Observe the read signal see figure 4 7 Adjust the vertical scale so the peak amplitude of the larger lobe is five major divisions 5 cm and note the amplitude of the smaller lobe Figure 4 7 Cat s Eye Pattern for Radial Alignment Apply interface signals that cause the positioner to move off track by at least two tracks and then return to the track in step Note the amplitude of the smaller lobe Apply interface signals that cause the positioner to move off track in the other direction and return Again note the amplitude of the smaller lobe Acceptable track alignment is indicated if the peak to peak amplitude of the two lobes in steps f
82. erating Door Open Average Peak 12V 0 3A 1 0A 1 3A 5V 0 5A 0 5A 0 5A The 45V return and 12V return must be connected together at the power supply The drive chassis must be connected to the computer chassis or directly to earth ground 2 8 102001A SECTION III THEORY OF OPERATION 3 1 INTRODUCTION This section describes the operation of the drive First the drive mechanism is described followed by the signal interface and then the drive electronics PCBA both the Single A and the Single B PCBAs are described Each of these components is described in sufficient detail to assist fault isolation and troubleshooting 3 2 DRIVE MECHANISM The drive mechanism shown in figure 3 1 consists of the following elements Spindle Drive System Head Carriage Assembly c Positioner Control Mechanism Electrical and Mechanical Interlocks e Index Sensor Figure 3 1 Typical Drive Mechanism 102001A de A1 drive mechanisms use the same mechanical elements except a The lead screw has a pitch of 8 33 threads per inch for a 100TPI MOD II drive or 4 threads per inch for a 48TPI MOD I drive b A different magnetic head is used for 100TPI MOD II drives having narrower read write and erase gaps than the 48TPI MOD I drives 3 2 1 Spindle Drive System The spindle is driven by an integral DC motor AC tachometer which provides a closed loop velocity servo action via a belt which yields an 8 to 1 speed
83. erformed on line or off line a On line Apply power to the drive Apply a low signal to the MTRN interface line J1 pin 16 Off line Connect an ohmmeter between the yellow and green wires in the 12 position Molex connector on the drive mechanism b Press the receiver assembly until the motor turns on line or the ohmmeter indicates continuity off line The switch should activate before the top of the receiver is more than 1 8 inch below the slot in the front panel If necessary loosen the two switch mounting Screws and move the switch as required 4 12 POSITIONER MECHANICAL ADJUSTMENT The positioner mounting block incorporates adjustments for the preload of the lead screw against the spindle housing and for azimuth alignment of the axis of travel of the headgap The positioner mounting block adjustment is critical and complex and should only be performed if a The positioner is replaced or removed in order to install a new head b The positioner shows evidence of misstepping even after the Step Timing Section 4 5 has been adjusted 4 12 1 Procedure a Temporarily install the maintenance standoff at the rear of the drive mechanism so the mechanism does not rest on the step motor b Apply power to the drive c Manually move the lock bar diskette rear stop see figure 4 11 toward the rear of the drive until it locks simulating the existence of a diskette d Apply interface signals that cause the drive to b
84. ey It shows the model number part number and serial number of the drive These numbers should be quoted in all correspondence Drives shipped with the optional sleeve have the label attached to the back panel 102001A SECTION II INSTALLATION 2 1 INTRODUCTION This section provides information necessary for installing the drive Included are instructions for unpacking the drive and re packing the drive for shipment if necessary visually inspecting the drive installing the drive configuring multi drive disk systems and supplying power 2 2 UNPACKING THE DRIVE The drive is packed so as to minimize the possibility of damage during shipment Use the following procedure to unpack the drive and save ALL packing material in case it is necessary to re pack the drive for shipping a Place the shipping carton on a flat work surface b Carefully cut the sealing tape on the carton top open the top flaps c Remove and SAVE the six inch wide foam strip that covers the inner carton CAUTION Use extreme care when handling the inner carton the drive inside it is subject to damage if dropped d Carefully remove the inner carton and place it on the work surface e Cut the sealing tape on the carton top open the top flaps CAUTION When the drive and fiberboard base are removed from the carton the drive mechanism and circuit board will be exposed Handle VERY carefully f Lift the drive out of the carton SAVE the car
85. f the Receiver Assembly The latch mechanism should be replaced whenever the door cannot be latched or unlatched without difficulty i e if it is binding not latching or releasing properly etc The latch mechanism is accessible when the drive is removed and the PCBA is removed from the drive a Loosen the two bezel mounting screws b Slide the diskette ejector rearward until it latches c Move the bezel forward and upward until it clears the door handle then remove the bezel d The receiver may now be tilted upward to gain access to the two nuts securing the latch mechanism to the receiver see figure 6 8 Remove the two nuts and remove the latch mechanism Retain the spacer plate e Place the spacer plate and the replacement latch mechanism on the two mounting studs f Install and tighten the two mounting nuts g Apply a heavy coat of grease Micropolis P N 732 0001 to the entire latch mechanism h Lower the receiver to its normal position i Slide the bezel over the door handle then move the bezel down and rearward until it can be attached to the chassis with two screws and nuts 1020014 SECTION VII PARTS LIST 7 1 INTRODUCTION This section provides part numbers for various replaceable parts of the 1015 1016 Floppy Disk Drives Parts information for the Single A and Single B PCBAs are given on the respective schematics TABLE 7 1 OEM FLOPPY DISK DRIVE PARTS LIST Description Figure Ref
86. ge in state which fired 025 13 is still present at U23 pin 12 then U23 pin 9 will assume the same state U23 pin 12 will not change in less than 3 usec 1 3 for GCR for normal data transition U23 9 will not change state for a short duration noise pulse occurring at U26 7 since by the time the clock edge generated by the noise pulse is available at U23 11 the enable input at U23 12 is false Bidirectional One Shot The operation of exclusive OR gate U24 8 is identical to that described for U24 6 Every change in state of U23 9 every data transition will cause a high going pulse to be generated by U24 8 Element U25 5 a 0 9 usec one shot will fire for all transitions generating RDATA see figure 3 16 R69 and C39 determine the one shot pulse width U20 holds U25 reset whenever the drive is not selected or is in a write mode This prevents noise from being transmitted to the interface 3 5 5 Write Circuitry Sh 6 of Dwg 100164 The write circuitry consists of a power supply enable circuit a head select circuit write control logic write current drivers an erase current driver and the read write switch Figure 3 17 is a block diagram of the write circuitry HSLT POWER SUPPLY VOLTAGE DIVIDER ENABLE PSEN wBSY VOLTAGE _ WRITE POWER CONTROL DIVIDER A READ WRITE SWITCH WRITE CURRENT DRIVER TO READ CIRCUITS ERASE CURRENT DRIVERS OPTIONA
