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laboratory data products VR14 CRT display user`s manual

1. 27 REF Bg 6 Er 4o P SECTION B B 6 59 57 u 30 Bes 10 44 REF f 1 E BACK OF PANEL NO LOCK WASHER ONLOWER SCREWS 42 15 TE NOT SCALE DRAWING DATE EQUIPMENT UNLESS OTHERWISE SPECIFIED 12520 DIMENSION IN INCHES D DA bs HEN 9 REF TOLERANCES p oremus moe Z7 Gets 14 FIRST USED ON OPTION MODEL VRI4 FINAL SURFACE QUALITY rus DATE REMOVE BURRS AND BREAK N BA DATE 70 0 DISPLAY ASSY EE 94 VRI4 00021 CIR 5 42 x NEXT HISHER ASSY gt A ML VRI4 Q CODE NUMBER b FINISH a DUA VR14 0 H sue or 4 21 L CHK VIL e uw REVISIONS CHANGE NO 00015 Z Lean 7 2 2 VTRIa OOOIS 2 gt 2 0 2 1 5 7 7 Or 4 9 gt This drawing an
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3. T EPO A TITLE ENG PEE 70 WING o PROJ ENG E 5 A FISHMAN E o PROD 5 R NDEX ST NEXT HIGHER 55 D UA VR 4 2 REV Y zu DD VRI4 0 2 d 5 MEE OPEM 2 DIST ume E 7 6 5 4 3 E 5 35 0 _________ 89 z _____ JS 69 HOD _ IL IL TL 1 L L LLLI gt Tome Sede H D gt TTA 1 ls pid gt 2 lt aeo gt Q 2 x ipu tt dodi T P ro is 9 gt a H 2 7 On x lt 4 tru E o MA 7 u c e P m E 4 8 Qf H 5 Q Ol o e ril 4 Pj 3 oi DA 8 LEVEL INTENSITY LIGHT PEN MODULE UTILIZATION LIST O lt O G838 W684 N A225 DWG PART NO MADE BY D K Crabbe DATE ITEM NO DEC FORM 16 1031 5 37 This drawing and specifications herein the erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items with
4. 2 ISSUED 5 gt 1 T O O 7007084 3 PART DESCRIPTION 9007112 FASTON TAB 60145 1 7007084 4 7007084 5 7007084 6 E M 7 i D FASTON TAB 41287 1 AMP JUMPERS 541 CINCH JONES DIODE PACK DM15 SOLARTRON PIGGYBACK FASTONS 3000 21 ARKLESS NO gt d m 1209351266 SOCKET HSG MALE 1480273 1 MATE N LO SOCKET HSG MALE 1480274 1 MATE N LO CONTACT PIN MALE MATE N LOK 14 TEF STRD INS WIRE GRN 14 STRD INS WIRE 9107440 03 14GA STRD INS BLK ORN 14GA STRD INS BLK GRN STRD INS WIRE RED 18 TEF STRD INS WIRE WHT 418GA TEF STRD INS WIRE BLK 29 30 N g 5 9 9006864 SPACER AL 6 32 AF x 14 39 9006560 NUT KEPS 46 32 9006021 9006025 1 SCR PHL PAN HD 6 32 x 5 8 SST 9007919 FASTON TAP AMP 9006633 LOCK WASHER 6 INT TOOTH gt AT A c O Q NO TMT O OB o INIA o PSl TT d ds J 44 9006070 1 SCR PHL 10 32 x 5 16 SST TITLE ASSY NUMBER EV NO POWER SUPPLY ASSY VR14 D AD 7007084 0 0 PL 7007084 0 0 F SHEET 2 OF 3 oist je ft tT DEC FORM 16 1031 DRA 110 5 75 1111
5. O H 13 216 76 16 isa RES 120 24 10 RES 10 57 madaria lz aala ASSY r m O U o VR ll POWER SUPPLY AND REGULATOR BOARD SHEET 1 Or 3 NUMBER REV lt lt DEC FORM 16 1031 DRA 110 25 49 MADE BY Mery Ann Gilbert 22 gt SECTION DATE July 8 1971DATE ya PROD ISSUED SECT DATE DWG NO PART NO DESCRIPTION 330 X 5 IE 2 o m 2 cU 4 4 M B 1 RES 3 1300271 RES 220 5 4 1300365 RES 1K 54 5 1300369 RES 10 0 00000 1300191 15K w Se RES E o f MAYNARD MASSACHUSETTS PARTS LIST p auus EIN 1300417 2 2K id A 1 4 2 1301890 560 kw 5 N IV IN q SERERE d a RU atate qul ia e ea R1 _ 12 26 12 S 1302385 RES 750 lw 5 1303000 470 SS 1302612 4 1304870 RES 6 8 1 8W 14 M RES 500K lw 104 1310382 22 71 RES Pos 150172 21290 7 mn ns Be 1501
6. ojojololo IO O nr PY O t t t TITLE ASSY NO CODE NUMBER EFLECT A DEFLECTION HEAT SINK ASSY ee om a PL 7007082 0 0 SHEET 1 OF 1 pisT DEC FORM 16 1031 DRA 110 SUPPLY SOCKET HOUSING laSW 5 DEC 1209351 15 244399 5302 R25 tasw 5 BLU DEP X DEFLECTION CIRCUIT C BLU GY 2N4 2399 e X 2 SW 5 TOOITOSSSOS Y DEFLECTION CIRCUIT P 5 uu EE EP a NONE A 02 Q3 TRANSITOR DEC 5302 1510196 Pps I5 CIRCUIT 1209351 15 Ql 04 TRANSISTOR 2 4 399 1510362 RI R4 RESISTOR In 5W 57 1305872 FIRST USED ON OPTION MODEL UNLESS OTHERWISE SPECIEED EQUIPMENT VRIA UNLESS OTHERWISE SPECIFIED d CORPORATION uw 5 DIMENSION IN INCHES Sa a MAYNARD MASSACHUSETTS S 2 DECIMALS FRACTIONS ANGLES mm e 005 M 0 30 5 z 2 4 FINAL SURFACE QUALITY V CIRCUL SCHEMATIC REMOVE BURRS BREAK SHARP LL TEE gt ISTINIT T lt lt I CONVERSION CHART MATERIAL gt 7007082 0 0 SOMBER REV L DEC 3790 2 5790 tet Saat h
7. 14 DISPLAY 55 D UA VR14 f f L 14 8 95021 0 16 1031 110 SHEET 1 4 5 15 QUANTITY ZVARIATION DIGITALEQUIPMENT CORPORATION MAYNA H S RD MASSAC n A i 14 VRl4 D VRl4 E VRlI4 LC VRl4 LD C VR14 B VRl4 f d D 7404881 0 0 rax SCREEN 2222 2 121212 1 2 2 aM Susan coves Rt TT ame nm p re TOOTH 70232 yy n xse lt P Pc gt n sm SS EA __ 4 gt yw ne eee ee ee _ gt H N lt gt M a 42 1 t 4 11111 0 1209576 2 1009434 3610267 9006584 w c P lo N 9008202 CLIP FAN TINNERMAN 9006022 1 SCR PANHD PHL 46 32 X 3 8 SST 9006024 2 SCR FLAT HD PHL 46 32 x 5 SST 9006071 3 SCR PHL TRUSS HD 10 32 X 3 8 SST 1 T 9006071 2 SCR PHL FLAT HD 10 32 X 3 8 SST 9006024 1 SCR PAN HD PHL 46 32 X 5 SST 9006633 WASHER LOCK INT TOOTH 6 9006560 NUT KEPS 46 32 SCR PHL TRUSS HD 10 32 X 5 16 SST 9006070 1 9006635 WASHER LOCK INT TOOTH 410 SCR PHL PAN HD 6 32 X 1 SST 9006020 1 3 N gt In I in D a fo di d b E Bom PR PR o c N O
8. erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without written permission TOP MTG ASSY 0 0 7007077 PANEL CONTROL C 1A 7408425 0 9 VRI4 DISPLAY ASSY 115 VAC D UA VR14 9 9 VR14 A DISPLAY ASSY 230 VAC D UA VR14 A 9 VR14 B DISPLAY ASSY 100 VAC D UA VR14 B VR14 C 1 ASSY SUPER CON V FR D UA VR14 C 9 VR14 D DISPLAY ASSY 230 VAC SUFER COVER Tr E DISPLAY ASSY 100 VAC SUPER COVER D UA VRI4 E VRI4 LC DISPLAY ASSY 115 VAC MODIFIED FOR 6740 D UA VR14 LC B VRT4 LD DISPLAYASSY 23 0 VAC MODIFIED FOR 6740 D UA VR14 LD HIGH VOLTAGE ASSY D AD 7007079 8 8 wji gt ue 51423 e Ep G jc RS Pg ep Ms gu S Na lt gt t ji sg X 21210 s NI C OG s ele HO 2 yay lt NNI JiS m Yi MER el 7e G7 gt 5 Ly Ll 1 qo DEC FORM 119 8 POWER REG ASSY VR14 D AD 7007165 8 9 G836 5 REG ASSY D UA G836 0 8 5 HEAT SINK ASSY D AD 7007080 0 SUPPLY ASSY 0 40 707084 0 0 WIRED ASSY D AD 7007078 9 8 REGULAR H S ASSY D AD 7007081 8 2 C R
9. TITLE TASSY NO CODE NUMBER RFV ECO NO VR14 DISPLAY ASSY m D UA VR14 f f PL VR14 f f mE H 4 DEC FORM 16 1031 110 2 4 DIST QUANTITY VARIATION 1066 31 31 29 1 34 23 DIGITAL EQUIPMENT CORPORATION ARD MASSACHUSETT PARTS LIST MADE BY D CRABBE CHECKED D CRABBE SECTION DATE 12 2 70 DATE 12 8 70 1 PETERSON ISSUED SECT 12 8 70 12 8 70 1 DWG PART NO DESCRIPTION 45 9006021 1 SCR PHL PAN HD 46 32 X 5 16 SST 9006563 NUT KEPS 48 32 7 9007651 WASHER LOCK EXT TOOTH 10 Wc n 52554 VRl4 C VRl4 D VRl4 E VR14 LC VRl4 LD m 14 0 2 AM 9006025 2 SCR PHL FLAT HD 46 32 X 5 8 SST 9000120 scm SELF TAPPING 88 32 X 3 8 SST Ul O O O N dis ls is Jala 2 gt gt aq om opm T TT TITLE ASSY NO SIZE C EV 14 DISPLAY ASSY D UA VR14 g g A L 14 0 H SHEET 3 or 4 T DEC FORM DEC 16 325 1031 N870 DRA 110 elei wa 9006660 WASHER FLAT 375 OD X 187 X 036 a NO 4 Pope
10. SEW SY AIOE E i 25 ZI d t SES MATERIAL Z S Nake RI 5 NEXT HIGHER ASSY P ESSE MTS E E 51 Lx 7 D UA VRI4 CODE NUMBER REV RO TAR FINISH sae none DIAD 007084 O O SI BS R IN LS a CEST T DEC FORM NO DRD 100 2 69 4 O OO 8 MN 6 5 bo 4 3 5 9 28010046452 This drawing and specifications herein are the prop erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without HARNESS TABLE TYPE ITEM oB COLOR HEENPY ES LOCATION RED E FAN 22 27 60 WHT 4 FAN2 2 22 27 oT plesu 6 C2 NEG 22 24 CRN 7 C2 NEG peck GND I_ D De 7 WHT 10 X it CI POS je 18 GRN 2 E DO RED 2 T RED 19 bob T4 T2 1219 PL2 T 20 HO 7O Tarso EE BY C ECT NUNT oe 310 FO O 3 20 2 4 40 4 ehi E Oli HO OP See 20 GND 2 ON HV ASSY Jf J8 elo 1240 016 32 FAN EN Iz NE PTR POT 2 USE D
11. D AD 7007080 0 0 T RE E E D AD 7007082 0 0 A PL 7007082 0 0 D AD 7007084 0 0 OWER SUPPLY ASSY 1 7007084 0 0 SUPPLY ASSY TITLE SIZE CODE NUMBER ta asin SHET 2 2 IML 14 0 DRA 132 DEC 16 325 1048 1 N471 DEFLECTION HEAT SINK ASSY DEFLECTION HEAT SINK ASSY PL obl PR Let PL rg T q REV OF TITLE OPTION x LET SHEETS NO xl Lpn nrvRi4 0 2 2 DRAWING INDEX LIST eee ee xi p cs cs36 0o 1 _____ 1 POWER SUPPLY amp REGULATOR SCHEMATIC xl c cs 7007080 0 1 __ a 1 POWER SUPPLY HEAT SINK SCHEMATIC ss Lx c cs 7007082 0 1 1 DEFLECTION HEAT SINK SCHEMATIC x 7007084 0 1 p 2 POWER SUPPLY SCHEMATIC eee NM xl c mw vr14 0 3_ 2 MopurE k D IC VR14 0 1 3 VR14 BLOCK SCHEMATIC MEE ME l il lil NM MUS u l il ee NEU x 0 DISPLAY ASSEMBLY PL X 7007078 0 0 i WIRED ASSEMBLY _______ _________ o ix A PL 7007078 0 O 1 WIRED ASSEMBLY BN j NEN b d e l 4 ENGINEERING SP
12. Heti lo fo mamma gt Et EI 2 Ov o ui oi fo loi z o 2 c 5 5 19 _ T gt ____ t arsma _ gt iio Gite N gt ima 14 LLLLELELLLLEELLELLI L E ama 3I 7 7 LLLLLLLLLLLLLLIES gt _ 5 gt m LEER a Q T z E ae gt 2 e LEM z S 5 Z iol X Os Ov 9 joa Z lt molwoll 9 Lol el lt gt p ju ccu G 2 a Kf lt 91 O H 3H 9 7 lt 2N 3 E ul ii mi 3 4 8 Z yu DS am O neu S Bl Coe c lt H lt I5 a r 8 gt Of SI O E lt 7 U I O gt gt E A E m m lt Hi S Leelee 9 att lt Oo Of mi NT Z I ol ol o gt Ac gt e a OY AI aD a o ul gt 0
13. Q gt qu J6 INK 7 Mas T 2 10 n ASSY y ER Y INPUT i Br P2 9 Sl ome a a Y INPUT 2 8 X GND ae 1455 X INPUT gt xl 5 V IN ll o X INPUT Mo LIGHT PEN H 219 SIG 5 2 i KB SIG 2 INPUT T REMOTE 5 INT 1 2 25 SPEAKER 15 SH ap INT 2 INT 2 DIRECT POWERS T _ YEL YEL BLK i 5 gt SOCKET gt GRID TO 80V 4 LQ 52 n lt a x z AMPHENOL 14 PIN v 3 oj 10 aae a PP YEL GRY A3R A3S a x 2 J B t ik gt gt 2 SELECT 66V_ CATHODE Q z z 0 22 498 222 x INT I BLK Ix BRN GRY O o ovo 5 lt GRY C GN D a gt gt gt GRN 6 16 OO gt gt WHT Saget P aN 2 DIRECT Nn AM z koc d ORN GRY D t 89 POWER SUPPLY m V RI4 T FRONT PANEL O LIGHT PEN OPTION SCENE 7 210 1 4W 5 BRIGHTNESS 8 LEVEL INTENSITY OPTION YEL z IRSTUSEO OPTION MODEL UNLESS OTHERWISE SPECIFI
14. A FISHMAN CHK LEY EZA DEC FORM NO DRD 100 Qo 4 3 2110 0 8202004 2 WIRE TABLE NOTES No DRE TWIST 2 WIRES B TWIST PER INCH NAME COLOR FROM MIN amp 4 TWST PER INCH MAX 2 2 USE TERMIPOINT CONNECTORS 1077246 8 32 i hikas 1 aaa 1 1 S I ewj s24v 6 1 Ader rt agar Aone 5 11 mL _ Z INT 19 22 WHT A49 7 Re peenaa 35 2 22 75 14 2 gt Jguysev A 2M 55 4 psie zo 5c feo Bw 15 lt eo sco jeder 5 11 voke iS sev 75 5 Asse xvowewerpne S Yexe wer z Apan WAT 3e 2 vvo WaT RES 1 oc 7 Rep BOW _ 56 zo Eco Ade m ewe lt ewe fet f pes al s Eck jvez a sv SEE NOTE aoe _ 5 EAweue ee war
15. 160 5 MALE AMPH 1201251 160 4 J l E E e 5 1 Omi b OS OS mo sN N jo o IO 1 2 TERMINAL 2101 06 00 SHAKE PROOF FOAM 5 x 3 4 STICKY BACK 3M TIE WRAP SST 1 B D 006776 9006780 9006904 O O O N O O O O J oO W 1 N O Ol NO ERE U U 720781 1 P I a i WEN E 707081 2 N a KOKO o s le b 5 7007084 3 y 2 9007917 TITLE FASTON TAB 50902 ASSY NO POWER SUPPLY ASSY VR14 0 0 7007084 0 0 ISHEET 1 3 NUMBER 7007084 0 0 gt 5 DEC FORM 16 1031 DRA 110 DIGITAL EQUIPMENT CORPORATION D MASSACHUSETTS PARTS LIST MADE BY D Crabbe CHECKED p crabbe DATE 10 9 70 DATE 10 22 70 1 a U 1212 12121
16. DRD 100 This drawing and specifications herein are the prop of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without written permission ITEN sss SERS S II AARRE 7 6 VEE DESCEIPTION Fon ANG ace levee ser je ida _ pee CO ea L z __ ace j bee B pee x k Lre jee 642 e eoo X 2 3 7 5 pee sre 222 131 7 3 Tae L Lre exw2c lw L pes pey pex __ __ ew enc L Par Is __ 77778 P 22 222 SELECT jzzeerewpe _ DES GNATION INDICATES WIRES 70 SocOreco N O X ENC 72 BNC 4 507 4 ecc o C GND POINT 7 POLREITY g ENC BOT 7 2 3 Z 5 7 8 10 12 O O O 13 74 15 06 77 78 49 20 22 2 24 O O FIM PHENOL Z Z IN
17. m O onic lt j DEC FORM 16 1031 110 5 53 THIS SCHEMATIC IS FURNISHED ONLY FOR TEST AND MAINTENANCE PURPOSES THE CIRCUITS ARE PROPRIETARY IN NATURE AND SHOULD BE TREATED ACCORDINGLY COPYRIGHT 1970 BY OIGITAL EQUIPMENT CORPORATION DEC FORM NO UNLESS OTHERWISE INDICATED RESISTORS 1 4 5 DIODES ARE IN752A 5 6V CAPACITORS ARE 5 El E2 ARE 9 gt EYELETS AL2 SENSE RAW 20V RI5 013 014 Hera IN4OO IN400 AR2 NPN BASE AH2 NPN COLLECTOR 20 852 4 IOUF AD2 450V AJ2 2 GND SENSE GND 02 AS2 RAW 20V DIS DI6 IN400I IN4OO BK2 4 SENSE BE2 PNP BASE U 2W PNP COLLECTOR DEC2219 4 20V REG C7 270 10 BL2 GND SENSE 315881515 X BE 2 SE DIO 4004 09 IN4004 510 1 0 9289 4214 BR2 BN2 2 AF2 FOCUS 80V BRIGHTNESS R35 500K iw 10 R36 R37 2W 120 10 pi 2W R38 IN4004 4004 096 IOOK _cI5 Cie 3 4W 25UF 10 450 76 25UF 25UF ISOV I50V I50V y Moore TRANSISTOR amp CONVERSIOR CONVERSION CHART __ CHART JY 7 ee SS SI Mems 122 peceso4 bo ERN wi290 J
18. r 1 oT 45 SECTION D D gt u FIRST USED OPTION MODEL DESCRIPTION PART NO V R 4 PARTS LIST UNLESS OTHERWISE SPECIFIED EQUIPMENT DIMENSION IN INCHES 0 7 CORPORATION DECIMALS ANGLES 2 Ello PR J NG DATE S MAYNARD MASSACHUSETTS TITLE VRIA 2 2 22 DISPLAY ASSY REMOVE BURRS BREAK SHARP PROD gt CORNERS SURFACE QUALITY a4 MATERIAL NEXT HIGHER ASSY lu eo TTT 4 or 4 Jes _ DL 100 8 7 6 5 4 3 2 zat 5 13 gt SIZE CODE VR14 f VR14 A VR14 C VR1L4 D 14 14 VR14 LD VR14 B ag DIGITAL EQUIPMENT CORPORATION QUANTITY VARIATION PARTS E 5 1 DATE 2 8 1 D AD 7007077 0 0 mre EX EE HIGH VOLTAGE ASSY POWER REGULATOR ASSY VR14 DEFLECTION HEAT SINK ASSY AC DATE 7 DWG NO PART NO DESCRIPTION POWER 0 0 7007082 0 0 __ D AD 7007084 1 0 RM 1 SLIDE 16 TRAVEL CHASSIS TRACK 21 JPPLY 553 m POPPA o Is o lo wv 1 N Je O a E 2 a IN TITLE ASSY NO CODE NUMBER REV
19. 21229 T SEESESSSSESES __________________ CU CORPORATION MAYNARO MASSACHUSETTS CODE POWER SUPPLY AND REGULATOR BD Tw 5 55 ul e 2 gt z 6836 0 I 10 O 9802002 aya 2 ROT SCALE DRAWING DATES 8 7 5 4 3 EU an at not e WIRE TAE CONNECTION 4 7 7 5 zz lea 74 22 2 2 a Bety 7 2 2 __ 4 2 f GEN n Priz 5 O 8 114 LT e 7 2 3 3 4 5 6 L zi 2 LI Lae S 9 2 Z ez FIRST USED ON OPTION MODEL i VR4 V MEAM moe T TOLERANCES DECIMALS FRACTIONS ANGLES 5 005 1 64 0730 o FINAL SURFACE QUALITY REMOVE BURRS AND BREAK SHARP JE MATERIAL m x FINISH 8 7 6 5 4 3 NOTES USE TIE HORS NECESE PEK gt EQUIPMENT RD E me 28722 UM PS HEAT SINK L 76 ASS Y NEXT HIGHER ASSY VR 4 2 Z2 V CODE NUMBER 7007080 0 0 per 2 1 5 57 REV SIZE 5 0 7007080 0 0 UJ DIGITAL EQUIPMENT CORPORATION QUANTITY VARIATION MAYNARD S MASSACHUSETT PARTS LIST MADE BY 1 Devin CHECKED D Crabbe SECTION DATE 0 14 10 DATE 10 15 70 1 ja 4 ISS
20. 22 43 Orange 42 Gray Yellow 22 43 Green 42 Gray Blue 22 Vdc Blue X Current Sample Y Current Sample X Input Signal Y Input Signal Regulated dc Regulated dc For W682 1 2 Filament 1 2 Filament G2 Brightness G1 Focus Cathode With Negative Pulses PNP Base 2N4399 PNP Emitter 2N4399 All Collectors NPN Base 2N5302 NPN Emitter 2N5302 Emitters of 2N4399 Bases of 2N4399 Collectors of 2N4399 Emitters of 2N5302 Bases of 2N5302 Collectors of 2N5302 All voltages measured with respect to ground chassis or BOIM Indicates voltage depends upon input signal Figure 4 1 Voltage Chart Continued on next page 7007165 0836 Regulator Circuit Connectors P2 P4 Pl 1 P1 3 6 PI 4 2 1 P2 2 4 7 9 P2 3 P2 5 P2 6 P4 1 P4 2 14 P4 3 P4 4 5 4 6 P4 7 8 P4 9 P4 10 4 11 P4 12 P4 13 P4 15 4 2 1 Picture 43 Vdc Ground 43 3 5 Vrms Ground 3 5 Vrms 70 Vrms 200 P P 150 Vrms 400 22 Vdc Red Ground Black 22 Vdc Red 0 Black 80 to 400 Red 400 Orarige 3 5 Vrms Brown 3 5 Vrms Brown 80 Vdc Gray Green 0 to 40 Violet 80 Gray Orange 22 Blue 0 Black 22 Blue Figure 4 1 Cont Voltage Chart Raw dc Raw dc 1 2 Filament 1
