Service Manual for LK2 Series of Power Amps
Contents
1. 7096 of LK2 faults Important Information about this modification Please read through this procedure in its entirety before starting any work It is important to follow ALL instructions carefully and exactly This procedure involves soldering and de soldering and it is advised that only personnel with a fairly high degree of soldering skill undertake this task Due to the age and the years of heat stress some of the solder joints may have changed their chemical properties and if this is the case it will be quite difficult to melt them Use flux or melt new solder onto the old solder joint Use heat and patience not force The changes outlined in this procedure will protect the LK2 from similar potential failures in the future by using higher wattage resistors than were originally used and adjusting the position of some components to minimise heat damage It is advised that all these modifications are carried out to both channels Estimated time for completion of this task hour CAUTION Important Safety Information Residual Voltage With certain faults especially but also under normal circumstances there can be residual voltage stored in the boards which could cause quite a serious electric shock To avoid this it is best to leave the LK2 switched off for a few hours before starting work on it and then using a voltmeter measure across the metal contacts of each of the big capacitors DO NOT TOUCH on each channel DC voltage2. Enid T3 C13 C14 Exc S 4 v w i NEXT HIGHER ASSY 08 28 44 8 Oct 33 FIRM NAME PCAS 2 L1R SIZE FSCM NO D ae PCAS 28 DWG NO
3. rrrrr OTC TAG THOMSON 33UF 10 10 63V PEST TH PCO200 C N rrrrr STC TAG THOMSON 100NF 103 3 10 63V PEST TH C0200 C N Y rrvrvrvvreey 100UF 20 20 63V ELTR TH C N Y PCOZUDY 7443 4 ECC RUBYCON 100UF 20 20 63V ELTR TH C N X PCO200 77711111 ECC RUBYCON 22UF 50 20 50V ELTR TH PCO100 C N Y Pack gg NCC RUBYCON MULLARD 22UF 50 20 50V ELTR TH PCO100 C N X crrrrr NCC RUBYCON 7 MULLARD 6U8F 10 10 63V ELITR TH PCO100 C N Y 7 ATA AA AA 6U8F 10 10 63V ELTR TH PCO100 C N Y AAA ATA AA AA 10000UF 20 20 64V ELTR TH C N X PCO400 EE BHC cr 10000UF 20 20 64V ELTR TH G N Y PCO400 BHC AT OPE AA Sy Frrrvrirett 220PF 2 rrvrvvevsrye ve 2 160V PST TH C0900 2 160V PST TH C0100 Q Z F Q Z F Copyright O 2000 Linn Products Limited All rights reserved MATERIALS OBSOLETE PART PBOM PRINT BILL Assembly Number PCAS 003 Units Ouantity Units T C Des Part Number 1 00000 ONES R C020 CAP 033 1 00000 ONES R C021 CAP 250 1 00000 ONES R C022 CAP 020 xx Warning Part OBSOLETE on 29 OCT 1999 1 00000 ONES R C023 CAP 020 xx Warning Part OBSOLETE on 29 OCT 1999 1 00000 ONES R D001 MISS 009 Warning Part OBSOLETE on 29 MAR 1990 1 00000 ONES R D002 MISS 001 1 00000 ONES R D003 MISS 001 1 00000 ONES R D004 MISS 001 1 00000 ONES R D005 MISS 009 Warni
4. The LK2 series had a trip circuit for each channel which was designed to protect the LK2 board and or speakers from a potentially damaging over current situation This means that if the LK2 senses that it is drawing too much current it shuts down the affected channel This situation may be caused by a faulty speaker internal short circuit soeaker cables shorted together very loud music faulty pre amp etc How to clear trip Once a channel trips it will remain in trip mode until the LK2 is switched off for up to 20 minutes It is best to ensure that you leave the unit switched off for the full 20 minutes if you power it up before it has fully discharged un tripped the trip capacitors will charge up again and you will have to wait another full 20 minutes We have heard of customers who do not leave it switched off for long enough switching it