87. h actuator from entering the notch The mechanical interlock is a mechanism associated with the diskette ejector that prevents the door from closing if no diskette has been loaded into the drive receiver assembly It also ejects the diskette when the door handle is lifted after the door is opened 3 2 5 Index Sensor Index and sector information is sensed by a combination of a light emitting diode LED mounted on the receiver assembly and an index transducer photo transistor mounted in the platen Index to data adjustment is provided by moving the platen assembly 3 3 INTERFACE This section describes the interface signals and timing requirements from a general viewpoint This description applies to drives using either the Single A or the Single B PCBA Specific references are covered in the appropriate sections of the Single A and Single B PCBA descriptions Interface connector Jl is located on the drive electronics PCBA J1 provides the interface connection between the disk drive and the host controller The interface consists of 11 input lines and 5 output All interface lines are low true with the following logic levels True Logic Zero 0 0 4V False Logic One 2 5 5 25V 102001A 3 3 A maximum of four drives can be connected to one host controller with a daisy chain cable Termination resistors for the input lines are provided on the drive electronics PCBA for daisy chain connections they are installed in th
88. h movement in step h or i above tighten the azimuth clamp screws and repeat steps a through h of paragraph 4 8 1 until the difference of times is approximates zero NOTE After adjusting the azimuth the radial alignment see section 4 9 must be checked and adjusted if necessary Also after adjustment of the azimuth it is possible that misstepping will occur This should be checked using steps a through e of paragraph 4 12 1 k Proceed to the Circumferential Adjustment Paragraph 4 8 3 4 8 3 Circumferential Adjustment NOTE It is assumed that the conditions established by steps a through e of paragraph 4 8 2 are still in effect a Turn the drive on its side Loosen the two platen assembly mounting screws see figure 4 6 and move the platen use a screwdriver as a wedge between the tongue on the platen and slots in the chassis until the index to burst time is now the optimum 200 30 usec after reclamping the platen b After the azimuth and circumferential adjustments are both satisfactory remove the maintenance standoff 4 9 RADIAL ALIGNMENT Radial alignment ensures that the head is operating at the required radius for the particular track The alignment utilizes a cat s eye pattern on the alignment diskette centered on Track 36 for a 100TPI MOD II drive or Track 16 for a 48TPI MOD I drive 4 10 102001A Radial alignment should be checked whenever a b C d 4 9 1 1020014 The head has be
89. hed by potentiometer R66 and its associated components The reference voltage is developed by a voltage divider network consisting of resistor R65 and zener diode CR21 Potentiometer R66 is connected across the constant voltage source CR21 and in series with temperature compensating diode CR22 and resistor R67 The effect of this network is to produce a temperature compensated adjustable reference level at input U6 3 Resistors R70 and R72 form the feedback loop with a DC gain of 36 The output of U6 feeds the power amplifier drivers through DC coupling network R73 R74 Power Amplifier Circuits The power amplifier circuits consist of Darlington pair transistor Q5 current limiter circuit Q4 and associated components The operation of power amplifier driver Q5 is controlled by the state of the MOT signal This signal is coupled into the base of Q5 by diode CR23 When MOT is low CR23 conducts and the base of Q5 goes to 0 8V cutting off Q5 When MOT goes high CR23 is cut off allowing the base of Q5 to attain its operational value approx 1 4V Resistors R77 R75 and R76 and transistor Q4 form a feedback circuit that reduces the current surge caused by motor startup When the motor on command is received transistor Q5 goes into saturation and collector current would normally rise to a larger value since the motor is still stationary However the current feedback network consisting of 04 and its associated components will limit t
90. hile holding the receiver tab and the write protect switch remove the two switch mounting screws see figure 6 8 When the second screw is removed the nut plate on the inward side of the switch will be freed b Note the color coding of the wires at the three switch terminals then unsolder the wires and remove the switch C Observing the color coding noted in step b solder the three wires to the replacement switch d Hold the switch in place and insert two mounting screws through the receiver tab and through the switch Hold the nut plate against the screws and loosely run the screws into the nut plate Ensure the switch actuator is in the receiver notch e Perform the Write Protect Switch adjustment paragraph 4 13 102001A 6 17 6 14 DOOR OPEN SWITCH The door open switch is attached to a tab on the diskette ejector side of the receiver It is accessible when the drive is removed CAUTION When performing this procedure do not apply stress to the fragile tab to which the switch is mounted If the tab is damaged the entire receiver must be replaced paragraph 6 15 a While holding the receiver tab and the door open switch remove the two switch mounting screws When the second screw is removed the nut plate on the inward side of the switch will be freed PEN SWITCH OPEN SWITCH RECEIVER TAB SWITCH ACTUATOR Figure 6 13 Door Open Switch Details b Note the color coding of the wires at the three swit