21. AL2 RAW 22V AR2 2N5302 BR2 BN2 FOCUS 80V 7097080 C1 22 REG 2704F 0 235 10 500K R36 C14 IN4004 10 10 DS IN4004 AD2 450V 2 2 CAS GND SENSE Ss d ou m R16 IN4004 150V 4K GND BD2 BS2 RA RAW 22V D15 016 44001 IN4001 T BK2 oW E SENSE 1 8W 2 1 R17 1 78K 1 8W 1 C7 27 15V 10 02 IN752A BL2 GND SENSE 22V REG 7007080 AE2 BP2 80VAC 80V R37 420 2W 011 012 10 1 4004 IN4004 C18 25 150 AF2 BRIGHTNESS R38 100K 34W 10 76PR C19 25 150V 42 0317 Figure 3 2 C836 Circuit Board Part of The 7007165 Power Regulator Assembly 3 9 is made with the 12 passing through and establishing 6 2V across across reduces the dynamic resistance of the reference by removing high frequency fluctuations The 5 V reference voltage is delivered to R2 which ties to the summing point pin 2 of operational amplifier The feedback from the output regulated voltage through R3 is also applied to the summing point of The nature of the circuit is that a null will be maintained at pin 2 of Therefore because the voltage on R2 reference is stable the only variable is the output Whenever the output changes for any reason the null is disturbed at pin 2 of then forces the output to change in a manner that return
22. 1 4 gt gt gt w 3 FOR VR2 OPERATION DELETE Ti 4 ADD TO DELETE T2 3 ADD TO T2 earn 20 72 15 D o z TR 2 BLU 5 7 19 121 2 4 2 J m ORN 43 4 ORN 43V BLK Tos STRIP inert woe D Cake PWR PARTS LST amp 5008638 900726 2007222 6101600 N LOCK 3 209 55 MATE N LOCK 6 ____ 24635 6 RECEP AC MALE 160 5 AMPH 5 VJ 1201252 AC FEM 16 4 AMPH II amp M 1201251 SISWITCH POT 100 Vow 1310383 LIGHT 15 1209348 RECTIFIER DM 15 DM 15 1105799 9006904 2 ICS7007084 O 1 D SRI 99 pam LIED LS f re EQUIPMENT 2 CORPORATION Dm MAMANG 727 HIGHER ASSY D AD 7007084 O O _ 0 517007084 0 0 De 2 5 79 Tico 2 51 72 GND 2 3 FOR 2 OPERATION DELETE 4 ADD TO TI 1 DELETE T2 3 ADD TO T2 1 J TO ANODE HV SW
23. 9107410 86 18 STRD TRACER GRY BLU 24 9107360 00 18 STRD BLACK 28 9107350 22 22 AWG STRD TEF WIRE 9107350 99 22 AWG STRD TEF WIRE WHITE 9107256 1 422 TEF TUBING BLACK 31 1209350 15 CONN PIN HOUSTNG MATE N LOK 2 1010195 0 9007230 9107420 09 9107410 85 TERMI POINT CONNECTORS 22 AWG STRD TEF TRACER BLK WHT 18 AWG STRD TEF TRACER GRY GRN OQ Q Qs lt lt 4 5 C2 PP lol e E mr j m ASSY NO WIRED ASSEMBLY VR14 D AD 7007078 0 0 2 lt m O O 2 O E NUMBER 7007078 0 0 gt O O 5 SHEET 2 OF DEC FORM NO 16 1031 DRA 110 N 5 45 l 6 3 225 This drawing and specifications herein are the prop erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without written permission 5 25 REF 35 37 19 13 25 FIRST USED OPTION MODEL DESCRIPTION PART NO VRI4 Po PARTS LIST UNLESS OTHERWISE SPECIFIED DRN DATE DIMENSION IN INCHES HOV EY 10 2 6170 Tick TOLERANCES CHK D DAT MAYNARD MASSACHUSETTS D CRABBE 4 2 70 ENG TITLE c RABBE G8
24. it will break off 4 12 4 3 5 High Supply Removal To remove the high voltage supply proceed as follows Step 1 Remove yoke and CRT as outlined in Paragraph 4 3 4 Ensure that the line cord is unplugged Disconnect the two red and two white wires from the high voltage supply from and TB2 of the right side chassis Remove the cast bezel by removing the three right and left retain ing screws Remove the two side and two bottom high voltage assembly mount ing bracket screws and remove the high voltage assembly out toward the front of the unit 4 13 CHAPTER 5 ENGINEERING DRAWINGS The drawings in this chapter are current at the printing date of this manual If any discrepancies exist between these drawings and those delivered with the unit the set of drawings shipped with the unit are to be considered the most accurate Drawing No A ML VR14 0 D UA VR14 0 0 A PL VR14 0 0 D AD 7007077 0 0 D IC VR14 0 1 D DI VR14 0 2 A PL VR14 0 3 C MU VR14 0 3 D AD 7007078 0 0 A PL 7007078 0 0 D UA G836 0 0 A PL G836 0 0 D CS G836 0 1 0 0 7007080 0 0 A PL 7007080 0 0 5 7007080 0 1 0 0 7007082 0 0 A PL 7007082 0 0 5 7007082 0 1 0 0 7007084 0 0 A PL 7007084 0 0 0 5 7007084 0 1 Table 5 1 Engineering Drawings Title Master List VR14 0 VR14 Display Assy VR14 Display Assy Top Mtg Assy VR14 Block Schematic 14 Drawing Index List Mod
25. 144 BLOCK 1202188 VOLTAGE CHAIN 55 5308753 0 2 LOGIC FRAME DECALS A 88 5308753 0 4 LOGIC FRAME DECALS z o m P 4 gt m ex RESISTOR 100 1 4 5 RESISTOR 0 54 20W 196 CONTACT TERM PIN SOCKET AMP INC SCR PHL HD PAN 44 40 x 3 8 SST NUT KEPS 44 40 SCR PHL HD PAN 6 32 x 5 16 SST 9006021 1 NUT KEPS 46 32 18 AWG SOLID BUSSING POZIDRIVE SCR FIL HD 8 32 x 5 8 SST 18 AWG STRD TEFLON RED 18 AWG STRD TEFLON WHITE 9107360 88 18 STRD TEFLON GRAY 9107360 66 18 STRD TEFLON BLUE S Siepie ______ gt fs lalala S e NININ 5 jejejejeje y 1 9107360 77 18 AWG STRD TEFLON 4 2 9107410 84 18 AWG STRD TRACER GRAY YELLOW __ TITLE ASSY NO A CODE NUMBER ECO LE v amp lt WIRED ASSEMBLY 14 0 0 7007078 0 0 L 7007078 0 0 looo SHEET 2 121 T TII fF T DEC FORM 16 1031 110 5 43 DIGITAL EQUIPMEN MAYN MASSAC MADE BY cahill CHECKED DATE 1 70 Al ENG 5 6 PROD Fe ISSUED SECT DATE DATE 6 70 1 TEM DWG PART DESCRIPTION 79 QUANTITY VARIATION gt I lt lt N a
26. HV PTI PT3 SOLDERED PER TABLE ABOVE WIRE TABLE 9 JUMPER TABLE o A M Tice Teon G O i DEN 2 lt 2 2 DESCRIPTION FIRST USED MODEL _ DO NOT SCALE DRAWING SCALE DRAWING 0 EQUIPMENT VRIA UNLESS OTHERWISE SPECIFIED 172 RN EC 0 12 70 t CORPORATION DIMENSION IN INCHES Le DATE MAYNARD MASSACHUSETTS A TOLERANCES POWER SUPPLY gt 2 ANGLES DATE PC 2 2 2 005 SA 0730 Igls FINAL SURFACE QUALITY PRO E Ky REMOVE BURRS BREAK SHARP ASSY V RI4 X MATERIAL lZ NEXT 6 ASSY s FINISH DAD7007084 0 Or NOD 7 sue 2 or 2 __ TT TT TT DRD 100 8 E 7 6 5 3 2 1 5 71 QUANTITY VARIATION DIGITALEQUIPMENT CORPORATION MAYNAR HUSETTS D MASSAC MADE BY D Crabbe ICHECKED D Crabbe SECTION DATE 10 9 70 DATE 10 22 70 1 DATE 2720 DATE 1 TEM DWG PART DESCRIPTION NO E IA 7408402 0 0 PLATE SIDE MTG B MD 7408416 0 0 COVER PROTECTION 0 1 7408433 0 0 COVER CAPACITOR HOLDDOWN 1A 7007147 0 0 D SC 7007084 0 1 0 7408407 0 0
27. JA IA 29 ww SEE 27 lt eee fer aea sess 27 xnes AB2 27 Br rim cc YK E U GEI 2 ___ 24 BLK GND 24 e BLK JAozv ________ 29 22 WHT war Ino asig 80V 351 18 eRYVGRNA 25 ABIL __ 22 cwm ITEM Tee D S FIRST USED OPTION MODEL DO SCALE DRAWING 27272 QA EQUIPMENT menan ne DF Du Cathe WIRED ASSY NEXT Henan L ASSY 222 NUMBER EL DIAD 7007078 0 0 e FINISH E um sr 7 oy fost 11 111 3 2 n 1 5 41 c 2 o x DECIMALS o FINAL SURFACE QUALITY REMOVE BURRS AND BREAK SHARP RNERS DIGITAL EQUIPMENT CORPORATION QUANTITY VARIATION MAYNA H E S RD MASSAC MADE BY J Cahill CHECKED p crabbe DATE 10 2 70 DATE 10 2 70 1 D E e PROD R RA ISSUED SECT E 7O 20 1 x DWG PART DESCRIPTION D IA 7408422 0 0 FRAME LOGIC 0 7407114 0 0 BAR 1209340 00 8 CIRCUIT MATE N LOK SOCKET AMP 1202244
28. SPACER MTG BRKT MTG SPACER POWER SUPPLY HEAT SINK REGULATOR HEAT SINK ASSY REGULATOR H S ASSY P L DEFLECTION HEAT SINK ASSY DEFLECTION H S 55 DEFLECTION POWER AMP ASSY DEFLECTION POWER AMP PL POWER SUPPLY ASSY POWER SUPPLY ASSY PL POWER SUP CABLE HAPN COVER CAPACITOR HOLD DOWN PLATE SIDE MTG COVER PROTECTION C 1209229 D 7408434 C 1209228 0 7406837 1210113 7408408 1211106 1409964 7408403 1007006 AD 7007077 bi 1007077 1408401 D 7408407 7408425 1408425 0 14 7007088 D AD 7007079 A PL 7007079 0 14 7408420 B MD 7408424 B MD 7408413 D SC 1210169 D AD 7007165 PL 7007165 7408439 MD 7408436 M UA 6836 9 0 PL 6836 0 9 AD 7007080 PL 7007080 C MD 7408438 C MD 7408437 D SC 1210131 0 D D A D 7007081 L 7007081 D 1007082 L 7007082 D 700708 L 1007083 DESCRIPTION PART NO 5 gt gt 2 gt gt gt gt gt F C M ELEC DI DEPT USAGE FIND NO DESCRIPTION VR14 DISPLAY 115 VAC 14 DISPLAY 230 VAC VRI4 B DISPLAY 100 VAC VRI4 C DISPLAY 115 S VRI4 D DISPLAY 230 VAC S VRI4 E DISPLAY 100 VAC 5 VR14 LC DISPLAY ASSY 115 VAC VR14 LD DISPLAY ASSY 230 GT 40 CIRCUIT SCHEMATIC VR14 MODULE UTILIZATION MODULE UTILIZATION PL ENGINEERING SPECIFICATION CHECK OUT AND ACCEPTANCE PROCED
29. a 300 ns intensify pulse The driver must sink 4 mA when low NOTE The intensify signal must be delayed from the X and Y position signal for an appropriate length of time to allow the deflection coil to settle the electron beam to its re quired position Failure to do so displays smeared dots that are located incorrectly on the screen 2 8 Table 2 2 Control Settings Input Position Rear Deflection Setting Polarity Switch 2V to 5V With no inputs set 0 0 center position on X and Y to 2 to 5 is up center 0V at A02 A and to right for X A03 A for Y to 2 to 5V With no inputs set 0 0 upper right 2 2 A02 A screen with X and Y position potentiometers OV to 2V to 5V With no inputs set 0 0 lower left 2 2 dc 02 03 with X and Y position potentiometers NOTE All signals are BNC with respect to BNC Reversing in put connections is the same as reversing the rear polarity switches All single ended signals applied to must have BNC tied to signal source ground The BNC can not be left open circuited Also at least a 500 ns waiting period must be allowed to intensify a dot before commanding the electron beam to move to its next location Not giving enough time to intensify a dot after the de flection is settled will also smear the dot since the deflection amplifier will start dragging the dot to the new position The amount of delay requi
30. and shut down power If the 20 Vdc is above 22 Vdc refer to Appendix A the 20V regulator has a fault If OV or below 20 Vdc the 20V is overloaded continue to next step With a oscilloscope or meter measure 2 2V maximum at 02 with respect to ground BO1 M This point A02 A is the X axis deflection coil current sample Because coil current flows through a 0 5 ohm resistor voltage measured at A02 A multiplied by two equals the current flowing With the A225 circuit cards removed no coil current should flow Momen tarily turn on power to the VR14 If A02 A has any voltage plus or minus refer to Appendix B a deflection power transistor is shorted Measure the same as in Step 5 for the Y axis deflection coil current at 03 with respect to ground 01 Again momentarily turn VR14 power on and off voltage should be read this indicates no Y deflection coil current is flowing If any voltage is observed refer to Appendix B since a Y axis deflection transistor is shorted probably Replace the 5838 circuit into AO and the A225 circuit into A02 Still leave the Y axis A03 board out Measure less than 2 2V at pin A02 A with respect to ground 801 Momentarily apply power If the voltage is within safe limits less than 2 2V leave power on and adjust the position potentiometer on the A225 circuit Doing this should change the voltage reading on A02 A proving the A225 indeed is controlling the coil cur
31. be sidered grounded and the collector resistor R23 is not tied to 20V but for analysis tied to 40V Q2 has the capability of swinging its collector almost a full 20V This large swing is necessary for the yoke and must swing as close as possible to the 20 The reason for this will be explained later The collector of Q2 drives Q3 and Q4 which are emitter followers for the positive and negative outputs Since a low output impedance 15 necessary emitter followers are used however Q3 and Q4 are not capable of handling the output power necessary since each can only drive 0 5A bootstrap power stage is used to raise the emitter follower current capability to the 4A required This is accomplished with two power transistors on an external forced air cooled heat sink 3 5 These external transistors are essentially slaved to the Q3 and Q4 emitter followers Because positive swing and negative swing work in the same way only the positive is described When the amplifier is required to deliver positive current in the yoke the circuit responds by turning Q2 on thus placing a positive voltage on the base of Q3 Q3 s emitter responds in a similar manner however it cannot supply the necessary yoke current Still Q3 attempts to deliver the necessary current Unlike a normal emitter follower Q3 s collector is not tied to 20 but instead to the base of the 2N4399 Power Transistor Thus when Q3 tries to deliver the output c
32. is 125 Vac the high voltage is 12 5 kV Because the electron beam is accelerated by the high voltage the ability to deflect th beam will change as the high voltage changes If a constant deflection current flows through the yoke the amount of deflection is reduced if the anode high voltage is increased smaller displayed picture the deflection grows if the anode high voltage decreases larger displayed picture The actual deflection factor change is proportional to the square root of the ratio of the old anode voltage to the new anode voltage i e deflection factor For example if the high voltage is halved the de flection would grow 1 414 V 2 4 In terms of line voltage the deflection factor is approximate ly 0 4 of the change i e a 5 percent line change causes a 2 percent deflection change 3 5 INTENSITY CIRCUIT The intensification of points on the screen is controlled by the W 82 circuit board The intensity signal is routed to pin J This signal is a transition from a high to a low While the Z signal is at a high above 2 4 the output from gate A pins 8 9 10 is low When the Z input is low momentarily the output of A goes high This positive going transition is ac coupled through C2 and becomes a positive spike that exponentially decays to 0 The time constant of this decay is determined by C2 and R4 This positive going spike is the input to gate B pins 11 12 and 13 Also as input to B is the channe