on before it is ready and perhaps doing this a few times then think the product has a permanent fault Continuous or repeated tripping It is important to remember that the trip circuitry is included as protection and the LK2 may be tripping for a very good reason If tripping occurs continuously or even occasionally it may be because the LK2 is doing its job correctly and something within the system is causing it to trip The source of the problem needs to be isolated and removed perhaps the speaker or the speaker cable the pre amp is faulty etc See Introduction to Fault Finding fo
5. 4 Disconnect both transformer connectors the cables going from transformer to board from the board 9 Lift the LK2 up so that it is standing on one of the heatsinks Each channel is held into the tray by 2 countersunk screws that attach to the heatsink on the underside Hold the channel that is now uppermost to prevent it from falling once it has been freed and remove the two screws from this channel only Lie the LK2 down correct way up and remove the channel that you have just loosened this can sometimes be tricky so follow these instructions e Pull the board slightly toward the front of the unit until the 3 pin cannon input socket at the rear is clear of the back panel it may sometimes be necessary to push the back panel slightly in the opposite direction until the socket is completely clear e Lift the end of the board containing the 3 pin cannon socket upwards see picture until that end of the board is clear of the tray Some delicate manoeuvring may be necessary but dont force it 2 Move the entire board in this direction ES i ml e By carefully moving the board backwards amp upwards it should now be possible to lift it up and out of the tray e Repeat the above instruction for the other channel Step 2 Page5 eA Copyright O 2000 Linn Products Limited All rights reserved Contents Paul O Neill LK2 Service Manual Step 2 Remove the heatsinks from the boards if required 1 Using the 5 5mm spa
6. Number PCAS 003 POWER AMPLIFIER PCB ASSEMBLY OBSOLETE PARI Units ONES BOM Type C Quantity Units T C Des Part Number Description 1 00000 ONES R CO0l CAP 035 Am an Warning Part OBSOLETE on 09 JAN 1995 1 00000 ONES R C002 CAP 034 1 00000 ONES R C003 CAP 003 1 00000 ONES R C004 CAP 003 1 00000 ONES R C005 CAP 099 Warning Part OBSOLETE on 27 APR 1989 1 00000 ONES R C006 CAP 039 1 00000 ONES R C007 NO INEO NO LINN PART NUMBER EXISTS FOR THIS PART 1 00000 ONES R C008 NO INFO NO LINN PART NUMBER EXISTS FOR THIS PART 1 00000 R C009 ONES CAP 068 1 00000 ONES R C010 CAP 020 VUE Warning c Part OBSOLETE on 29 0CT 1999 1 00000 ONES R C011 CAP 020 xx Warning Part OBSOLETE on 29 OCT 1999 1 00000 ONES R C012 CAP 003 1 00000 ONES R C013 CAP 003 1 00000 ONES R C014 CAP 022 1 00000 ONES R C015 CAP 022 1 00000 ONES R C016 CAP 085 1 00000 ONES R C017 CAP 085 1 00000 ONES R C018 CAP 037 Warning Part OBSOLETE on 28 MAR 1990 1 00000 ONES R C019 CAP 038 Frrrvrvve br 63V PST TH CO400 3554 N Y 100UF 20 20 10V TANT TH C N Y PCOZ007 711111 STC TAG THOMSON 22UF 50 20 50V ELTR TH PCO100 C N Y rrr rr NCC RUBYCON e MULLARD 22UF 50 20 50V ELTR TH PCO LOG C N b pydg wg NCC RUBYCON MULLARD 1NF 10 10 63V CERA SM CC0805 C N Y Frrrrvrrt v 68PF 2 rrvrvrveys 29 160V PST TH COTIO0 N Y 33UF 20 20 10V TANT TH PCO200 C N b