91. his initial surge to a maximum of 0 8 amp Resistor R77 provides a convenient point to monitor the motor current Diode CR24 protects Q5 from inductive kickback caused by commutation L6 C37 C38 C39 and C40 provide filtering to prevent high frequency transients generated by the motor from propagating into the drive electronics through the power supply 3 10 102001A 3 4 3 Read Circuitry Sh 7 of Dwg 100072 The read circuitry processes the low level information from the read head during the read cycle reshaping it into a digital pulse stream Figure 3 8 is a block diagram of the read circuitry The 12V supplied to the elements in these circuits is filtered through L5 to provide additional noise isolation Voltage divider R47 R48 and filter capacitor C22 develop a reference voltage referred to as V1 of approximately 6V used in the circuits discussed below COMPARA TOR Figure 3 8 Single A Read Circuitry Block Diagram BI DIREC TIONAL ONE DIFFER ENTIATOR mE ui Ld SHOT SYSTEM FROM READ WRITE SWITCH CIRCUIT a Input Clamp The low level signal approx 1 5 mV pp from the read head is fed to differentiator U24 Input diodes CR18 and CR19 constitute a clamp circuit that prevents transients generated by the write circuit from propagating through the read circuits The junction of diodes CR18 and CR19 at V2 is held at approximately 6 7V This voltage is generated in voltage divider R
92. ier The amplifier consists of U27 and resistors R59 and R60 The gain of this stage is approximately 50 and can be adjusted by R59 The balanced output of this amplifier is AC coupled into a comparator by capacitors C32 and C33 and resistors R63 and R64 Resistors R61 and R62 center the output signal from U27 at the V1 reference potential Comparator The output of the amplifier is processed by low pass filter network R63 R64 C35 thus providing additional noise rejection for this stage Comparator U26 converts the essentially sinusoidal wave shape input into a square wave Figure 3 16 shows this waveform conversion and timing Digital Noise Filter The output of comparator U26 is connected to one shot U25 13 via exclusive OR gate U24 6 and to flip flop U23 9 These three logic elements and their associated components form a digital noise filter that rejects short duration pulse type noise The filter will reject noise pulses of a duration of less than 3 usec approx in an MFM Model 1015 version of the PCBA or less than 1 3 psec in a GCR Model 1016 version Since U24 6 is an exclusive OR gate a short duration high going pulse will be generated at 024 6 for every change in state of 026 7 This is due to the delay at U24 pin 5 created by R66 and C36 U25 13 will therefore fire for every transition R67 and C37 determine the 3 23 one shot pulse width U23 pin 11 will clock at the end of 3 usec 1 3 usec for GCR if the chan
93. is a mechanical stop on the lead screw that prevents the head from moving behind track zero The track zero switch and zero stop should be checked whenever a 0 c 102001A The positioner has been replaced The head has been replaced The switch has been replaced Radial alignment has been performed or unsuccessfully attempted The head carriage is heard hitting against the mechanical stop 4 10 1 Uc Procedure Apply power to the drive T Apply a low signal to the MTRN interface line Jl pin 16 Insert a work diskette in the drive and load it Apply interface signals that cause the drive to be selected and alternately positioned to Track 0 and Track 1 with a turnaround time of approximately 200 ms Connect the oscilloscope to Single A channel 1 to the SBSY signal at U12 4 channel 2 to the track zero switch output at U2 3 Single B channel 1 to the SBSY signal at TP8 channel 2 to the track zero switch output at U2 4 Set the vertical scale for both channels to 2V cm Set the time base to 2 ms cm Trigger on the positive going edge of the channel 1 input signal SBSY Observe the waveform on channel 2 Figure 4 9 shows alternate sweeps of the signal The track zero switch and stop settings are acceptable if the high to low and low to high transitions occur within two major divisions 4 ms of each other on alternate sweeps If so skip step g and proceed directly to step h if
94. j 100165 E APPLICATION DO NOT SCALE DRAWING gt SALE 2 sur or ASSY 100163 VERSION CHARACTERISTIC W sa IOO TPI GCR ee 48 TPI NE555 2N4402 1N4446 HEADER HEADER DUAL HEAD 410 0555 4 300 4402 8 200 4446 7 680 0506 5 680 0505 7 6 19K 195 I9 6K 1 54 2 48 TPI MFM HEADER SINGLE HEAD 680 0505 7 T IOO TPI MFM NE555 2N4402 IN4446 Lege HEADER o 56 7 IOOTPI MFM SINGLE HEAD VERSION 9G TPI MFM 96 TPI NE ss HEADER HEADER DUAL HEAD 410 0555 4 300 4402 8 200 4446 7 680 0506 5 680 0505 7 a C L at free I sson PART NO REF DESIGNTION 100 0000 8 100 1 000 7 100 1500 6 100 1800 O 100 2200 2 100 3300 9 00 4700 3 100 5600 O 100 6800 5 100 1001 5 100 2700 100 1501 4 100 1801 8 00 2201 0 100 6801 3 100 1002 3 100 1202 9 100 2202 8 100 2702 7 100 4702 5 100 1003 100 1503 0 101 101 0010 5 0680 5 105 1741 5 105 6191 8 105 1002 2 105 1962 7 150 2002 9 15072001 7 151 5001 6 R42 52 53 W5 7 10 86 RI5 51 Rl 6 57 58 RI9 15 14 54 55 60 20 50 66 68 R65 80 81 63 64 R4I R47 R18 25 34 79 82 84 R7I Ro6 33 R46 R43 61 62 R4 R2 R29 37 44 45 6974 75 R27 28 R484 49 R 12 17 78 RIG R70 R83 R7 8 9 10 TABLET CRIO CRI3 UB Q5 CRI9 CR20 CR2I EI IOOTPI GCR 555 2N4402 iN4
95. l occur If necessary add or remove shim washers on the clamp support plate spacers so clearance does exist Unload and reload the diskette several times and check that clearance still exists 4 20 102001A 102001A 4 15 DISKETTE REAR STOP The diskette rear stop see figure 4 11 positions the diskette with respect to the spindle The rear stop also serves to eject the diskette when it is being removed This adjustment should be checked whenever a There is evidence of uneven wear on the diskette b The diskette cannot be fully inserted in the drive or does not ejec properly 4 15 1 Procedure a Remove the PCBA from the drive and reconnect it using extender cables as necessary b Apply power to the drive c Apply a low signal to the MTRN interface line Jl pin 16 Insert a diskette in the drive If it is close to its correct position load it and proceed to step If it is significantly out of position do not load it but still proceed to step e e Loosen the rear stop adjustment screw and slide the rear stop on the lock bar so that with the diskette jacket seated against the stop the opening in the center of the jacket is centered around the clamp f Tighten the rear stop adjustment screw g Unload the diskette then reload it and recheck the adjustment SECTION V TROUBLESHOOTING 5 1 INTRODUCTION This section provides a troubleshooting chart to aid in isolating a fault symptom to a specific circuit componen
96. losophy operator troubleshooting and maintenance test equipment and tools required and spare parts ordering procedures Section II Installation provides procedures for unpacking the drive installing the drive configuring multi drive systems and supplying power Section III Theory of Operation provides a detailed description of the disk drive covering the drive mechanism the interface and each version of the drive electronics board Section IV Tests and Adjustments provides procedures to test and adjust all parameters of the disk drive Section V Troubleshooting provides information to assist in isolating a fault to a replaceable component or subassembly in a logical manner Section VI Removal and Replacement Procedures provides step by step instructions for replacing assemblies subassemblies or components of the disk drive Section VII Parts List provides part numbers of the replaceable parts of the disk drive Section VIII Assembly Drawings and Schematic Diagrams provides component layout drawings and engineering schematic diagrams for the drive electronics boards used in the OEM Floppy Disk Drives 102001 ded 1 3 DESCRIPTION OF DRIVES Each Micropolis OEM Floppy Disk Drive see figure 1 1 consists of a drive mechanism and a drive electronics PCBA A protective mounting sleeve not shown in figure 1 1 is optional Since the drives are intended to be mounted within an OEM system and receive r