33. potentiometer on the G836 which can adjust the maximum brightness range of the brightness potenti ometer The 400 is supplied directly to G and also to one side of the focus potentiometer on the G836 board The wiper of the focus potentiometer goes directly to the focus electrode on the 2 2 1 INSTALLATION 15 shipped either as a standard RETMA 19 in by 10 1 2 in 10 7 16 in rack mounted unit or as a table top model without chassis slides with its own decorator cover The 14 can operate from a power line frequency between 47 and 63 Hz The input line voltage however is specified by the letter designation after the 14 is 115V A D is 230V and is 100V The VR14 can operate with any of the three input line voltages simply by changing the jumpers and intercon nects on and 2 see Figure 2 1 Equipment cooling is the most important VR14 installation requirement Fans draw air from the bottom of the unit therefore at least 1 in of free air space must be provided below the bottom chassis The table top model keeps the bottom 1 in above the table surface with four adjustable feet In the rack mounted unit if equipment is mounted immediately below the VR14 as long as there is open area under the 14 fans a screen is acceptable a solid plate closer than is not proper cooling can occur The same requirements apply on the
34. 11 LLLI LLL 2 lt D _____ 5 E _ recor ete PTT TT 64 D 3 so 2 __ 11 TTT TT EEE ET Posy eve 11 L o n T O 7 2 Hi 2 o 9 3 15 216 o gt 0 gt o JEER i Qo x 9 1 QU H Ow oN 4 A V p lt 5 2 NI 2 wasa E Zana LL lt E x lt r4 4 m Q e lt O m gt Q 7 gt A W lt lt 2 lt a D lt m 2 g x a olo 5 9 O O lal ala NO TITLE 16 1031 110 5 77 gt NES CHANGE NO REV VRIG 00005 1 BRASS O x BRASS FI Q Q SI RED TIN 2 L4 HV P FIRED ND LUG TO CRT ANODE 14 TO H V SWITCH REG vR20 BI 2 5 z I tel RAC 2 lt lt t 8 x u
35. 2 Filament 80V tap 400V tap Regulated Hot Sense Cold Sense Focus G2 Filament Filament To Brightness Potentiometer Brightness Preset For W682 Hot Sense Cold Sense Regulated Probably the most common failure mode with this type of equipment is no picture Unfortunately this condition can be caused by almost any malfunction such as a loss of input intensity pulse incorrect input deflection signals driving the beam off the screen a power supply fuse or fan failure thermal cutout The following sequence of events leads to the isolation of the fault s Step Procedure 1 Check fuses If they are in good condition continue If not replace any that are blown and then continue If a blown fuse is replaced leave power on only long enough to complete each check in this procedure 2 Remove all input signals at the rear of the unit and all modules except W682 and G836 3 With voltmeter or oscilloscope measure the 20 20 to 22 is acceptable This can be measured between B01 V red wire and BOI M which is ground Momentarily apply and shut down power If the 20V is above 22V refer to Appendix A the regulator has a fault If OV or below 20 occurs the 20V is overloaded continue to the next step 4 3 Continued on next page Step Procedure Set up to measure 20V This can be found between B01 R blue wire and B01 M which is ground Momentarily apply
36. 25 YA VARIATION 8 R2 ARE 3 3K 1 4W 5 FOR INPUT SIGNALS LESS THAN 5V 22V YOKE ASSY 7007088 TO PIN A YOKE RETURN TO PIN H SIGNAL GND 12 0315 Figure 3 1 X and Y Deflection Circuit 3 3 Because the amplifier has voltage gain only small voltage is needed between pins 10 and 9 of E2 to cause large changes in the output Pin 9 of E2 is referenced to ground through R13 which is strictly an impedance balancing resistor that minimizes offsets in E2 due to temperature changes There fore pin 9 is essentially grounded If any voltage appears at pin 10 of E2 the output will immediately respond in a manner that tends to reduce the voltage at pin 10 to zero thus a null is always achieved at pin 10 of E2 If a variable voltage is present at the input of R4 the output or yoke current will vary in such a manner that a continuous null is achieved at pin 10 The only way this can occur is if instantaneously the yoke current undergoes exact equal and opposite changes to those occurring at the input to RA Therefore the yoke current will be an exact but opposite polarity replica of the input voltage In absolute numbers the actual yoke current versus input voltage can be determined by comparing resistor ratios For example if 1V is applied to the input of R4 1 mA will flow through R4 This occurs because the amplifier forces pin 10 of E2 to OV thus one side of R4 is OV the other is so mA fl
37. 36 POWER A A 5 0 30 A FISHMAN REGULATOR BOARD VE BURRS AND BREAK SHARP A comune sonene aunn o Peren sonli ASSEMBLY D AD 70071 65 00 SIZE CODE NUMBER REV ee REVISIONS 6 0000 FINISH sur or jos 2 1 77 100 8 7 5 4 3 5 47 DIGITAL EQU IPMENT CORPO RATION QUANTITY VARIATION SECTION ISSUED SECT DWG PART DESCRIPTION D CS G836 0 1 CIRCUIT SCHEMATIC K CO G8 36 0 4 X Y COORDINATE HOLE LOCATION AH G836 0 5 ASSY DRILLING HOLE LAYOUT 5 6836 0 6 MODULE ECO HISTORY MADE BY Mary Ann Gilber DATE July 8 1971 et So A Tem M m k To W Me 30 UJ 09221 ETCHED CIRCUIT BOARD 000023 CAP 330PF 1007 5 D M 100V 5 DL ML 000042 1000 100 5 000080 SOUP 507 10 75 S TANT 010 100V 20 DISC 27 100V 5 CAP 27092 157 10 S TANT NO 5 gt m Oo enn J 11 12 1001886 ajo o FH Ww VU vm be va Ri Fr TP o 16
38. 4 UNLESS OTHERWISE SPECIFIED 4 CORPORATION DIMENSION IN INCHES MAYNARD MASSACHUSETTS TOLERANCES 2 10 ea m PROD IS Ly Dir Me FRMETTUNS ANGLES nes 0 30 FINAL SURFACE QUALITY REMOVE BURRS AND BREAK SHARP m iv thie ninemsn REVISIONS _ FISHMAN CHANGE NO VRI4 90002 SINK ASSY 1 E MATERIAL este NEXT HIGHER ASSY 4 D UA VP 4 NUMBER SEV BB FINISH SCALE DIA 7007082 0 C E SY o 7 os T LLL I eae 7 5 4 3 2 5 63 DIGITALEQUIPMENT MAYNARD MASSACHUS PARTS LIST CHECKED D K Crabbe Oct 15 1970 P TT R QUANTITY VARIATION E MADE BY DATE October 15 1970 DATE ENG OLL on DATE 76 DWG PART W Hovey ISSUED DESCRIPTION 0 0 7007083 1 0 C MD 7408437 0 0 DEFLECTION POWER AMP ASSY BRKT MTG SPACER C MD 7408438 0 0 SPACER MTG 1209351 15 SOCKET HOUSING MATE N LOK CPS 1953 4A CLAMP NYLON I D SCR PHL PAN 6 32 x 5 16 LG WASHER FLAT 6 SST _ SCR PHL HD PAN 6 32 x LG SST WASHER INTERNAL 6 32 SST TTE WRAPS SST 1B D AD 7007083 2 O DEFLECTION POWER AMP ASSY ee LT CALL oq v m xx g gt j m c m o
39. 5 5 lt 316 7007088 LESS THAN SV SIGNAL WILL E Ma MARKED A225YA 53 jog PWR V neal L GND lt M Qr 5302 H SIGNAL GND J SW ee _________ 7007082 YOKE 2 V DC 2 0 5 RETURN 25W FROM THERMAL E SIGNAL 115 ee CUTOUTS GND 115 115 THERMAL T CUTOUT UD OMA HIGH FORMER POWER SUPPLY VOLTAGE REGULATOR BOARD POWER 6836 SUPPLY VRI4 FUNCTIONAL BLOCK DIAGRAM MAINTAINANCE DRAWING 8 LEVEL INTENSITY CONTROL OPTION SELECT BRIGHTNESS PRESET O LIGHT PEN OPTION 2 f BRIGHTNESS Z INTENSITY INTENSITY INTENSIT Y OPTION W682 BITS uu CW6 84 8QV FAULT 80 V FEEDBACK 2 PROTECTION T SR G 838 C840 _ CURRENT gt X TO X Y GAIN POSITION SAMPLE DEFLECTION S 2 DEFLECTIO OF ON INPUT AMPLIFIER K ogy Ags 2 1 QUEE C RE PARTS LIST gt UNLESS OTHERWISE SPECIFIED EQUIPMENT UNLESS OTHERWISE SPECIFIED c 125 70 DIMENSION IN INCHES MAYMARO MASSACHUSETTS UB TOLERANCES Bp PE TITLE 2 9 Y INPUT DE EST M BLOCK 5 FL ION PRO S AMPLIFIER Sunes AND SOAP SCHEMAT
40. 881 TRANSISTOR 2219 TRANSISTOR 2955 k e 2 5509718 MIA t 9006011 SCREW SLOTTED 4 x3 8 557 9006556 NUT HEX SST 2 ASSY 512 NUMBER REV ECO NO POWER SUPPLY AND REGULATOR BOARD A G836 0 0 D SHEET 2 3 usr vo v tw uw I Vo I F oO r m ______ 1 _ 26 30 19 ss 28 mE maqa asa Ww E E 8 f DEC FORM 16 1031 DRA 110 5 51 ______ _ 25 2 4 9 gt 0 NUMBER G836 0 L l l QUANTITY VARIATION ______ 1 111 Uu T O 2 2 o u ul Uu 0 gt H O lt 5 Qo c ag O ci ja gt qu ccu ue HEB Ok n ae 4 Uu a E Vu N LL lt lt E4 Hi m gt E cx ul Hio lt A aef Fay TiS 1 z lt G a z 1 a Ws sel t lt zd c 5 lt E F s gt A z Sue 9 9 N gt
41. Digital i MAVA digital VR14 display user s manual boratory data products DEC 12 HVCRT C D VR4 CRT display user s manual digital equipment corporation maynard massachusetts Ist Edition April 1971 2nd Printing Rev June 1971 3rd Printing Rev June 1972 Ath Printing Rev January 1973 5th Printing July 1973 Copyright 1971 1972 1973 Digital Equipment The material in this manual is reference only Operating characteristics and func tional descriptions are provided solely as reference information and are subject to change at any time without prior notice The drawings specifications and descrip tions herein are the property of Digital Equipment Corporation and shall not be reproduced or copied in whole or in part as the basis for the manufacture or sale of items without written permission This manual was written by the PDP 12 Engineering Department with assistance from individuals in other product groups at DEC The following are trademarks of Digital Equipment Corporation Maynard Massachusetts DEC PDP 12 FLIP CHIP 1 1 1 1 2 1 3 2 2 1 2 2 2 3 2 4 2 5 3 3 1 3 2 5 3 3 3 4 3 5 CHAPTER 4 4 1 4 2 4 2 1 4 2 2 4 3 4 3 1 4 3 2 4 3 3 4 3 4 4 3 5 CONTENTS GENERAL INFORMATION General Description Spe
42. ECIFICATION MM NE 31 CHECKOUT amp ACCEPTANCE PROCEDURE ____ _____ E DEREN NUNC MEE L 21 POWER SUPPLY amp REGULATOR ASSY BOE eed RENE OoOo O p MN p ee pm ae a a O REV 5 5 7 6 5 3 2 LEGEND NOTES VARIATION D 37 I FOR DWG INDEX LIST REFER 15 VAC 0 01 4 2 2 j Pe 230 VAC leer MEAE E j e BOTH TRACKS USE VB DRILL 15 24 iil PLAC ITEM 55 ON WU Aa oun T T B ve VRI4 C 4 29 NS ws 71 weed USED TH VRI4 LC LD REF nmmn u EE G840 LIGHT PEN OPTION d 50 60 uz BINNEN WHEN KEYBOARD IS CONNECTED THERE IS SU ER COVER x IO We top I fi i INBUT CONNECTOR is 0 DEM 9 M 67 WITH SECTION 6 25 REF gt TTEM S 66 69 55 FROM TOP P SCREW OF CONTROL PANEL TO GND p ue o B on m 9 FOR VRI4 S LC LD ROTATE YOKE S e M mu M 1 lt 2 B
43. ED JOR EQUIPMENT n B az UNLESS OTHERWISE SPECIFIED CORPORATION Q WENES MAYNARD MASSACHUSETTS E gt INT AIE INT2 2 NO suaract SCHEMATIC VRI4 NUMBER IC VRI4 O 1 FISHMAN CC C 2 21 CHANGE NO Z NEXT HIGHER ASSY A ML VRI4 CALE NONE CHANNEL SELECT SWITCH NOTE CHANNEL SELECT SWITCH NOT USED WITH VRI4 LC LD 209 VRIA OO c REV 3 s E 22 VRI4 00021 4 00019 4 2 5 27 o L 1 1 7 6 5 4 3 A a TEATS 2 of Cquinement Cosposetpoa sad shal net slg R33 Iw 2 SEN AK OK 02 UNLESS OTHERWISE INDICATED R34 Ds zu 0 1 ALL CAPS ARE 5 270 C13 I PF 47534 C9 SW ALL RESISTORS ARE 1 0K I 4W 57 F is D w 812 62 680 Q2 ALL DIODES ARE 0664 Ny SIND vUa RE 207 2N2904A CI ona 99 3 8w RY uS D qj NASSA 823 DEFLECTION AMPLIFIER X RI R2 TO D 47 MAINTAINANCE DRAWING CHANGED TO 3 3K RI lt 2215 yaw 5 vec e 1300439 FOR 8 4 14 RIS YOKE ASSY INPUT SIGNALS INPUT SK tow R
44. IC VR 4 JE A225 COMMERS OO on 5 tv MATERIAL 5 NEXT HIGHER AIN Z POSITION VAC SAMPLE TTE i z ICI VRI4 1 J ae None 3 FEEDBACK eee e skeer 2 o3 G Fi i 8 7 5 T 4 3 2 E 5 29 CODE NUMBER VRIA4 9 1 Bi o 7 6 5 4 3 2 D w x R s 1 RAW 20 AL2 SENSE RAW 2 013 014 IN40Q 4001 5W 2 BRIGHTNESS REG 3 852 2 0 T IN752A I5V D3 10 4004 02 iu GNC SENSE IK GNO BDZ Y v sts VII sss RAW 2 V 016 Inge 2 83155 SENSE 1 2W 107 BE2 4399 SUPPLY REGULATOR MAINTAINANCE DRAWING CODE gt EYELETS BL2 GND SENSE FIPST USED ON OPTION MOO VRI4 UNLESS OTHERWISE SPECIFIED UNLESS OTHERWISE SPECIFIED DIMENSION 1M INCHES TOLE ES DECIMALS ANGLES gt 4 x 20 FINAL SURFAQI QUALITY REMOVE BREAK DESCRIPTION PART NO baw b um EQUIPMENT RENI CORPORATION 9 SCHEMATIC BI iu vee 8 7 6 5 5 31 eo z 9 e gt REV This drawing and specifications herein
45. ION e HE A SINK DEC EIA DEC EIA 0 0 7007080 0 0 rr 5302 2N5302 CODE NUMBER REV DEC 3794125 3796 Eur es 1007080 0 pl Eb ee o st TT T 1 2 1 5 61 8 7 6 5 4 3 5 0 0 280200 00 2 1 This drawing and specifications herein the W E ZA B L E NOTES erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as wien em LITEM DESCRIPTION TO 4 REF USE TIE WRAPS WHEREVER NECESSARY COLOR CONNECTION W 7H CONNECTION WITH RED BRADY r a k keyra 4 2 2 Pl Pf 5 8 Fi f leas 4 Pf 4 RC D Pf _ 2 lt 0 5 ers 2 9 76 fee 4 E aes mI 587 ivo e 9 lt 2 n 10 _7 J erra gp 2 lt 5 2 13 8 BRADY m ro P LI DETAIL AC 70 4 9 x SEE NOTE SEE DETAIL 3 4 5 4 400 3 EE REF Oly 8 P 10 ea eee ee E 5 2 REF m E 7 REF 2 Q io s REF 2 PEF 4 CREF DESCRIPTION PART NO PARTS LIST FIRST USED ON OPTION MODEL DO NOT SCALE DRAWING m DATE rA EQUIPMENT
46. ITCH REG VR29 230 VAC WHT VIO ORN TR 5 FI GNO 96 F Y 2 CRT ANODE vRI4 TO H V SWITCH REG VR2Q EQUIPMENT CORPORATION AALAND 548 82699646776 CIRCUIT SCHEMATIC NICHER ASSY PWR SUP Sl7o07084 0 1 e ud 2 2 sr T T LI L i L l L 3 2 1 5 81 D CS 7007084 J APPENDIX POWER SUPPLY TROUBLESHOOTING NOTE The power regulator heat sink contains a thermal cutout connected to the input line voltage Always remove the line cord before handling the heat sink Generally if the 320V reads above 25V one both of the regulator transistors has shorted The 20V is controlled by the PNPs 2N4399 that the front set of transistors on the regulator heat sink as viewed from the front of the VR14 The 20V is controlled by the NPNs 2N5302 on the rear section of the regulator heat sink 1f after replacing the power transistors the problem is not corrected the G836 board itself is suspect If the regulator circuits are not working the output could be beyond its nominal value The MC1709 is most likely suspect followed by the drive tran sistors 2N4923 for 20V and 2N4920 for 20 If on the other hand the 20 read zero the same power transistors are still suspect they may be open Al
47. LES Title Rear Connector Pin Assignments Control Settings Engineering Drawings Page Page 1 4 2 2 2 4 2 6 3 3 3 9 3 13 3 16 4 2 4 7 4 9 4 10 4 11 2 4 2 9 5 1 WARNING Maintenance procedures should be performed by qualified service personnel only High voltages are present within the unit and under certain conditions are potentially dangerous All electrical safety precautions must be observed Inherent implosion protection is employed in the CRT design however the tube may be damaged if it is subjected to rough treatment or dropped while being removed from or installed in the display Exercise caution during these operations FDCBL 12 1 91 FOR I 095 1 38 02 1 61 92 SET 99 z FEXPLC O I FSINC 9 12 0 D xg CHAPTER 1 GENERAL INFORMATION 1 1 GENERAL DESCRIPTION The VR14 is a completely self contained CRT display that provides 6 75 in x 9 in viewing area in a compact 19 package The 14 requires only analog X and Y position information and an intensity pulse to generate sharp bright point plot displays Except for the CRT itself the unit is composed of all solid state circuits utilizing high speed magnetic deflection to enhance brightness and resolution The inputs for the X and Y deflection may be balanced or single ended bipolar offset and positive negative going without any modification to the 14 The intensity puls