97. ly a coat of grease Micropolis P N 732 0001 to the lead screw p Manually rotate the lead screw The head carriage should move smoothly on the lead screw but not be so loose that the spring plate does not hold the carriage against the lead screw q Perform the following tests and adjustments in the order listed Procedure Paragraph Positioner Mechanical Adjustment 4 12 Radial Alignment 4 9 Circumferential Azimuth Alignment 4 8 Track Zero Switch and Zero Stop 4 10 Radial Alignment second time 4 9 Read Amplifier Gain 4 6 Head Compliance 4 7 r Loosen the screw securing the positioner protection bracket turn the bracket to its normal position where it will prevent the lead screw from coming out of the spindle housing bearing then tighten the screw 6 7 HEAD CARRIAGE The head is supplied permanently mounted in the head carriage Since the head carriage is removed and installed along with the positioner follow the procedure given in paragraph 6 6 to replace the head carriage 6 10 102001A 6 8 HEAD LOAD SOLENOID The head load solenoid is accessible when the drive is removed a Remove the head load solenoid mounting screw then slide the head load solenoid out of the drive mechanism far enough to disconnect the wires from the solenoid terminals Then remove the head load solenoid It may be necessary to clip the tie wrap holding the head cable to the chassis to perform this step DOOR OPEN SPRING HEAD WRITE PROTECT
98. min 48TPI MOD I 26 ms max 24 ms min Figure 4 4 Positioner Step Timing Waveform If these limits are not met adjust the step timing using Single A potentiometer R10 Single B potentiometer R3 Adjust the timing to 100TPI MOD II 22 5 ms 48TPI MOD I 25 0 ms For reference the duration of the individual step times can be observed at U12 4 on the Single A PCBA or TP8 on the Single B PCBA These are shown in figure 3 12 for correctly adjusted step timing The individual step times are not adjustable if they are out of tolerance troubleshoot to the defective component 4 5 4 6 READ AMPLIFIER GAIN The read amplifier gain control sets the Signal level at the output of the amplifier chain The adjustment should be checked whenever a The head is replaced b The PCBA is replaced c Components in the R W switch differentiator or amplifier circuits are replaced 4 6 1 Procedure a Apply power to the drive b Apply a low signal to the MTRN interface line Jl pin 16 c Insert a work diskette in the drive and load it d Apply interface signals that cause the drive to be selected and an all ones pattern to be written on track zero of the diskette e Connect the oscilloscope to Single A TP3 and TP2 GND Single B TP5 and TP6 GND Set the vertical scale to 0 5V cm and the time base to 10 usec cm Trigger internally f Measure the peak to peak amplitude of the read signal The signal sho
99. n no account should the scheme rely on the plastic bezel for support The three holes in the chassis that are used to hold the drive to the fiberboard shipping base are NOT to be used for mounting the drive Use the two front and either one of the rear plastic mounting nuts on the chassis edges For drives with the optional protective sleeve use the outside two holes on either side or the three holes on the sleeve bottom or preferred the two front and either one of the rear holes that secure the sleeve to the drive chassis See figure 2 1 for details Spacers against the sleeve should be at least 0 5 inch outside diameter Use care that mounting screws do not protrude more than 0 2 inch into the drive mechanism The holes in the base chassis to which the drive is to be mounted must have sufficient clearance to allow for tolerances and thermal expansion This also precludes the use of flat head screws Mounting brackets should be made of 0 060 inch thick min steel attached to the base chassis and with holes large enough that when all screws are tight stress is not communicated to the drive a 3 5 72 02 14 53 3 22 2 55 8 18 DRIVE CHASSIS 85 J 2 16 I PLASTIC MOUNTING NUTS 6 32 2 PER SIDE ON DRIVE CHASSIS USE BOTH FRONT MTG SUGGESTED PANEL OPENING NUTS AND EITHER ONE REAR MTG NUT FOR EXTERNAL MOUNTING 010 010 5 825 gos BY 3 305 goo INCHES 025 025 14 795 912 BY 8 395
100. nd U10 6 is enabled After the delay the drive ready RDY signal is produced This delay allows the drive motor to reach operational speed before proceeding 3 5 7 5 Drive Motor Initialization Sh 4 of Dwg 100164 To insure registration of the media whenever a diskette is inserted into the drive the drive motor is automatically turned on for two seconds independent of the state of MTRN The delay circuit consisting of U9 10 R11 R13 C5 C6 and U10 2 generates a high MOT signal for two seconds after DOOR goes low 3 30 1020014 102001A SECTION IV TESTS AND ADJUSTMENTS 4 1 INTRODUCTION This section provides information on testing a drive and if necessary adjusting the electrical and mechanical parameters The tests and adjustments should be performed in an order dictated by the operating condition of the drive this may or may not be the order in which they are presented in this section In general the test requirements for the different drive configurations are the same When the test requirements differ the relevant paragraphs specify those differences Figures 4 1 and 4 2 show the location of PCBA mounted components referenced in these procedures for the Single A PCBA and the Single B PCBA respectively Tools and test equipment required are listed in Section 1 4 2 ADJUSTMENT PHILOSOPHY Acceptable limits are specified in each test and adjustment procedure taking into account the assumed accuracy of the te
101. nderstanding of the operation of a circuit or a mechanical or electrical component is desired see the Theory of Operation in Section 3 The circuit descriptions reference the Assembly Drawings and Schematic Diagrams in Section 8 c If necessary test the suspected circuit or mechanical assembly See Section 4 Tests and Adjustments Also using Section 4 it may be possible to perform an adjustment to eliminate the fault d Order a replacement component subassembly or assembly See Section 7 Parts List e Replace the component subassembly or assembly See Section 6 Removal and Replacement Procedures f Adjust and or test the circuit or mechanism after replacing the part See Section 4 Tests and Adjustments 1 8 SPARE PARTS Section 7 provides part numbers for the replaceable parts of the OEM Floppy Disk Drives Information on recommended spares levels for field engineers and for repair depots can be obtained from Micropolis Customer Service These levels should be maintained to reduce down time Routine orders for spare parts should be placed through Order Entry not Customer Service Orders for routine spares are treated and scheduled in the same manner as orders for disk drives accessories etc Emergency spares will be shipped within 24 hours and will not be discounted Emergency spare orders should be placed with Customer Service _ An identification label is attached to the underside of the chassis near the large pull