48. Lu ala al DEC 16 325 1031 870 C FORM A 110 5 21 8 7 __6 5 4 3 p o This drawing and specifications herein are the prop erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without written permission D 77 9252 6 E gt 1 758520 5 PEF 74 7 gt 76 2 52 6 2 REF B REF 20607 6 wenesme ir 6 77 16 O 9 fT FARSDE REF aN 20 O O DESCRIPTION ____ PARTNO IRST USED OPTION MODEL DO NOT SCALE DRAWING DRN DATE EQUIPMENT VRI4 UNLESS OTHERWISE SPECIFIED I UR 0 21 CORPORATION n DIMENSION IN INCHES CN 2 22 DAE o MAYNARD MASSACHUSETTS 2 5 kX vlo lt N M TOLLRANCE 5 VERE enero ANGLES Jm ELS DECIMAL sone gun 7 MTG ASSY 2 E XX 2 005 REMOVE BURRS AND BREAK SHARP 144 f mi 5 uum CORNERS JPROD ____ DAT X f HIGHER 55 IT 5 2 4g ve Z g CODE NUMBER REV FINISH AD 7007077 0 0 SESE Te 7 DEG FORM sHeeT orz TG 7 6 5 4 3 2 5 23 a REVISIONS CHANGE NO x DEC FORM
49. OS NEG 2 5 36 47 18 19 20 21 22 28 24 O O O O O O O O O lC P AMPHENOL 24 CONTACT CONN POS NEG CAP 2 DHRECT 7 INPUT _ L 2 E 52 A A A A POT V i V V N V t V V V V 6840 W684 6858 A225 A225 W682 FAULT 7 PROTECTION X AMP Y AMP INTENSIT Y NOTE ALL ABOVE PARTS SHOWN ARE VIEWED FROM WIRING SIDE PLUGS INTO JI5 ON 6840 FIRST USED ON OPTION MOO cathe UNLESS OTHERWISE SPECIFIED IANUE EQUIPMENT Y f 144 UNLESS OTHERW SE SPECIFIED AY 19 CORPORATION ICH TS Pio TOLERANCES 1 23 70 DECIMALS FRACTIONS ANGLES robbs 0 70 V 4 005 1 64 0 30 FINAL SURFACE QUALITY ENG DAT REMOVE BURRS AND AREAK lie 044 CORNERS PROD MAYNARD MASSACHUSETTS DISPLAY ASSY s we d MATERIAL NEXT HIGHER ASSY D UA VRI4 9 Q DUAL abo coe UAVRIA O O eee sheer 3 111111 5 4 ole 3 2 1 5 11 gt BRUNING 40 107 15968 8 7 6 5 4 3 This drawing and specifications herein erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without written permission 97 a 0 2 z n DIMA 2 1
50. PLAY ASSY 100 VAC D UA VR14 B B VR14 C DISPLAY ASSY 15 VAC SUPER COVER D UA VRI4 C VR14 LC DISPLAY ASSY 115 VAC MODIFIED FOR GT 40 D UA VR14 LC VR14 LD DISPLAY ASSY 230 VAC MODIFIED FOR GT40 D UA VR14 LD PANEL FRONT PANEL FRONT LIGHT PEN 1 7409974 0 0 FOR PDP 12 USE LIGHT PEN ASSY LIGHT PEN 1 7409977 0 0 FOR 6740 USE 15 375 0 0 B DD 375 f PANEL FRONT LIGHT PEN 1 7409068 0 0 LIGHT 375 C UA 375 A B B DD 375 A SUPER COVER ASS Y 07009027 0 _ DESCRIPTION No pRoD cusT F _ m m E gt zQ T V SIZE CODE LIGHT ASSY C UA 375 g PHONE JACK CABLE D 14 7008433 f B LIGHT PEN ASSY C UA 375 A B 375 JACK ASSY C IA 7009170 B p TINI PLUG 375 A PANEL FRONT LIGHT PEN 14 7409068 0 0 SILK SCREEN 55 7409068 0 1 PANEL FRONT LIGHT C 14 7409977 g 4 SILK SCREEN B SS 7409977 9 1 PANEL FRONT LIGHT PEN 14 7409974 0 0 SILK SCREEN B SS 7409974 g 1 SUPER COVER ASSY 0 0 7009027 0 0 SHIM CHASSIS R H C MD 7409968 0 0 SHIM CHASSIS L H C MB 7409969 0 0 COVER PANEL REAR TOP D MD 7409965 0 0 EXTRUSION ASSY LOWER D 1A 7409972 0 0 COVER TOP E 1A 7409963 0 0 OPTIONAL 4 RST USED OPTION MODEL JORN EQUIPMENT z oce iE 23 70 VRI4
51. PUT z SELECT NOTE BEOVE PTS SHOWN BLE gt FROM WRING sar FIRST USED ON OPTION MODEL DO NOT SCALE DRAWING UNLESS OTHERWISE SPECIFIED DIMENSION IN INCHES TOLERANCES DECIMALS FRACTIONS ANGLES VRI4 1 64 CORNERS FINAL SURFACE QUALITY REMOVE BURRS AND BREAK SHARP 0 30 MATERIAL FINISH _ PARTS LIST EQUIPMENT K kI 222 2252 75 4 0 2 20 jul Wh 4 FP Patra VRI4 HIGHER 52 D 49 0 4 2 CODE NUMBER REV 70070 7 7 O O 1 2 1 MAYNARD MASSACHUSETTS TOP MTG ASSY 5 25 REV m z a3 z O N Q O SIZE Bis 1 O DIYA 7 6 5 4 LI and heren prap JIS PIS ee ae 2222252 _ e tha enclaves Si DEN el AUAI LICHT PEN pension 1972 50 WHI A4 AIH REMOTE 5836 2 6 BUS 6840 e9 i D A2D i U 25 5 PS A INPUT RED XIN 225 IO e ERN TL 5 m 4 e 2 2 2 2 B 2 _ B 5 c ub YEL BLK X GND AMPHENOL 24 PIN 6 gt gt CONN EN
52. T YOKE ASSY 0 14 7007088 0 0 DEFLECTION H S ASSY 0 40 7007082 0 0 DEFLECTION ASSY 0 0 7007083 0 0 VRI4 CONTINUED ON SHEET 2 OF 2 4 3 MECHANICAL DEPT USAGE Es VR14 DISPLAY ASSY 115 4 DISPLAY ASSY 230 VAC 14 DISPLAY ASSY 100 VAC VR14 C DISPLAY 115 VAC S C VR14 D DISPLAY 230 VAC S C 4 DISPLAY 100 VAC S C VR14 LC DISPLAY ASSY 115 VAC GT 40 VR14 LD DISPLAY ASSY 230 VAC GT 40 VR14 DISPLAY ASSY P L BEZEL 2 BEZEL CONTROL PANEL VR12 CAP REAR CAP 4 MASK C R T VRIA MASK C R T SCREEN SAFETY SCREEN SAFETY 4 PLATE BOTTOM MTG FAN SCREEN C R T SHIELD MAIN CHASSIS CABLE HARNESS GROUND TUBE CHASSIS TRACK BRACE CHANNEL SWITCH MASK BRACE CHASSIS SHIELD SAFETY HOLDER CARD PKG INST VR14 RACK MOUNT PKG INST VR14 SUPER COVER JUMPER TOP MTG ASSY TOP MTG ASSY P L PLATE TOP MTG SCOTCHCALS VR14 PANEL CONTROL PANEL CONTROL SILK SCREEN WIRED ASSY WIRED ASSY P L FRAME LOGIC BAR MTG LOGIC FRAME DECALS LOGIC FRAME DECALS C R T YOKE ASSY HIGH VOLTAGE ASSY HIGH VOLTAGE ASSY P L PLATE HIGH VOLTAGE MTG SHIELD HIGH VOL PROTECTION SPACER HEX HIGH VOLTAGE SHIELD POWER REGULATOR ASSY VR14 POWER REG ASSY VR14 P L MATE N LOK ASSY BRKT COVER CAPACITOR 6836 POWER REG ASSY 5836 POWER REG ASSY P L POWER SUPPLY H S ASSY POWER SUPPLY H S ASSY P L
53. UED E DATE LQ ID ATE M DWG PART DESCRIPTION 7007081 1 0 REGULATOR HEAT SINK ASSY d SPACER SOCKET HOUSING MATE N LOK CLAMP NYLON I D SCR PHL HD PAN 46 32 x 5 16 LG WASHER FLAT 46 SST SCR PHL HD PAN 46 32 x LG SST WASHER INTERNAL 46 32 SST 0 TIE WRAPS SST 1B REGULATOR HEAT SINK ASSY C MD 7408437 0 0 BRKT MTG SPACER Plo J 9 zal 4 O gt 4 lt i mr r m O IT ASSY NO P S HEAT SINK ASSY D AD 7007080 0 0 HEET 1 OF E NUMBER REV ECO NO 7007080 0 0 o T 4 r DEC FORM 16 1031 DRA 110 HEAT SINK CONNECTOR SOCKET HOUSING DEC 1209351 42 ORN RED I BLU G Y N G4 TRANSISTOR DEC 5502 510196 p CHEER RI R4 RESISTOR SW 51 1305872 a EQUIPMENT UNLESS OTHERWISE SPECIFIED 46627 522222 CORPORATION DIMENSION IN INCHES MAYMARO MASSACHUSETTS TOLERANCES 2 4 4 WAA R3 lt 1 5 54 849 ln5W 51 94 DEC 5502 m P3 AMP I2 CIRCUIT 1209351 12 Tu 39 TITLE kok BEN ANGLES 0285 gt 0 30 gt REVISIONS CHANGE NO SURFACE QUALITY lt 27 CIRCUIT SCHEMATIC CORNERS PRO D I TRANSISTOREDIODE CONVERS
54. URE WIRED ASSY WIRED ASSY P L G836 POWER REG ASSY 0836 POWER REG ASSY P L CIRCUIT SCHEMATIC 0836 POWER SUPPLY HEAT SINK ASSY POWER SUPPLY H S ASSY PL CIRCUIT SCHEMATIC HEAT SINK DEFLECTION HEAT SINK ASSY DEFLECTION H S ASSY P L CIRCUIT SCHEMATIC DEFLECTION POWER SUPPLY ASSY POWER SUPPLY ASSY P L CIRCUIT SCHEMATIC POWER SUPPLY ON OPTION MODEL DRN FIRST USED OPTIO D bK CRABBE P VRIA ay K CRAEFE 11 24 77 DK 2 PART NO PRoD cusT 1007078 7007078 1 TITLE 6G836 9 9 6836 0 6836 0 1 1007080 0 1007080 7007080 1007082 1007082 1007082 1007084 1007084 1007084 0 B p c VI ET pe T 5 pe ve EQUIPMENT CORPORATION MAYNARD MASSACHUSETTS DRAWING TR u sa NEXT HIGHER ASSY D UA VRIA INDEX LIST REV A ms s XT 2 1 5 33 IT Id 2 1 ELECTRICAL DEPT USAGE 8 7 6 5 _ 4 DEPT USAGE This drawing and specifications herein are the prop erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without written permission 7 VR14 DISPLAY ASSY 115 VAC D UA VR14 9 g VR14 A DISPLAY ASSY 230 VAC D UA VR14 A 8 VR14 B DIS
55. ack and the reference ground for the regulator If the regulator simply monitored its regulated voltage at the G836 circuit board voltage drops across the wires carrying the current to the deflection amplifier could not be cancelled By tying the sense leads at the deflection amplifier 20V is maintained where it is needed at the load deflection amplifier The output power transistors are current limited by D13 D14 These diodes conduct whenever excess ive collector current is demanded In so doing the diodes limit the base drive thereby limiting the maximum fault current that may flow 3 3 CRT ELECTRODE VOLTAGES The CRT electrode voltages are the filament cathode grid 1 grid 2 focus and anode The filament is simply a step down winding on the power transformer that delivers 6 3 Vac directly to the filament cathode and grid 1 bias voltages are generated from a 35 Vrms winding on the power transformer This winding terminates on the G836 see Figure 3 2 Through D11 C17 R36 and C16 this winding generates a 80 Vdc by half wave rectification The same wi nding in like manner generates 80 from D12 C18 R37 and C19 The 80V is applied to one side of the front panel brightness potenti ometer The wiper of this potentiometer goes to grid 1 and the remaining side of the potentiometer returns to the brightness preset potentiometer R38 R38 sets the maximum positive value the front panel potentiometer can achieve Th
56. adjustments are accessible through the top of the see Figure 2 3 On the rack mounted model the unit is moved forward on the chassis slides until the adjustments can be reached The table top model has access holes though the top of the case only for position and gain Access for focus and brightness preset is gained by removing the case cover POSITION 21 I Hum 71 BRIGHTNESS GAIN E 0 T PRESET HORIZONTAL VERTICAL FOCUS Figure 2 3 VR14 Top View The gain and position adjustments are located on the top left central portion of the VR14 as viewed from the front The two forward potentiometers on the deflection circuits are the horizontal gain on the left the vertical gain on the right The two rear potentiometers are the horizontal position on the left the vertical position on the right The gain adjustments allow the VR14 to accommodate a range of input signal amplitudes and expand or contract the horizontal and vertical deflection to suit full screen requirements The position controls accommodate a variety of input signals and allow offset inputs to be centered on the CRT screen Once initially adjusted for the particular input signals used the gain and position controls will rarely to be adjusted Gross positioning off screen or exces sive gain deflecting off the extremities of the screen should be avoided since the deflection amplifiers will go into current limiting and may overh
57. bleeder resistor CRT is fully enclosed in a magnetic shield Unit is protected against fan failure or air blockage by thermal cutouts Power supply and amplifiers current limited Phosphor protection is provided against fault conditions a Deflection Amplifiers are dc coupled and are capable of sustaining a full screen ac or dc deflection at environmental extremes b Input Specifications 1 Inputs are differential Differential input impedance 5k Q minimum 2 3 Input sensitivity 500 mV in maximum 200 mV in with resistor change 4 Common Mode Rejection Ratio 40 dB 5 Maximum operating input 6V Maximum operating input is the sum of the common mode input and the differential input Input offset not to exceed 1 2 peak to peak input signal Maximum nonoperating input 50 c Full screen deflection and settling time to within spot diameter 18 us d Small signal settling time to within 1 2 spot diameter 1 ys for a 0 1 deflection e Small signal linear slew rate 20 4 in 1 ps f Velocity error coefficient 500 ns maximum Average ramp delay between input and output 1 2 Z Axis Power Z Input A negative transition from gt 2 4V but not exceeding 48V to lt 0 8 but not more negative than 4 in 2 20 ns will cause an unblanking pulse at the CRT cathode from approximately 60V to ground with a duration of Z 200 ns at the 50 percent points Delay between the 50
58. cifications Block Diagram Description OPERATION Installation Front Panel Controls Rear Panel Controls and Connectors Internal Controls Input Signal Requirements THEORY OF OPERATION and Y Deflection Circuits Plus and Minus Low Voltage Regulated Supply CRT Electrode Voltages High Voltage Power Supply Intensity Circuit MAIN TENANCE Preventive Maintenance Troubl eshooting No Picture Faulty Picture Assembly Replacement Instructions Deflection Heat Sink Removal 7007165 Power Regulator Assembly Removal Regulator Heat Sink Removal Yoke and CRT Removal High Voltage Supply Removal Page 3 7 3 12 3 12 3 14 4 1 4 3 4 5 4 6 4 6 4 8 4 8 4 9 4 13 CONTENTS Cont APPENDIX POWER SUPPLY TROUBLESHOOTING APPENDIX DEFLECTION AMPLIFIER TROUBLESHOOTING APPENDIX C A225 REPAIR CHAPTER 5 ENGINEERING DRAWINGS Figure 1 1 2 1 2 2 2 3 3 1 3 2 3 3 3 4 4 1 4 2 4 3 4 4 4 5 Table 2 1 2 2 5 1 ILLUSTRATIONS Title Art No VR14 Block Diagram Input Power Jumper Rear View 5481 24 VR14 Top View 5481 1 X and Y Deflection Circuit G836 Circuit Board Part of The 7007165 Power Regulator Assembly Intensity Amplifier W682 Circuit Schematic Circuit Diagram C838 Voltage Chart Deflection Heat Sink Removal 5481 15 5481 20 7007165 Power Regulator Assembly 7007165 Removal 5481 3 5481 8 Regulator Heat Sink Removal 5481 13 5481 18 TAB
59. ctly the way the signal comes in This is accomplished with R9 The position signal is nothing more than an adjustable dc level from R8 which through R9 adds or subtracts voltage from the actual input signal This allows the displayed information to move up down left right on the screen or in the case of offset input signals allows the information to be centered on the screen The remaining component on the A225 is frequency compensation which allows the amplifier to operate over its required bandwidth without oscillation Because the amplifier must operate from dc to beyond MHz the voltage gain must be reduced continuously at higher and higher frequencies If this were not done excessive phase shift between input and output from feedback could cause the output to be in phase with the input and thus oscillate R12 C15 and R32 and C16 R3 and C11 perform the required gain reduction functions R12 reduces the open loop gain of E2 at all frequencies C11 reduces the gain of Q2 at high frequencies and is of major significance to the overall bandwidth The yoke itself represents a major roll off for the amplifier and its high frequency characteristics dominate the stability of the amplifier An RC network across the yoke enhances the high frequency settling characteristics of the yoke The power output stage 2N5302 and 2N4399 is current limited by the 20 and 20V power supply regulators If the deflection amplifiers are driven way of
60. d specifications herein the erty of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without written permission 972 HARNESS TABLE COLOR CHASSIS LOC qu U 7 p mm AGL 2 404 WHT VI 13 BRN I B 4B N BRN 20 4 22 5049 M ORN 25 en o c BLK 35 SE T M i DRY GRN 58 59 DRY BRN 60 NHT SRN 8 NHTARN 82 ERN RED REVISIONS CHANGE NO x I DEC FORM DRD 100 8 O HARN EOS BLE CONT BOIN BLU 89 604 GRYORN 90 RED 9 AGE YEL 96 ABH O BLK RED 98 POS BEK 99 2 POS BLU 2 6 _______ BLK IOI POINT 104 6 WHI BLU 105 BLK 106 C GND POIN CLEAR IOTA FNPUT wHUvIO 108 SELECT 109 Z INPUT GND 110 Z DIRECT SHIELD SHIELD SHIELD __ VIO A 4V PI TS BLK IOIB RED RED 02C BLU 96E CAP 2 NEG 2 BNC L TOP D P
61. de of the potentiometer goes to 80 The wiper goes to the focus electrode on the Because of CRT manufacturing tolerances proper focus may occur from unit to unit anywhere between 80 and 400 The focus potentiometer has sufficient range to accommodate any 12M63 CRT The anode is supplied 11 5 kV from the high voltage supply 3 4 HIGH VOLTAGE POWER SUPPLY The high voltage supply is a self contained high voltage source that requires only line voltage input The input is actually the split primary of its own internal step up transformer For 115V operation the primary windings are operated in parallel for 230V operation they are operated in series The step up transformer delivers high voltage ac to a voltage doubler and filter The ultimate de voltage EL Z SIGNAL J RI IOO CI 6 8 MFD 35V 10 Wu Z SELECT L R3 00 RIO 100K Z DIRECT INPUT 0 UNLESS OTHERWISE INDICATED DIODES ARE D664 CAPACITORS ARE IO0V 20 El 15 DEC7400N PIN 7 ON IC GND PIN I4 ON IC 5V RESISTORS ARE I 4W 10 DI3 015 3 06 0662 0662 CHANNEL SELECT SWITCH F TO SWITCH AUTO MAN E TO BRIGHTNESS POT SLIDER Figure 3 3 Intensity Amplifier W682 Circuit Schematic 017 IN4757 2112 330 07 060 014 IN3039B is 11 5 kV and unregulated Thus the high voltage is slaved to the line voltage i e when the line is 105 Vac the high voltage is 10 5 kV when the line
62. e be time multiplexed or gated by a separate input to allow the screen to be timeshared between two inputs VR14 construction is modular for easy maintenance Any subassembly or major component can be re placed in minutes using only a screwdriver The VRIA is available in a standard 19 in rack mounted unit or in a free standing table top version 1 2 SPECIFICATIONS VR14 Specifications are as follows Physical Height 10 172 in Width 19 in Depth 17 in Weight 75 lb Viewable Area 6 3 4 in x 9 in Spot Size lt 20 mils inside the usable screen area at a brightness of 30 fL Jitter x 1 2 spot diameter Repeatability lt spot diameter Repeatability is the deviation from the nominal location of any given spot Gain Change Temperature Range Relative Humidity Brightness Linearity Deflection Method Focus Method High Voltage Shielding Overlaod Protection Deflection Amplifier From a fixed point on the screen less than 0 396 gain change for each 190 line voltage variation 0 C to 50 C operating 1096 to 9096 noncondensing gt 30 fL measured using a shrinking raster technique Maximum deviation of any straight line will be lt 196 of the line length measured perpendicular to a best fit straight line Magnetic 70 diagonal deflection angle Electrostatic 10 5 kV dc nominal voltage proportional to input line voltage Supply is self contained and equipped with a
63. e front panel potentiometer when turned full counterclockwise connects the wiper and grid 1 to 80V cutting the CRT beam off completely As the potentiometer is turned clockwise grid 1 becomes less negative or more positive the maximum value by setting R38 on the G836 Intensity on the screen is generated by cathode pulses from the W682 card When not intensifying the cathode is held at 60 The 60V is derived from the 80 at the W682 board see Figure 3 3 When the beam is to be turned on the 60V on the cathode is grounded or made However this alone does not determine brightness since intensity 15 related to grid to cathode voltage Thus the cathode is constantly going between 60V and OV but depend ing on where the grid voltage brightness potentiometer is set the beam may never be on dim or very bright Grid 2 of the CRT is operated at approximately 400 Vdc The 400V are generated by a voltage doubler on the G836 board The ac passes through C4 and is prevented from going negative by D9 This causes the entire peak to peak voltage to become positive DIO rectifies this voltage and C15 filters the resultant output is 400 The 400 goes directly to G2 If G2 is not substantially positive ly biased the CRT beam can never be turned on regardless of how much grid to cathode drive occurs The 400 Vdc also goes to side of the focus potentiometer R35 on the 5836 board The other si
64. e oe 2 Scale lt 25 70070 82 0 Ew ie EXER H sur o o T IIT IL T L 4 3 2 5 67 5 5 4 3 Se rsozooz oda 2 7 rea gere eMe LEGEND T 15 25 REF a sale of items without N U M B E R VA T N 7007084 115 VAC 50 60 HZ d 17007084 2 230 50 6 2 qo Xu 7007084 3 I VAC 50 60HZ ru pp C zi 7007084 4 115 VAC VR2G ERES 7007084 5 230 VAC VR2 A D 7007084 6 199 VAC VR20 4 42 VA n 38 2 2722 Vla 46 46 SS Vas SA Do TTE 1 O gt 9 0B REF 84 0 0 2017007 4 REF a OO NOT SCALE DRAWING PAE EQUIPMENT eh de UNLESS OTHERWISE SPECIFIED 70 20 70 CORPORATION INI Pc TOLERANCES Ni m DATE Ab bs 1 Lis ANGLES PAA 2555 x pae tapet 8019 JHERERIERSEBRBERERSNERE CUN 2 Siu SEEN D i zi a 855 REMOVE SHARP PROD ASSY iV R 4
65. e of equal duration with the Z intensify By varying the amplitude and polarity of the Z direct pulse the dot will be of a different brightness When using Z direct without the Z intensify such as for vector intensity control or any other nonpoint plotting application the signal must be large enough to overcome the CRT cutoff typical direct signal will have 5V to 10V of actual brighness infor mation riding on top of a 40V pedestal the 40V pedestal insures that the CRT will reside below cut off The Z select works in conjunction with the front panel channel select switch The Z select allows the Z intensify pulse to be gated or time multiplexed When the channel select switch is on the 1 and 2 position Z select inputs have no affect on the VR14 When the channel select switch is in the 1 position Z intensification occurs only when Z select input is a TTL high When the channel select switch is at 2 Z intensification occurs only when Z select is held at a TTL low Thus if two separate pieces of information are to be displayed by placing Z select at a high only during channel intensification times and low only during channel 2 intensification times both curves will be displayed when the channel select switch is at 1 amp 2 and only channel 1 when channel 1 is selected and channel 2 when channel 2 is selected 3 3 X AND Y DEFLECTION CIRCUITS The X and Y deflection circuits a
66. e unipolar input signal the offset and input will aid driving the deflection into current limit off screen INPUT POLARITY Figure 2 2 VR14 Rear View Table 2 1 Rear Connector Pin Assignments Function Z Select High input enables Z intensify to occur if channel select switch on 1 A low input enables Z intensify to occur if channel select switch on 2 Chassis ground Chassis ground When this input goes from high to low an intensity pulse is generated Table 2 1 Cont Rear Connector Pin Assignments Chassis ground Chassis ground X Input One side of the X input signal line X Input Other side of the X input signal line or ground for single ended inputs X input Shell Shield or signal reference ground for X input Y Input One side of the Y input signal line Y Input Other side of the Y input signal line ground for single ended input Y Input Shell Shield or signal reference ground for Y input Z Direct Input signal that directly modulates CRT grid ac coupled Chassis ground Chassis ground Not used assigned for VR14 options Not used assigned for VR14 options Not used assigned for VR14 options Light Pen output only on VRIAL Light Pen output only on 141 Chassis ground only on VR14L Not used Not used Not used 2 4 INTERNAL CONTROLS The VR14 internal adjustments include six potentiometers X position X gain Y position Y gain focus and brightness preset
67. ead between the screwdriver blade and chassis plus a second clip lead for safety is adequate slide the blade under the rubber cup on the high voltage connection at the CRT and touch the anode connection to discharge any remaining high voltage At the same time remove the high voltage connection The connection is made by two stiff wires that each have a bend or hook on the end The connection at the CRT is made by squeezing these two wires to gether so they can fit in the CRT metallic hole Then these two wires are let go so they can expand and grab the inner lip of the CRT with the hooked ends The connection is removed by squeez ing the hook wires together and at the same time pulling them out so that the wires can clear the anode hole Remove the CRT plastic mask by removing the top and bottom screws from the front bezel casting The CRT is held by four screws one in each corner of its shell bond frame each screw is removed support the weight of the CRT CAUTION The CRT is under high vacuum and is po tentially in danger of explosion if subjected to sharp blows or very rough handling Also to avoid dropping the CRT accidentally never place your hand over the anode high voltage button while picking up or carrying the CRT in case the CRT has residual charge The shock is not in itself dangerous but the surprise may cause the user to drop the CRT Never hold the CRT by the neck the thin cylindrical portion alone since
68. eat if allowed to stay in this condition any length of time Turning the X and Y gain controls clockwise increases the gain or displayed image size Turning the X and Y positions clockwise moves the displayed information left and down respectively 2 6 The focus and brightness preset adjustments are located at the top right central portion of the unit They are on the power supply regulator circuit G836 that is somewhat recessed from the top of the unit The brightness preset is the rear of the two This potentiometer allows the range of the front panel brightness control to be limited to any maximum brightness desired Turning the brightness preset counter clockwise increases the maximum brightness range of the front panel control Generally this control is set so that at maximum brightness setting on the front panel knob the displayed in formation does not bloom causing a degradation in resolution The focus potentiometer is in front of the brightness preset The adjustment is quite insensitive and requires several turns to go through focus 2 5 INPUT SIGNAL REQUIREMENTS NOTE The deflection amplifiers must not be driven so that the CRT beam is off screen for any length of time or permanent damage may occur Ensure that input deflection signals fail to a safe on screen value The VR14 requires analog voltage inputs for the X and Y deflection and a logic level change pulse for intensify The X and Y inputs are ide
69. er transistors drive the deflection yoke that positions the electron beam on the screen The yoke currents are then passed through a 0 5 ohm resistor that con verts the yoke currents back into voltages that are used as feedback for each A225 deflection amplifier 1 3 FROM THERMAL CUTOUT 445 gt ho VAC INPUT 115 20V PASS 20V PASS THERMAL 115 TRANSISTORS TRANSISTORS CUTOUT UNIT POWER 115 115VAC RECTIFIERS 20V FILTER CAP 20V HIGH POWER iu amp FOCUS VOLTAGE REGULATOR BOARD POWER TRANSFORMER G836 400 SUPPLY 80V 10 500VDC CHANNEL Duci e edi o T lll DEFLECTION CHANNEL Y BRIGHTNESS Focus CHANNEL 1 PRESET 7 2 INTENSITY INTENSITY wees 80V FEEDBACK PROTECTION 2 GAIN CURRENT 20V 6838 A uH X DEFLECTION X INPUT gt lt AMPLIFIER a 20v TRANSISTOR 20V POLARITY Y Y INPUT DEFLECTION AMPLIFIER A225 0 5 0 CURRENT SAMPLE Y FEEDBACK 1 12 0332 Figure 1 1 VR14 Block Diagram This feedback allows the A225 to produce an exact current replica in the yoke of the input signals The intensity input is applied to the W682 circuit board that converts this input to a 60V pulse which drives the cathode The cathode pulse is negative going this pulse turns on the electron beam cre ating a spot on the screen The W682 accepts a gating input that allows the in
70. f screen the power supply limits the maxi mum current to 11 amps If this condition is allowed to exist eventually either the 20V fuse or the 20V fuse will blow rendering the circuit safe from such overloads 3 2 PLUS AND MINUS LOW VOLTAGE REGULATED SUPPLY The input line voltage is stepped down in the power transformer to approximately 30V rms There are two identical secondary windings to deliver these 30V Both windings are connected in series making a 60V center tapped winding Using full wave bridge rectification the ac becomes approximately 70 By grounding the center tap these 70 split evenly with respect to ground thus 35V and a 35V are available with respect to ground filter capacitor on each 35V line smooths the ripple and finishes the task of generating the raw unregulated dc for the 20V regulators The regulators are contained on the G836 circuit board see Figure 3 2 and the heat sink adjacent to the G836 Since the 20V regulators are symmetrical only the negative regulator is described raw 20V actually 35V is dropped by R33 and R34 and preregulated with D5 and D to 12 Vdc and D7 and D8 to 12 Vdc The 12 are the voltages necessary to operate and E2 they are also used to generate the refer ence voltage with which the output voltage will be compared The reference for the 20V regulator AM2 22V RAW 22V D13 D14 4001 IN4001 167 SN
71. g may be done with a volt ohm milliampere meter and most tests can be done with a however more exacting information can be seen with an oscilloscope NOTE When making voltage measurements on a malfunctioning VR14 set the voltmeter or oscilloscope to the proper range connect the leads to the test points then turn the power on and off very quickly so that the anticipated reading may be taken Power is only on for a very brief moment In this way fault conditions may be discovered without causing further damage Never leave power on to malfunctioning or repaired VR14 until all necessary checkpoints are measured and proved nominal see Figure 4 1 The circuit card connector block as viewed from the wiring side is labeled A01 to A04 left to right on the top section and to 804 on the bottom section 4 1 Circuir Block A03E B A01U B01V AOTK BOIR BOAB B04D 4 B04J 8041 2 2V nominal 2 2V nominal 22 Vdc red 22 Vdc blue 5 3 5 Vrms 3 5 Vrms 380 80 80 to 400 60V Brightness Potentiometer Gray Green Deflection Heat Sink P5 X AXIS P5 2 5 1 5 3 5 4 5 Regulator Heat Sink P3 1 P3 2 P3 3 12 P3 11 P3 10 Y AXIS P5 14 P5 15 P5 P5 12 5 11 80 21 22 lt V 21