102. nnected to the last connector on the cable i e the furthest from the controller to provide proper termination 2 7 2 Master to Add On Conversion To convert a master drive to an add on drive remove the terminators as follows a Locate the terminator resistor pack U15 on a Single A PCBA U17 on a Single B PCBA b With a small flat blade screwdriver carefully pry the resistor pack from its socket The resistor pack should be saved in case it is desired to convert the drive back in the future 2 7 3 Address Changing To change the drive address reconfigure the address comparison logic as follows a Locate address jumper locations Wl through W4 on the PCBA Model 1015 1016 drives are shipped with Wl installed Only ONE of the jumpers W1 through W4 may be installed on a PCBA b Remove the jumper from the socket Replace the jumper in the socket for the desired address as follows Drive Install Address T is W2 W3 W4 1 W1 W3 W4 W1 W2 W4 3 W4 W1 W2 W3 102001A Gr 2 8 SUPPLYING DC POWER The 1015 1016 drives require user supplied DC power 5V and 12V regulated DC power is supplied to 10 pin connector J5 on the drive PCBA The mating connector is Molex Part No 22 01 2101 Pin assignments are v ON O Q W FI Connection Not used Key 12V return 12V Not used 5V return 5V Not used Not used Not used e Current requirements are as follows Standby Op
103. o the chassis then cut the tie wraps Separate the receiver wires from the remainder of the drive mechanism wires With the original receiver assembly still attached to the drive mechanism by wires position the replacement receiver assembly so that its wires can be routed in the same manner as the original s Select a wire from the original receiver and trace it to the PCBA connector Insert a pointed tool such as a scribe into the connector window adjacent to the selected wire and press the metal tab that locks the contact in the connector body Slide the contact toward the wire end of the connector then gently pull on the wire while using the scribe to push the contact out of the connector body Select the corresponding wire from the replacement receiver align its contact with the connector body socket metal tab toward window and push the contact into the connector until seated Repeat steps i through 1 for all remaining receiver wires Ensure the door open spring is in place then position the replace ment receiver in the right pivot with the left side up Install the left pivot post in place over the receiver pivot Install the left pivot post mounting screw do not overtighten Slide the diskette ejector rearward until it latches Slide the bezel over the door handle then move the bezel down and rearward until it can be attached to the chassis with two screws and nuts Install tie wraps at locations noted in
104. on provides detailed procedures for replacing subadsemblies and parts of the drive Components are replaced at their spared level i e a subassembly is replaced as a unit Tests and adjustments in Section 4 are referenced as applicable for each replacement procedure Tools required for these procedures are listed in Section 1 All procedures assume that the sleeve if present has been removed 6 2 DISK DRIVE REPLACEMENT Use this procedure to replace the entire disk drive consisting of the drive mechanism and the drive electronics PCBA a Disconnect DC power at J5 and the interface cable to the controller at Jl on the PCBA b Remove the screws that attach the disk drive to the base chassis or brackets Remove the disk drive through the panel opening c Insert the replacement drive through the panel opening from the front d Reattach the drive to the base chassis or mounting brackets See section 2 6 for more information e Reconnect the interface cable at Jl and the DC power at J5 MOUNTING NUTS 2 each side Figure 6 1 Mounting Nut Location 102001A 6 1 6 3 DRIVE ELECTRONICS PCBA The drive electronics PCBA is mounted on top of the drive mechanism The replacement procedure is the same for the Single A or Single B PCBA a Note the location and orientation of the four drive to PCBA connectors at J3 and J4 on the PCBA then disconnect the four connectors CAUTION During the next two steps handle the head
105. on0 a LIL J6 TO FROM RE o READ WRITE HEAD MOUNTING SCREW 22 222 ee HOLE Z MICROPOLJIS J5 TERMINATION TP4 TP3 TP R54 1 RESISTORS READ GAIN POWER REMOVABLE Figure 4 1 Single A PCBA Mounted Components FOUR DRIVE TO PCBA CONNECTORS R3 SWITCHES AND POSITIONER TRANSDUCER MOTOR TP7 TIMING TPS R72 MOTOR SPEED LED AND POSITIONER PHOTO TRANSISTOR MOUNTING SCREW HOLE Ji INTERFACE UNIT SELECT JUMPERS SELECT INDICATOR J2 NOT USED MOUNTING SCREW J6 TO FROM HOLE z READ WRITE HEAD J5 5 3 0 2 Annand REGULATED 8 5 d DC POWER ORo erod aureus s TPL TERMINATION RESISTORS TP2 TP3 TP4 R59 TP9 REMOVABLE READ GAIN Figure 4 2 Single B PCBA Mounted Components 4 2 102001A e Illuminate the strobe disk with a fluorescent lamp Observe the outer strobe pattern for 60Hz lamp power or the inner strobe pattern for 50Hz power and time the pattern rotation speed Ideally the pattern will be stationary a maximum of 9 revolutions per minute clockwise or counterclockwise is acceptable g If necessary adjust potentiometer R66 on the Single A PCBA or R72 if a Single B PCBA for a stationary strobe pattern 4 3 2 Counter Method a Apply power to the drive b Apply a low signal to the MTRN interface line J1 pin 16 c Insert a SINGLE HOLE soft sectored work diskette in the drive and load it d Apply interface signal
106. or removed A jumper in one of the positions Wl 2 W3 W4 causes the drive selection logic to respond to the corresponding drive select input line DS1 DS2 DS3 or DS4 The appropriate select line is terminated by RN1 and received by 010 1 The select signal gates the output signals directly via drivers 01 6 01 8 01 11 and U1 3 and indirectly via U20 8 on Sh 7 of Dwg 100164 for the read data signal The select signal also drives a LED panel indicator via driver U9 4 to indicate that the drive is selected 3 5 3 Motor Control Circuit Sh 8 of Dwg 100164 The motor control circuit is a closed loop servo which controls the spindle drive system The spindle drive consists of a DC motor and AC tachometer mounted on a common shaft The DC motor shaft rotation is converted by the tachometer to an AC signal whose amplitude is proportional to the speed of the motor This feedback signal is rectified and filtered to produce an equivalent DC signal An operational amplifier compares the feedback signal with a reference level generated on the PCBA The net output from the operational amplifier drives a power amplifier which in turn powers the DC motor Figure 3 14 is a block diagram of the motor control circuit a Rectifier and Filter The AC tachometer signal enters the Single B PCBA at J4 14 and 15 Diode CR30 and resistor R70 form a half wave rectifier whose output is filtered by capacitor C44 The filtered signal is applied to th
107. orarily move the PCBA out of the way see paragraph 6 3 but do not cut the head cable tie wraps Prior to lubrication the stepper motor lead screw should be cleaned Wipe the lead screw with a lint free cloth lightly moistened with isopropyl alcohol CAUTION Do not contaminate the magnetic record ing head or the head load pad with lubricant Damage to the diskette s recording surface can be caused by lubricant deposited on the head or head load pad Lubricate the lead screw and the part of the head carriage that rides on the platen with a thick coat of Saunders Magnalube Micropolis P N 732 0001 6 1 6 3 Latch Mechanism Lubrication To gain access to the latch mechanism it will usually be necessary to first remove the drive from the system enclosure see paragraph 6 2 for procedure To ensure smooth positive action of the door latch mechanism apply a heavy coat of Saunders Magnalube Micropolis P N 732 0001 6 to the entire latch mechanism 1 7 CORRECTIVE MAINTENANCE Corrective maintenance consists of isolating a fault to a defective or misadjusted assembly or component replacing or adjusting the assembly or component and verifying that the repair has eliminated the fault The following suggested sequence will help to make the most effective and efficient use of this manual a Isolate the malfunction to the faulty assembly subassembly or component See the Troubleshooting Chart in Section 5 b If amore thorough u
108. orough guide for qualified service personnel to troubleshoot the disk drive 1 4 2 Dealer Service Centers Micropolis dealers and OEMs that have received formal training on the theory of operation and maintenance of Micropolis equipment and that possess adequate test equipment and spare parts are designated as Micropolis Service Centers These Service Centers are best able to provide high quality and timely warranty and nonwarranty service on Micropolis products 102001A 1 5 1 4 3 Micropolis Repair Depot Micropolis maintains a fully equipped repair depot which provides warranty and nonwarranty repairs and emergency spares support Contact Micropolis Customer Service to obtain a Return Goods Authorization RGA prior to returning any drive for repair 1 5 MAINTENANCE EQUIPMENT REQUIRED The following tools test equipment and special items are required for maintaining and or servicing Micropolis OEM Floppy Disk Drives Where a manufacturers part number is given equivalent equipment may be used a Tools 3 16 inch nut driver 1 4 inch nut driver Screwdriver Phillips 1 Tweezers Clause 231 7 64 inch hex driver 7 64 inch hex key long handle 3 32 inch hex key Spring Hook Set National Camera S1390 1 4 inch combination wrench 5 16 inch box end wrench 3 8 inch box end wrench Pot screwdriver Bouvus H 90 Spring scale 0 10 165 Cotton swabs b Test Equipment Oscilloscope Tektronix 453 Digital multimeter Simpson 46
109. r circuit Troubleshoot head Intermittent diode s switch diodes in read write head switch circuit Troubleshoot or replace PCBA Erase current driver in write circuitry has incorrect delays x Troubleshoot or replace PCBA Failure in write circuitry on PCBA 5 4 102001A TABLE 5 1 TROUBLESHOOTING CHART cont Write errors cont Drive is always or never write protected Diskette incompati bility between drives Defective head Write protect switch failure Failure in write protect circuitry on PCBA Drive motor speed incorrect Excessive instan taneous speed variation ISV Circumferential Azimuth alignment out of adjustment Radial alignment out of adjustment Marginal head or marginal read write circuits in one or both drives 5 5 If replacing the PCBA does not correct the problem replace the head Check ISV or replace drive belt and motor Check adjust replace switch Troubleshoot or replace PCBA Check adjust motor speed Check Check adjust circumferential azimuth alignment Check adjust radial alignment Troubleshoot read write circuits or replace PCBA If problem persists replace head SECTION VI REMOVAL AND REPLACEMENT PROCEDURES 6 1 INTRODUCTION This secti
110. rings The spindle assembly is accessible when the drive is removed and the PCBA and clamp assembly are removed 6 12 102001 102001A a Remove the drive belt see paragraph 6 4 for procedure b While holding the large pulley with one hand remove the retaining screw then remove the large pulley c Remove the clamp assembly see paragraph 6 9 for procedure d Remove the two or three spindle housing mounting screws and remove the spindle housing and spindle from the drive mechanism by raising the housing from the chassis and sliding it toward the bezel toward the front of the drive until the lead screw is free of the bearing in the housing See figure 6 10 SPINDLE HOUSING SPINDLE HOUSING LEAD SCREW BEARING J SPINDLE Figure 6 10 Spindle Housing Details e Slide the replacement spindle housing with replacement spindle over the end of the lead screw Align the spindle housing mounting holes and key with the respective holes in the chassis f Install the spindle housing mounting screws and tighten them securely g Replace the clamp assembly see paragraph 6 9 h Place the large pulley with strobe disk against the spindle and install the retaining screw i Replace the drive belt see paragraph 6 4 j Perform the following tests and adjustments in the order listed Procedure Paragraph Clamp Support Plate 4 14 Circumferential Azimuth Alignment 4 8 Radial Alignment 4 9 Track
111. roximately 400 usec after the write control signal has been activated and off 800 usec between head write gap and erase gap using a tunnel erase head When the circuits are not in the write mode U14 3 is low and the output of erase driver U15 3 is high When the write operation is initiated U14 3 goes high The output of driver U15 does not follow the change of state until delay network R21 C10 times out approxi mately 400 usec At this time U15 senses the high state of U14 3 and U15 3 goes low This condition causes the erase current to flow from the center tap of the head through the erase winding and diode CR18 The amount of erase current is determined by the value of R35 At the conclusion of the write operation U14 3 goes low As in the previous paragraph the output of U15 does not follow this state until another delay circuit consisting of R22 and C10 times out approximately 800 usec At the end of that period U15 3 goes high and the erase current stops flowing Diode CR8 absorbs the inductive emf when the head winding current stops The operation of U8 and its associated circuitry within the dashed lines is identical to that described above This circuitry is only present for double head drives Jumper W9 is required on single headed versions of the PCBA to prevent Q3 from switching to a read mode prior to the conclusion of the erase operation Read Write Switch The read write switch consists of diodes 16 CR17 CR1