72. he three preceding measurements are good and the 682 output measured at BO4 L is not going from 60V to for at least 300 ns repair or replace the W682 module Continued on next page 4 4 Step Procedure 10 Measure 6 3 between B04 A B observe the glowing filament on the CRT No 6 3 can be traced back to the G836 circuit board which routes the 6 3 Vac from the transformer 11 Measure the grid 1 voltage at 04 It should vary from 80 22 to between 20V and OV when the front panel brightness control is varied The 80 Vdc comes from the G836 board Trace back to the G836 12 Measure G2 at BOA D It should be at least 300V Trace back to the G836 13 The last item operating improperly for no picture is the high voltage supply itself Generally all other measurements should be made before considering the high voltage since the majority of no picture conditions will not be caused by the high voltage supply Measuring the high voltage is extremely dangerous and not re commended Instead a quick method is to take a long screwdriver and ground the blade with two separate clip leads for safety Turn the 14 on for 5s and then SHUT IT OFF After it is off ground out the anode cap on the CRT with the GROUNDED screwdriver If done within 5s to 105 after power is turned off an arc should occur to the screwdriver indicating that the CRT was charged with high voltage If no arc occurs
73. hes are up the deflection on the screen will go up and to the right when the deflection signal on the BNC pins 7 and 10 becomes more negative with respect to the BNC pins 8 and no 11 Input signals larger than 2V may be used by attenuating with the gain controls and R1 and R2 on the X and Y deflection circuit boards However the potentiometers become much too sensitive for input signals greater than 10V peak to peak and R1 and R2 should be increased to provide pre attentuation for these larger input signals The input signals may be bipolar such as 45V or unipolar such as OV to 5 or to 5V The position potentiometer allows the deflection to be offset plus or minus half a screen thus a unipolar signal may be completely centered the screen Offsets more than half of _ the full scale inputs cannot be handled In other words if the full scale deflection is offset from OV by more than half its full scale value centering on the screen cannot be accomplished 3V peak to peak deflection signal for example may not be offset from 0 by more than 1 5 So 1 5V OV to 3V or OV to 3V are all acceptable but deflection input that goes from 1V to 4V cannot be used until it is shifted down a minimum of Table 2 2 summarizes the control settings for vari ous inputs The Z intensify input requirement is simply a TTL transistion from high to low This triggers the inten sity circuit to generate
74. ins a circuit that supplies 5V to the W682 If either the 20V or 20V goes to 0 in the case of a short circuit or blown secondary fuse the circuit supplying the 5V shuts down Because the 5838 has a low value resistor across the 5V 470 the 5V line pin A on the W682 is grounded This causes the base drive to Q1 to be shunted to ground through 016 and renders Q1 off 60V which shuts off the CRT CHAPTER 4 MAINTENANCE This chapter deals with the prevention diagnosis and repair of fault conditions Successful trouble shooting of the VR14 may be performed using a volt ohm milliampere meter however an oscilloscope facilitates and expedites isolation and repair of faults 4 1 PREVENTIVE MAINTENANCE preventive maintenance consists of ensuring that the equipment is getting and maintaining proper air flow for cooling and a periodic cursory inspection for abnormal hardware conditions Because of the power dissipation on the deflection and regulator heat sinks good air flow must be maintained A periodic check is required to see that fans are operating properly and are not obstructed either by dirt dust accumulation or inadvertently blocked by external equipment or surfaces Prolonged off screen deflection of the CRT beam can damage the VR14 Ensure that the X and Y driving signals into the VR14 never drive the CRT beam off screen because of intermittent incorrect signals 4 2 TROUBLESHOOTING troubleshootin
75. is plate Lift the assembly out to make room for removing the assembly cable connector The 15 connector is removed squeezing the retaining tabs on each side of the connector so that when the connector is pulled the tabs pass through square holes that they were butted against Do not pull the connector by its wires only by its plastic body To remove a faulty transistor unscrew the two 6 32 screws that hold the transistor down Then pull the transistor straight out from the socket Apply an even coat approximately 1 32 in thick of thermal compound to all mating surfaces of the new transistor Re place the new transistor making sure that the base and emitter pins are oriented properly otherwise the transistor case will not align with the two screw holes Also ensure that the insulating washer is between the transistor and the heat sink and each mounting screw has a star washer a Remove circuit boards and the four 6 32 screws holding the deflection heat sink to the rear panel b Remove heat sink assembly and its connectors if necessary and remove faulty power transistor Figure 4 2 Deflection Heat Sink Removal 4 3 2 7007165 Power Regulator Assembly Removal The 7007165 Power Regulator Assembly comprises G836 regulator printed circuit board with q mount ing frame for J1 2 J3 and To remove the 7007165 Power Regulator Assembly proceed as follows Procedure Remove the li
76. is tied through R12 to the CRT cathode Therefore in the absence of an intensify input the cathode resides 60V This along with the negative bias on the grid keep the CRT beam shut off When an intensify signal occurs gate C s output goes high allowing to receive base current from the 80 017 R11 R5 013 and D15 This drive turns on Q1 causing its collector and the cathode of the CRT to go from 60V to OV This turns the CRT beam on The duration of this intensify pulse is determined by the time constant of C2 R4 and is normally 300 ns 016 prevents the voltage supplied to R5 from exceeding 5V this is necessary to prevent damage to gate C When power is removed from the VR14 the CRT must be prevented from blooming and possibly burning the phosphor Blooming can occur because the necessary voltages that keep the CRT grid cathode 80 shut off drain to OV faster than the high voltage supply When the grid to cathode voltage becomes more positive than cutoff the CRT turns on very hard D8 and C14 prevent this from happen ing When power is turned off the goes to OV but in so doing C4 hangs on to its voltage and thus back biases D8 which does not allow C4 to discharge C4 momentarily acts like 1 5 power source allowing the collector and CRT cathode to hold at 60V which is the safe or off condition Eventually C4 discharges however by that time the high voltage has also discharged rende
77. l select information which comes from pin R This information either enables gate B to respond to the intensification spike or not Assuming B is enabled from pin R the positive spike causes the output of B to go toa low This low remains as long as the input spike to B is above its 1 or high threshold level As soon as the spike decays below the threshold B s output immediately reverts to the high state B s output is fed back to A s input 10 to allow A s output to latch high thus not requiring A s input pin 9 to remain low but rather be a momentary drop from a high Of course when the spike decays at B s input the latching input is removed from A pin 9 thus enabling A to respond to the next negative going transition on the Z intensify input D5 clamps the input from going negative during the negative going transition that occurs when A resets Gate C simply inverts the intensify pulse to drive the output pulse amplifier Gate C normally is low until a pulse comes along This low grounds out the base drive for Q1 therefore it will be off D13 and D15 guarantee that will be off even though there is a residual voltage drop across D and the output of gate QI s collector is tied through R7 and D8 to 80 With off the collector tries to ride up to 80 Vdc but D7 begins to conduct at 60 clamping the collector at 60V The 60V is generated by dropping the 80V across and zener diode 014 1 5 collector
78. nal ground The importance of using signal ground cannot be over stated most noise and washing displays are a result of indiscriminate grounding 2 7 The minimum voltage signal for full X deflection is 2V peak to peak and 1 7V for Y and R1 and R2 on the A225 are 3 3k see Figure 3 1 For larger input signals and R2 are normally 10k With the maximum input sensitivity is 0 5V The input impedance is 5k minimum for maximum sensitivity R1 and R2 3 3k and 20k minimum for and R2 10k When driving long cables more than 30 high speed deflection may not be possible unless the cables are terminated in a low imped ance less than 1000 since the VR14 input impedance is too high for this application easy way to attain high speed deflection is to use the 24 pin rear connector for the input signals and place the terminator across the BNC connectors since they are in parallel with the input Needless to say if terminated lines are used the X and Y driving source must be of low enough impedance to tolerate the additional load The deflection amplifiers can be operated as inverting or noninverting by selecting either or each polarity switch at the rear panel If the polarity switches are down the deflection on the screen will go up and to the right when the deflection signal on the pins no 7 and no 10 goes more positive with respect to the BINC pins no 8 and no 11 If the polarity switc
79. nd Y A225s with one another to see if the problem changes axis Continued on next page d Weak brightness but proper operation generally indicates C5 has shorted on the W682 board This occurs due to a rare but possible internal arc within the CRT e Ifa weak picture that is deflected off the screen on all sides is encountered with excessive and ripple the high voltage supply should be replaced 4 3 ASSEMBLY REPLACEMENT INSTRUCTIONS Other than the G838 A225 s and W682 circuit modules most repair and replacement will involve the G836 regulator subassembly the regulator heat sink assembly and the deflection heat sink assembly and in rare cases the high voltage assembly yoke and CRT It cannot be stressed too strongly that the VR14 line cord be removed from the line before doing any maintenance Turning power off or removing fuses does not render the unit safe from shock hazards since the power switch and fuse interrupt only one side of the ac input line voltage the other side is permanently connected as long as the line cord is plugged in Do not take chances unplug the line cord 4 3 1 Deflection Heat Sink Removal see Figure 4 2 To remove the deflection heat sink proceed as follows Step Procedure Remove the line cord and all circuit modules above the deflection heat sink assembly G838 A225 A225 W682 Remove the four 6 32 screws that hold the heat sink assembly to the rear chass
80. ne cord and all circuit modules G838 A225 W682 Remove all four cable connectors Figure 4 3 coming into the nector bracket on the 7007165 by squeezing the two locking tabs on the sides of each connector while pulling the connector straight up allowing the locking tabs to pass through the square holes they were butted against Do not pull the connector by its wires only pull it by its plastic body Remove the two mounting screws for the 7007165 from the opposite side of the 7007165 chassis wall The 7007165 is now free and may be pulled straight out NOTE When placing the 7007165 back into the unit ensure that the bottom of the circuit board rests in the slotted groove insulator block provided on the bottom chassis For troubleshooting the 7007165 may be operated outside its normal mounted position by laying the board flat and reconnecting the four cable connectors Ensure that the etch side of the module does not touch the chassis causing short circuits by insulating the board with a book or piece of cardboard as shown in Figure 4 4b NOTE The 7007165 has 80 80 and 400 available Use extreme caution when trouble shooting the board Also these voltages do not disappear immediately when power is shut off 4 3 3 Regulator Heat Sink Removal Figure 4 5 To remove the regulator heat sink proceed as follows Step 2 Procedure Remove the 7007165 See Paragraph 4 3 2 for in
81. ng out the circuit against the chassis when trouble shooting the board outside the unit Figure 4 4 7007165 Removal 4 10 4 1 i a JUST E 4 Remove 7007165 shown in Figure 4 4 and unscrew the four 6 32 heat sink mount ing screws from the side chassis Remove two pin connector from high voltage bracket b Lift heat sink straight out and repair faulty transistor Figure 4 5 Regulator Heat Sink Removal NOTE Thermal cutouts have 115 Vac on them be sure line cord is removed 4 11 Step Procedure Using 1 4 nut driver loosen the screw that holds the yoke neck clamp by inserting the nut driver through the access slot provided in the CRT shield Loosen sufficiently for the yoke clamp to be slipped off the yoke Carefully remove the CRT socket connector and slide the yoke clamp off the CRT neck Slip the yoke connector through the access slot in the CRT shield and pass it along with the entire yoke assembly off the CRT neck and out the rear Sometimes the yoke gets stuck at the socket end of the CRT because the yoke plastic mounting piece hugs the CRT neck tightly and must be spread to pass over the CRT socket To remove the CRT proceed as follows Step Procedure Remove the yoke first as described above and double check that the line cord is removed With a long bladed screwdriver that is grounded to the chassis a clip l
82. ntical however because the CRT is a 3 x 4 rec tangle only 3 4 the horizontal deflection is required for full vertical The deflection inputs are differential but may be driven from single ended sources When using single ended sources the differential input is helpful in eliminating annoying ground loops and hum etc By carrying the local common or ground along with the deflection signal from where it is generated a quasi differential signal is generated Instead of terminating this ground at the VR14 chassis use the ground as if it were one side of a differential signal the other side being the deflection signal itself The VR14 will use the deflection signal with respect to its own ground and not the VR14 ground which most likely will be different causing picture ripple and hum If a separate ground 15 not available the single deflection signal is applied to one side of the differential input the remaining differential input i terminated with the source impedance of the driving signal or if this is low the input is simply grounded signal ground not chassis ground Signal ground is the shell of the BNC connectors that are isolated from the chassis or pin no 9 and pin no 12 that are X and Y signal ground res pectively Never use chassis ground for X and Y input reference always use signal ground When using balanced or differential inputs tie each side of the twisted pair shielded cable to the two inputs and the shield to the sig
83. on fault is on the boards themselves assuming of course proper input signals are applied and all power supply voltages are nominal If the yoke current goes full negative only when the A225 card 15 plugged into that axis the most likely suspect is the 2N2904A Q2 If one axis is faulty a quick check can be made by swapping the and Y deflection boards A225 to see if the faulty axis follows the circuit board in question B 1 APPENDIX A225 REPAIR After the power supply and deflection power transistors have been proven sound incorrect deflection coil current readings may be isolated to the A225 circuit board itself If when the A225 is plugged in the deflection current goes full negative about 4V as measured at A02 A for X A03 A for Y and not controllable Q2 has probably opened and should be replaced If only half deflection is working no positive current or no negative current capability and the power transistors are operating properly Q3 should be replaced for no positive current and Q4 for no negative current Also check R26 and R27 for burns These resistors overheat if the deflection amplifier is operated in the fault current limit condition for any length of time Finally if C9 or become shorted R9 or R10 respectively will burn out Check C9 or C10 with an ohmmeter to verify this type of failure
84. out written permission o ul lt xxi TIN Z G gt N 92 x VRIA4 OOOQ0 S9 DEC FORM NO 4 DRC 100 m ge FAULT PROT s TN MK sn Be o Rn Pagi Apr eid M OCTET CANE V ETT Qn d aasawa A sa s rs wr o G84O LIGHT PEN OPTION W684 8 LEVEL INTENSITY OPTION j NOTES I MODULE INFORMATION SHOWN FROM WIRING SIDE SEE STANDARD ON FIR 2 EQUIPMENT CORPORATION MAYNARD MASSACHUSETTS UNLESS OTHERWISE SPECIFIED _ UNLESS OTHERWISE SPECIFIED DIMENSION IN INCHES LERANCES DECIMALS FRACTIONS D U FINAL SURFACE QUALITY Y REMOVE BURRS AND BREAK SHARP CORNERS MATERIAL UTIL AAT ION Wir cH V R 4 ICMU VRIA4 3 NUMBER r NN s E vRIA4 0 3 FINISH anm EI 2 1 5 39 8 7 This drawing and specifications herein are the prop of Digital Equipment Corporation and shall not be reproduced or copied or used in whole or in part as the basis for the manufacture or sale of items without written permission REF E IO 4 O o1 REF 3 155 12 A REVISIONS CHANGE NO VRI4 OOO0I9 gt A FISHMAN gir E val x gt
85. ows This current does not flow into pin of E2 because if it did pin 10 would rise in volt age because the input of E2 looks like a high impedance The current must flow through R10 and R33 The only way for this to happen is if the feedback voltage is a negative value because R10 R33 is tied to pin 10 which is OV so pin must be negative In fact if 1 mA flows through R10 and R33 the feedback voltage must 3 2V and negative The 3 2V originates from the 0 50 resistor in series with the yoke therefore 3 2V divided by 0 50 current is flowing through the yoke This of course is 6 4 which is an excessive amount of voltage and current limit circuits explained later would probably be called into action to limit the output transistors The remaining transistors on the A225 boost the current from E2 to a sufficient drive level to operate the power transistors on the large heat sink The output of E2 drives through its base resistor R14 serves two purposes a stage of inversion and a level shifter Inversion is necessary to get the final output in the proper polarity for negative feedback Level shifting is required to drive Q2 at its base voltage E2 cannot do this alone The stage has no voltage gain but has current gain Q2 however has voltage and current gain and is where the true output voltage is first generated Q2 is a grounded emitter amplifier where in this case the emitter although tied to 20 can
86. percent point of the negative input transition to the 50 percent point of the output pulse is less than 100 ns Driver must sink 4 mA Z Direct positive going pulse not exceeding 65V but at least 45V in height and not exceeding 10 us but at least 1 ps in duration will unblank the CRT to a viewable intensity This signal is ac coupled to the CRT grid Channel Select With the Channel Select Switch in the Channel 1 position a positive level of greater than 2 4V but not exceeding 8V will enable the Z input circuit A level of less than 0 8V but not more negative than 4V will disable the circuit With the switch in the channel 2 position a positive level will dis able the Z circuits a negative level will enable it Placing the switch in the channel 1 and 2 position disables this input All power supplies necessary for operation of the unit are self contained Input Requirements Voltage 100V 10 115 1096 230 1096 Selectable by tap changes Frequency 50 60 Hz Power lt 500W Current Single Phase 1 3 BLOCK DIAGRAM DESCRIPTION Figure 1 1 is the functional block diagram of the 4 The X and Y position signals are connected to their respective A225 deflection amplifier circuit boards through polarity reversal switches The A225s boost the input signal to a level sufficient to drive the power transistors while also providing gain and position controls In turn the pow
87. rack mounted unit to the area immediately above the unit The table top model has a solid top cover The cooling air exits from the rear of the unit Therefore at least 2 in of free space must be provided immediately behind the unit Do not push the 4 flush against a wall or solid vertical surface that would cut off air circulation NOTE Before applying power to the VR14 ensure that the polarity switches on the rear panel and the position potentiometers are set for the particular input signals being used Because of the universal nature of allowable input signals the de flection amplifiers may be driven into saturation far off screen by a wrong combination of polarity and position settings Leaving the deflection amplifiers saturated way off screen continuously may cause damage See Paragraph 2 5 and Table 2 2 for proper settings 115 TB1 TB2 jumper jumper 230 Vac TB1 2 100 1 2 Interchange Interchange Orange with White with Red from Gray from Transformer Transformer Figure 2 1 Input Power Jumper 2 2 2 2 FRONT PANEL CONTROLS The on off brightness control and the channel select control switches are located on the front panel The on off switch turns on input power to the VR14 when the knob is rotated clockwise from the maxi mum counter clockwise off position Turning the knob clockwise also increases the brightness of the displayed informa
88. re identical therefore only one axis will be described The de flection circuit consists of the A225 circuit board two power transistors and a deflection yoke see Figure 3 1 The input signal after going through a polarity reversal switch is applied to pins E and B on the A225 circuit board The input signal is handled as a differential or balanced signal even if the input is driven from a single ended source the single ended source being a special case of a balanced input where one side is grounded and R2 establish the minimum input impedance and form an attentuator with R3 the gain potentiometer The voltage developed across R3 is amplified and converted from balanced to single ended by amplifier ET El is an inverting amplifier whose gain is established by the resistor ratios of R7 to R4 and R to R5 The bandwidth of the amplifier is tailored by C5 and C6 which act internally on the integrated circuit and C13 and C14 which act at high frequency to roll off the low frequency gain established the R7 to and R to R5 ratios 6 is generated for both and E2 from the 20V This is done by dropping resistors R18 and R19 and zener diodes D5 and D and and C2 and are local high frequency bypass filters for the 56V to reduce any high frequency signal noise at each operational amplifier thus avoiding the possibility of parasitic oscilla tion The single ended output of is connected to R4 which i
89. red from the time new X and Y position information is presented to the VR14 and the intensify pulse is requested depends upon how large a position change is requested and how perfectly settled the dot has to be to its final ideal position Full scale de flection changes such as far left to far right or corner to corner require 20 15 waiting period for the dot to settle to within 0 01 in of its final value 1f larger errors can be tolerated 18 us may be used Small deflection changes require much less time A 0 1 in change can be settled in less than 1 us If there is no way for the circuits driving the VR14 to distinguish small position changes from large ones each change must be assumed to be large and thus requires the worst case delay Also if the D A converters driving the display have gliches error spikes generated while chang ing values proportionately longer delays are required since the deflection amplifiers will have to recover from the gliches The Z direct allows direct modulation of the brightness Positive going signals increase brightness This input is not direct coupled therefore dc brightness information cannot be used The RC time constant is approximately 30 ms The Z direct may be used with or without the Z intensify input If Z direct is used with Z intensify it can alter the brightness of the normal Intensify pulse by adding Bi subtracting at the CRT grid This is accomplished by pulsing the Z direct with a puls
90. rent Return the position potentiometer to its original position If the voltage at A02 A is beyond 2 2V shut down immediately cause the position potentiometer on the A225 can drive more current than the 2 2V limit it is possible that it the position potentiometer has been adjusted to one extreme or the other To prove whether this is the case or if the A225 circuit board is faulty turn the position potentiometer as follows clockwise if the voltage at A02 A was very negative counter clockwise if the voltage at A02 A was very positive If no change is noted at A02 A after adjusting the position potentiometer the A225 board is faulty and should be replaced or repaired refer to Appendix C Repeat the same tests as in Step 7 for the Y axis deflection circuit A225 plugged into A03 Monitor A03 A Refer to Appendix C for A225 repair If the fault has not been isolated the intensity circuit W682 the electrode voltages and the high voltage supply are suspect The output of the W682 drives the cathode At rest it should be 60V and when triggered to approximately OV Apply a proper input to the W682 3V to OV transi tions and check to see that the signal reaches A04 J If so check 04 with the channel select in the 1 and 2 position to see that a high is present there If so see that 5V is being supplied to A04 A If A04 A is less than 4V replace or repair the 5838 module as this is where the 45V is developed If t
91. replace the high voltage supply 4 2 2 Faulty Picture a No Focus Check the range of the focus potentiometer on the G838 by monitoring the focus voltage at BO4 J while adjusting the focus potentiometer through its range Minimum range is 350 to 60 See G836 for repair Half or Quarter of the Picture Missing Generally this condition represents the fact that one of the two deflection transistors is not working thus only half deflection is available The transistor in question can be identified by observing which side of the screen is not working The left and bottom portions of the screen are controlled by the PNP 2N4399 power transistors on the deflection heat sink These are the lower two transistors the left side of the screen is controlled by the left lower power transistor if the deflection heat sink is viewed from the front of the VR14 the lower part of the screen is controlled by the right lower power transistor Of course the upper and right are controlled by the NPN 2N5302 the right side of the heat sink controlling the upper screen the left side of the heat sink controlling the right screen The remaining possible faulty picture patterns such as picture swim 60 Hz oscillations distortion etc will be restricted generally to improper input signals especially grounding techniques or faults on the A225 circuit board If input signals are not suspect a faulty A225 may be isolated by swapping X a
92. ring the CRT safe Five volts are supplied at pin A for and also as a clamp for 016 logical one level is gener ated across D9 10 11 and 12 through R2 D2 and D3 protect gate and gate D inputs from exceeding 5V DI and D4 prevent the same inputs from becoming negative The two remaining inputs the W682 are the Z select and Z direct The Z select is a bit that allows the intensity pulse to be multiplexed or time enabled As mentioned before whether or not the inten sity pulse is allowed to pass to the output through gate B depends whether or not a high input is _ available at pin 13 of gate B This high is continuously available independent of Z select input when the channel select switch is in the 1 amp 2 position When the channel select switch is in the 1 position intensification occurs only when a high is presented at Z select and intensify input is presented When the channel select switch is in the 2 position gate B is enabled only when the Z select input is a low The Z direct is an input directly to the grid through C5 Video or other time varying brightness information may be coupled to the grid at pin D UNLESS OTHERWISE INDICATED RESISTORS 1 4 W 5 DIODES IN 4004 12 0294 Figure 3 4 Circuit Diagram C838 In the event of a failure of either the 20V supplies deflection ceases and a bright spot occurs on the CRT causing burn To prevent this G838 see Figure 3 4 conta