112. s that cause the drive to be selected and positioned at track zero The head should be loaded at this time e Connect a counter timer to the index sector test point Single A TP5 and TP2 GND Single B TP2 and TP6 GND f The index pulse period should be in the range of 194 to 206 ms If not adjust R66 on the Single A PCBA or R72 on the Single B PCBA for a period of 200 ms 4 4 INSTANTANEOUS SPEED VARIATION Instantaneous speed variation ISV is the change of rotational speed over a short period of time The period used in this test is approximately one and one half revolutions of the large pulley Factors that cause ISV include worn motor bearings a defective motor or a defective drive belt ISV should be checked whenever a The drive motor is replaced The PCBA is replaced Any drive motor circuit components are changed The drive belt is replaced D Diskette interchange compatibility problems are encountered 4 4 1 Procedure Apply power to the drive Apply a low signal to the MTRN interface line J1 pin 16 Insert a work diskette in the drive and load it Apply interface Signals that cause the drive to be selected and an all ones pattern to be written on track zero of the diskette a o oco go 1029914 4 3 e Connect the oscilloscope to Single A TP3 and TP2 GND Single B TP4 and TP6 GND Set the vertical scale to 0 2V cm the time base to 0 5 usec cm then adjust the time b
113. section 3 3 The Single A PCBA consists of the following functional elements Interface Circuits Motor Control Circuit Read Circuitry Write Circuitry Positioner Control Circuit Miscellaneous Control Circuits D a OC o These elements are shown in block diagram form in figure 3 6 The paragraphs POSITIONER CONTROL AND STEP MOTOR DRIVERS INTERFACE CIRCUITS SWITCHES TRANSDUCER AND SOLENOID DRIVE ASSEMBLY WRITE ENABLE SERIAL READ DATA RD MTRN MOTOR DRIVE Figure 3 6 Single A Overall Block Diagram 3 8 102001A that follow provide a detailed explanation of each functional element The circuit descriptions are supported by block diagrams detailed schematic diagrams are located in Section 8 of this manual The schematics are referenced by drawing and sheet number to facilitate their use 3 4 1 Interface Circuits Sh 2 of Dwg 100072 The interface circuits consist of line receivers input terminators line drivers and drive selection logic Input signals are terminated by 220 330 ohm terminator pack U15 As discussed in paragraph 2 7 1 add on drives have the terminator removed A jumper in one of the positions W1 W2 W3 or W4 causes the drive selection logic to respond to the corresponding drive select input line DS1 DS2 DS3 or DS4 The appropriate select line is terminated by R1 and received by 016 2 The select signal gates the output signals directly via drivers 01
114. sed by the write current driver circuit When both set and clear were low both outputs were in a high state The flip flop is connected in such a manner that each time a write pulse occurs the flip flop toggles on the trailing edge of that pulse The two complementary outputs of 019 are coupled by power drivers into the read write head through resistors R30 and R31 As the flip flop toggles power drivers U20 10 and U20 8 are energized sequentially thus alternately driving a current through the two halves of the read write head Diodes CR9 and CR10 are used to isolate the write circuits from the head during the read operation to increase noise immunity Resistors R28 and R29 ensure that CR9 and CR10 are back biased when the write operation is concluded Erase Current Driver Resistors R25 and R26 diode CR7 capacitor C16 and timer U13 combine the functions of an erase current driver with a delay generator that generates two different delays from the leading edge and the trailing edge of the input waveform This causes the erase current to be switched on approximately 400 usec after the write control signal has been activated and off 800 usec after the control signal is removed to accommodate the time delay between head write gap and erase gap using a tunnel erase head When the circuits are not in the write mode U20 12 is low and the output of erase driver U13 3 is high When the write operation is initiated U20 12 goes high The output
115. sert the alignment diskette Micropolis P N 641 0590 1 Dysan P N 282 in the drive and load it e Connect the oscilloscope as specified in paragraph 4 8 1 step d Apply interface signals as specified in paragraph 3 8 1 step e NOTE Step f below is performed to ensure that steps g through j can be achieved f Loosen two platen assembly mounting screws see figure 4 6 and temporarily move the platen use a screwdriver as a wedge between the tongue on the platen and slots in the chassis until the index to burst time after reclamping the platen is 300 usec Too much force can damage the polycarbonate platen material TRACK ZERO SWITCH BRACKET MOUNTING SCREWS SWITCH ACCESS SLOT AZIMUTH CLAMP SCREWS MAINTENANCE STANDOFF PLATEN ASSEMBLY ACCES MOUNTING SCREWS SLOT Figure 4 6 Drive Adjustment Access 102001A nz g Loosen two positioner azimuth clamp screws visible from below at the rear of the step motor see figures 4 6 and 4 8 that hold the positioner spring plate to the mounting block h If the time measured in paragraph 4 8 1 step f Track 5 or Track 1 exceeds that of 4 8 1 step h Track 76 or Track 35 the positioner should be moved toward the drive motor This will decrease both of the times but will also tend to equalize them i If the time measured in 4 8 1 step f is less than that of 4 8 1 step h the positioner should be moved away from the drive motor j After eac
116. st equipment specified If the measured value of any parameter is within the acceptable limits NO ADJUSTMENT should be made If the measured value is outside of the acceptable limits the accompanying adjustment should be performed 4 3 DRIVE MOTOR SPEED Drive motor speed should be checked whenever a The motor is replaced b The PCBA is replaced c Any drive motor circuit components are replaced d Diskette interchange compatibility problems are encountered Two methods are available for checking the drive motor speed These are a Using the strobe disk attached to the large pulley on the drive note that earlier drives do not have this strobe disk or b Measuring the period between index pulses using a counter 4 3 1 Strobe Method a Apply power to the drive b Apply a low signal to the MTRN interface line J1 pin 16 c Insert a work diskette in the drive and load it d Apply interface signals that cause the drive to be selected and positioned at track zero The head should be loaded at this time 4 1 FOUR DRIVE TO PCBA CONNECTORS LED AND SWITCHES AND POSITIONER PHOTO TRANSISTOR TRANSDUCER MOTOR TP6 R66 MOTOR SPEED Ce Sr 1649 2 Ga a MOUNTING SCREM olar ERAR SS HOLE T 6278 999109 3 U gt Ck2 100070 01 00 SELECT D INDICATOR J1 INTERFACE R10 UNIT SELECT POSITIONER TIMING JUMPERS J2 spy NOT USED C900 OG o
117. t or subassembly In most cases there is a paragraph reference for more information or a detailed procedure TABLE 5 1 TROUBLESHOOTING CHART Select Interface cable Reverse cable 3 3 indicator reversed at one Drive motor Drive controller Check interface 3 3 does not not connected to cable Irotate when drive diskette is inserted and No power to drive Check for 5V at door is J5 7 and for 12V latched down at J5 4 on the 71 16 low PCBA Drive motor is Measure motor current defective voltage across 1 ohm current limiting resistor R77 Single A or R83 Single B Nominal head loaded motor turning current is 300 to 500 ma rising to 700 ma with motor stalled Replace motor if defective Drive motor Troubleshoot drive Circuits on PCBA motor circuits or are defective replace PCBA Door open switch is Check replace defective switch 102001A 5 1 npo 5 1 TROUBLESHOOTING CHART cont Symptom Possible Cause Drive motor Intermittent connector Repair replace rotates much on drive motor connector more rapidly than 300 rpm and cannot be adjusted Reference Defective drive motor open tachometer winding Replace drive motor Troubleshoot servo circuit or replace PCBA Failure in drive servo circuit on PCBA Head load solenoid open Head will not Replace solenoid load Tro
118. tion occurs with a feeler gauge of 0 035 inch 4 14 CLAMP SUPPORT PLATE The clamp support plate see figure 4 11 provides the mounting surface for the clamp The clamp shaft must be centered in the support plate hole such that the shaft does not touch the support plate either on the side or via the C clip which secures the clamp shaft when the receiver assembly is in the loaded position This adjustment should be checked whenever a The support plate is removed for any reason b The spindle assembly is replaced There is evidence of severe diskette wear at the center in the clamp area 4 14 1 Procedure a m a O C Remove the PCBA from the drive and reconnect it using extender cables as necessary Apply power to the drive Apply a low signal to the MTRN interface line Jl pin 16 Insert a diskette in the drive and load it Clearance should exist between the clamp shaft and the clearance hole in the clamp support plate see figure 4 13 If clearance does not exist adjust per steps f and g CLAMP CLAMP SUPPORT SHAFT PLATE Figure 4 13 Clamp Support Plate Clearance Loosen the clamp support plate mounting nuts Move the plate as required to center the clearance hole around the clamp shaft Retighten the nuts With a diskette loaded clearance should also exist between the clamp C clip and the top of the support plate to ensure that full clamp spring force exists Otherwise diskette slippage and wear wil
119. ts are effectively isolated from the read write head When the read mode is selected 03 is cut off since the WRT signal is high at U18 9 Under these conditions the circuit stabilizes with CR14 and CR15 cut off and diodes CR12 CR13 CR16 and CR17 conducting The anodes of CR12 and CR13 are at approximately 6V since they are connected through the low impedance head to voltage divider R36 R38 Approximately 0 25 ma is supplied through resistors R45 and R46 and diodes CR16 and CR17 About 0 5 ma is drawn through R39 and R40 Thus each of the four diodes have approximately 0 25 ma of current flowing through them In this way the diode bridge provides a low impedance path for the head signal to differentiator U24 Sh 7 of Dwg 100072 1020014 3 15 3 4 5 Positioner Control Circuit Sh 3 of Dwg 100072 The positioner control circuit shown in block diagram form in figure 3 11 generates signals which cause the stepper motor to move the head from track to track in response to a step command Four sequential signals designated phase 1 1 phase 2 2 phase 3 3 and phase 4 44 are applied to the stepper motor drive circuits to cause track to track positioning Initially the system is in the hold state with 94 on If a step in command is received the signal sequence 1 2 3 4 is generated If a step out command is received the signal sequence 3 2 61 4 is generated GATED OSCILLATOR STEP O WEN SEQUENCER
120. ubleshoot solenoid logic and driver circuit or replace PCBA Failure in head load solenoid circuit on PCBA Troubleshoot driver circuit or replace PCBA Solenoid driver shorted Head will not unload Remove obstruction Solenoid binding to free movement Stepper motor defective Positioner missteps head ends up at wrong track Replace positioner Positioner binding Readjust positioner Troubleshoot positioner circuits or replace PCBA Failure in positioner circuits on PCBA Insufficient clamping force No gap between C clip and top of support plate when door is closed Diskette slips after door is closed Replace plate to ensure a minimum gap of 0 005 when door is shut anda diskette is in place 102001A Diskette jams or miscenters Crunching sound when closing drive door Door will not latch or unlatch Soft non permanent read errors Clamp miscentered Oxide on clamp or spindle Diskette rear stop out of position Clamp defective Not enough lubricant on the latch or on the bezel latch tabs Defective latch mechanism Degraded surface on diskette Head dirty or contaminated with oxide Head load pad is dirty or contaminated with oxide Excessive instan taneous speed variation ISV Excessive pulse type noise in
121. uld be in the range of 1 0V to 2 0V peak to peak If not adjust potentiometer R54 on the Single A PCBA or R59 on the Single B PCBA for a read signal amplitude of 1 5V peak to peak 4 7 HEAD COMPLIANCE The head compliance test checks for the presence of the correct contact between the head and the diskette Good compliance is assured when the head load pad presses the diskette uniformly against the head Compliance should be checked whenever a Data errors are encountered b It is suspected that the load pad may have become worn or contaminated with oxide or dirt 4 7 1 Procedure a Apply power to the drive b Apply a low signal to the MTRN interface line Jl pin 16 c Insert a work diskette in the drive and load it d Apply interface signals that cause the drive to be selected and an all ones pattern to be written on Track 76 of a 100TPI MOD IT drive or Track 35 of a 48TPI MOD II drive 4 6 1020914 102901A e Apply interface signals that cause the drive to be selected and positioned at the track indicated in step d f Connect the oscilloscope to Single A TP3 and TP2 GND Single B TP5 and TP6 GND Monitor the signal amplitude while increasing the force on the head load arm Note that the application of too much force will cause the diskette to slow down g The maximum increase in signal amplitude should be 15 If it more than 15 replace the head load pad see paragraph 6 5 4 8

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