93. s the input to the actual deflection amplifier El serves more as a signal conditioner preamplifier The amplifier is essentially an inverting voltage to current amplifier that is an input voltage is con verted to an output current 180 out of phase or inverted with respect to this input Because the input is a voltage however the output current must be converted back into a voltage in order that the feedback compare volts with volts Current is converted to voltage with a 0 50 resistor in series with the yoke The voltage across this resistor is an exact replica of the current flowing in the yoke thus the amplifier compares the input voltage with the yoke current to ensure that the yoke current is an exact replica of the input position signal E2 compares the input voltage at R4 with the feedback voltage at R33 RIO 3 1 R31 R10 R20 A 2 2K IK 10 R30 RETURN p 270 R25 O 47 4 2 02 1 4W 5 16 03 2N4923 100 R26 4 2 RI E 10K Q1 54 R3 DEC2219 dd ddr K INPUT SIGNAL C11 R22 R15 220pF 680 P R2 1 15 316 10K 1 8W 1 1 8W 1 R28 10 1 2W PWR GND L 06 C10 IN753A 22 6 2V 20 SIGNAL H GND 22V 7007082 0 1 5W 56 234399 235302 0 1 22 V UNLESS OTHERWISE INDICATED ALL CAPACITORS ARE 100V 5 ALL DIODES ARE D664 JUMPERS FOR THE A 2
94. s the null For example if the input line voltage increases causing the raw 20V to increase the 20V regulated output starts to climb The null would then be disturbed and would shut the out put down somewhat so that the null could be maintained On the other hand if a heavy load occurred on the 20V regulator causing the 20V to drop the null would again be disturbed and would act in a way that would turn on the output hard enough to return to its proper level the level that main tains the null This regulating action takes place in a matter of microseconds The actual output voltage at which the null will be maintained is determined by the ratio of R3 to R2 times the reference voltage The mechanics of how controls the output can be traced stage by stage drives an emitter follower Q1 to give the output of El sufficient drive capability to fully turn on Q2 if required Q2 through R12 controls the base current of the series pass transistors that are external to the G836 board The pass transistors maintain a constant output since they are supplied power from the raw dc source cause of the high open loop voltage gain high frequency networks are used to roll off the gain of the regulator to ensure stable nonoscillatory operation C2 R5 and C5 serve this purpose The actual point where the output voltage is regulated is determined by where the sense leads are tied The sense leads are nothing more than the feedb
95. so in this case if the two 134001 diodes used as current limiting for the power transistors are shorted the power transistors cannot receive base current and thus will not turn on rendering their output OV To check for this condition turn off the power and measure resistance with a VOM set at RX1 across D15 and D16 if the 20V was 0 and D13 and D14 if the 20V was 0 The resistance with the VOM lead connected either way should always be above 50 APPENDIX DEFLECTION AMPLIFIER TROUBLESHOOTING When the deflection circuit cards A225 are removed their respective power transistors receive no drive and therefore are off When monitoring A02 A X yoke current sample and A03 A Y yoke current sample no reading should be observed Any voltage at these points indicates a power transistor is on by itself Generally this transistor is shorted To determine which transistor is faulty observe which pin 02 or A03 A has voltage The 02 X axis transistors are on the right side of the heat sink assembly when viewed from the front of the VR14 A03 A Y axis transistors are on the left side In both cases a plus voltage at 02 or 03 means PNP 234399 is at fault This is the lower transistors on both 1458 If the voltage at A02 A A03 A is minus the NPN 2N5302 are faulty These are the upper transistors on both sides If no readings are observed at A02 A or A03 A when the A225 boards are moved then the deflecti
96. structions Remove the four heat sink mounting screws on the right chassis wall when viewed from front 4 8 TO VR14 6836 REGULATOR SUPPLY HEAT SINK TO TO DIODES TRANSFORMER AND FILTERS 12 0331 Figure 4 3 7007165 Power Regulator Assembly Step Procedure 3 Lift the heat sink assembly straight out 4 To remove a faulty transistor s unscrew the two 6 32 screws holding the transistor s down then pull the transistor s straight out from the socket Apply an even coat approximately 1 32 in thick of thermal compound to all mating surfaces of the new transistor Replace the new transistor ensuring that the base and emitter pins are oriented properly otherwise the transistor case will not align with the two screw holes Also ensure that the insulating washer is between the transistor and the heat sink and that each mounting screw has a star washer 4 3 4 Yoke Removal To remove the yoke proceed as follows Step Procedure Remove the line card and all the circuit modules C838 A225 W682 along with the plastic CRT socket cover 2 Carefully remove the yoke cable connector from its mating connector on the inner side of the circuit card mounting bracket 4 9 Remove power cord and all connectors to the 7007165 Unscrew mounting screws from the opposite side of the vertical chassis wall Reconnect connectors and place a cardboard under the 7007165 to prevent shorti
97. tensity pulse to be time multiplexed between two input sources The G838 fault protection board disables the intensity circuit in the event of a 20V failure This prevents the phosphor screen from burning as there would be deflection under these conditions Line power is passed through a fuse an on off switch and then through two normally closed thermal cutout switches The switches are located on the 20 regulator heat sink and the X deflection heat sink and in the event of a fan failure or excessive temperature on either heat sink VR14 input power will be shut off until they cool down The line power is then connected to the power transformer the high voltage power supply and the fans The high voltage supply converts the input line voltage to 11 5 kV that is connected to the CRT anode The power transformer has three basic secondaries a 6 3V for filament a 35 130 for CRT electrodes and a 58V center tapped for deflection The 58 Vac is rectified and filtered to provide 35 Vdc unregulated This 35 Vdc is regulated with circuits on the G836 board along with four power transistors on the regulator heat sink assembly The regulated output is 20 Vdc and is distributed to the deflection amplifiers The 35 130 ac is rectified and filtered on the G836 to generate 80 and 400 The 80 is used for the brightness potentiometer which is tied to the grid side of the brightness control is connected to another
98. the opposite side s region In so doing the positive would not shut off for example until the negative transistors were well turned on Thus the amplifier would have control to cancel any nonlinearities that might occur This task is accomplished with R23 R26 R27 The major influence is R23 because it places voltage between Q3 and bases which allow one to be on a little into the conduction region of the other If R23 were 0 the dead zone would be very abrupt causing maximum distortion On the other hand as R23 is increased the transistor conducts further and further into the opposite side s operating region This creates two major problems The power dissipation causes excessive heating of the output stage and the extra current required overloads the power supply The value of R23 is chosen therefore to minimize dissipation but also to minimize the cross over distortion The output at the yoke has the capability of swinging full 20 This is necessary because even though the yoke is less than 0 10 at dc it has inductance thus to force current through at high speeds requires a lot of voltage V L change 2A through 20 pH 2 ys requires 20V That is why the A225 not only has to boost the input signal to a large current but also has to have good voltage capability to force the yoke current to change quickly 3 6 Position control in the A225 is accomplished by adding another input to E2 exa
99. tion A delay of about 30s occurs before information appears on the screen while the CRT filament warms up In an operating system it is recommended that power be left on the display even when it is not in continuous use so that the filament warmup delays do not occur The channel select switch works in conjunction with the channel select signal applied at the rear connector When not using the dual channel feature the select switch should be in the 1 and 2 posi tion When using the dual channel system points on the screen will be intensified from Z intensity inputs only when the channel select signal at the rear connector is high and the channel select switch is in the channel 1 position If the channel select input signal goes low while the select switch is at 1 intensification ceases On the other hand the channel 2 position works in the opposite manner If the channel select input signal is low and the select switch is at 2 Z intensification signals will intensify on the screen Thus if a group of information points is to be separated from another group separation can be achieved by having group 1 intensification pulses occur only when Z select line is high and group 2 intensification pulses occur only when the Z select line is low Channel select position 1 amp 2 overrides the select input signal and displays every intensification pulse of both chan nels at once To observe only channel 1 information select channel 1 and all channel 2 poin
100. ts are locked out By selecting channel 2 only channel 2 points are displayed 2 3 REAR PANEL CONTROLS AND CONNECTORS The rear panel see Figure 2 2 has two slide switches seven BINC connectors and an Amphenol 24 contact Blue Ribbon DEC type connector The mate is DEC No 12 03466 Amphenol No 57 30240 Table 2 1 lists rear connector pin assignments The two slide switches allow the polarity of the X and Y input signals to be selected as to their re sponse on the CRT screen Physically all the switches do is interchange the with the X connections and the with the Y connections With the polarity switches in the position the CRT beam when viewed from the front will go up and to the right if the Y and X input signal voltage becomes more positive with the polarity switches in the position the beam goes up and to the right when the input signals become negative The input reference is always the BNC referred to the BNC pin 7 with respect to pin 8 for X pin 10 with respect to pin 11 for Y Pin 2 Pin No 3 Pin No 4 NOTE When unipolar inputs are used to 2V or to 6V representing the full screen the polarity switches must not be reversed from their originally setup position If the input is OV to 2V and the switches are in the position switching to the position will drive the de flection amplifiers into current limit because instead of offsetting th
101. ule Utilization List Module Utilization Chart Wired Assy 4 Wired Assy VR14 G836 Power Regulator Board Assy G836 Power Regulator Board Assy VR14 Power Supply and Regulator Bd 5836 P S Heat Sink Assy VR14 P S Heat Sink Assy Circuit Schematic Heat Sink Deflection Heat Sink Assy Deflection Heat Sink Assy Circuit Schematic Deflection Power Supply Assy VR14 Power Supply Assy VR14 Circuit Schematic Pwr Sup 5 1 5 3 5 7 5 15 5 23 5 27 5 33 5 37 5 39 5 41 5 43 5 47 5 49 5 55 5 57 5 59 5 61 5 63 5 65 5 67 5 69 5 73 5 79 Sheets 2 4 4 2 3 2 1 1 1 2 1 3 1 1 1 1 1 1 1 2 3 2 lt MASTER DRAWING LIST UNIT VARIATIONS MAINTENANCE Eg Ps MANUALS r4 H m P PEN NN ERR USED ON OPTIONS LEIA EQUIPMENT 4 t A 4 2 f i K p ui biu t s M h S jw Mos ve d 5 d M MAYNARD MASSACHUSETTS VRl4 DISPLAY 7 ENG TOATE ISH R AT N ps ss DIST 131 Dec 16 325 1048 N471 REVISIONS A PL G836 0 0 POWER SUPPLY amp REGULATOR ASSY PL POWER SUPPLY HEAT SINK ASSY POWER SUPPLY HEAT NK ASSY PL RE
102. urrent from its emitter this very current must flow into Q3 s collector from the base of the 2N4399 which will now turn Be cause the 2N4399 s collector is also tied to the output the yoke it also supports the output current and in fact becomes the primary source of output current Depending on Q3 s demands the 2N4399 0 is completely slaved to Q3 If turns on harder so does the 2N4399 If shuts off so does the 2N4399 Therefore the output looks like it is an emitter follower Q3 but the 2N4399 delivers all the current and handles the necessary power dissipation requirement To minimize power consumption the output would like to operate in Class B that is while positive current is required no negative current transistors should be turned on and vice versa However this approach creates problems at the point where the transition between positive and negative current takes place The reason is that one set of transistors does not shut off exactly where the other set takes over but instead shut off prematurely This creates a dead zone or no man s land where neither the positive nor the negative transistors are on and controllable The appearance on the CRT screen of such a phenomenon is a bunching or nonlinear compression of displayed information where it occurs usually near the center of the screen This problem can be solved by not allowing the positive transistors to shut off at zero but rather conduct somewhat into

laboratory data products VR14 CRT display user`s manual

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