7. Q24 amp Q34 2503519 NPN 160V 15A MT100 Linn part no TRAN 018 Check replace power transistor s Part details Q20 amp Q27 28A1386 PNP 160V 15A TO218 Linn part no TRAN 017 Q24 amp Q31 2503519 NPN 160V 15A MT100 Linn part no TRAN 018 Check replace power transistor s Parts may be as listed in the box above or they may be as listed below depending on whether it is an earlier or later version of LK260 Part details Q20 amp Q27 TIP36C PNP 100V 25A TO218 Linn part no TRAN 005 Q24 amp Q31 TIP35C NPN 160V 15A TO218 Linn part no TRAN 004 See Fault Finding on the LK2 hints amp tips section at the beginning of this manual Distortion crackling etc E BN Possible Cause s Output distorted may one or both channels Page16 Contents May be intermittent Power up problem if amp receives insufficient power it will struggle to amplify the signal and distortion will occur See Power up problems section above Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Service Manual Output very badly Applies only to distorted LK260 amp LK275 One of the Reliability Modification components has failed Probably constant Distorted output May be intermittent Faulty component in circuit Crackling noise Probably Transistor in circuit faulty from output intermittent may
8. RATING USE MINIMUM 2 5W PART 1 00000 ONES R R050 RES 078 4K3 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R051 RES 063 15R19 ME 1 4W 0425W 200V5 50pprqmiy 4 4 C N Y ava Copyright 2000 Linn Products Limited All rights reserved PBOM Assembly Number Ouantity 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 ONES ONES ONES ONES ONES ONES ONES PRINT R PCAS 003 R053 R055 R056 R057 R059 UOOL U002 BILL Part Number RES RES RES RES RES RES O F MATERIALS 15 AUG 00 Page 8 POWER AMPLIFIER PCB ASSEMBLY OBSOLETE PART Units 048 009 009 048 009 018 IC 005 IC 006 ONES Description BOM Type C Type Kit Cost L2R IS ME 1 4W 0 25W 200V 50ppm N Y 27 Ry Loy ME LAW 0s 25W 200V D pplu ya y N E 2 R TS ME 1 4W 0 25W 200V 50ppm N Y LI2R LI9 ME 1 4W 0 25W 200V 50ppm amp N X 27R 1 MF 1 4W 0 25W 200V 50ppm C N Y 15K 15 MF 1 4W 0 25W 200V 50ppm C N Y LM317T VOLTAGE REGULATOR TO220 C N Y 317T NATSEM LM337T VOLTAGE REGULATOR TO220 C N Y 337T NATSEM THOM ve Copyright O 2000 Linn Products Limited All rights reserved P2 P1 P2 P1 RIGHT LEFT R Re av UP TO RSI UPTO Cea UP TO D12 UP TO 037 UP TO PS MISSING REFS NONE R37 UNREG SENSE 1 d 4 AD c9 C18 Cit Ed
9. T0126 140 MOTOR ZTX653 NPN 100V 2A ELINE 653 ZETEX ZTX653 NPN 100V 2A ELINE 653 ZETEX BD139 NPN 80V L 5A TO126 139 MOTOR ava Copyright 2000 Linn Products Limited All rights reserved 15 AUG 00 Page 3 Type Kit Cost E N Y C N Y C N Y C N d C N Y N Y S N x E N X C N ag G N Y C N Y C N X C N Y C N Y C N ag C N Y C N ub PBOM Assembly Number Ouantity 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 Warning Part OBSOLETE on 13 MAR 1990 1 00000 ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES PRINT R R R PCAS 003 Q017 Q018 Q019 Q020 Q021 Q022 Q023 Q024 Q025 Q026 0027 0028 0029 Q030 Q031 BILL MATERIALS 15 AUG 00 Page 4 POWER AMPLIFIER PCB ASSEMBLY Units Part Number IRAN IRAN IRAN IRAN IRAN IRAN IRAN IRAN IRAN IRAN IRAN IRAN IRAN IRAN 001 001 002 001 017 002 002 002 018 001 001 017 002 002 TRAN 010 IRAN 018 OBSOLETE PART ONES BOM Type C Description Type Kit Cost ZTX753 PNP 100V 2A ELINE 753 g N Y ZETEX ZTX653 NPN 100V 2A ELINE 653 N Y ZETEX ZTX653 NPN 100V 2A ELINE 653 S N Y ZETEX ZTX753
10. Y C N X PBOM PRINT BILL Assembly Number PCAS 003 MATERIALS POWER AMPLIFIER PCB ASSEMBLY OBSOLETE PART Units Ouantity Units T C Des 1 00000 ONES R D014 MISS 001 1 00000 ONES R D015 MISS 001 1 00000 ONES R D016 MISS 014 Warning Part OBSOLETE on 07 SEP 1992 1 00000 ONES R 0001 TRAN 001 1 00000 ONES R 0002 TRAN 001 1 00000 ONES R 0003 TRAN 002 1 00000 ONES R 0004 TRAN 002 1 00000 ONES R 0005 TRAN 001 1 00000 ONES R 0006 TRAN 001 1 00000 ONES R 0007 TRAN 002 1 00000 ONES R 0008 TRAN 002 1 00000 ONES R 0009 TRAN 002 1 00000 ONES R 0010 TRAN 007 xx Warning Part OBSOLETE on 30 OCT 1996 1 00000 ONES R 0011 TRAN 007 xx Warning Part OBSOLETE on 30 OCT 1996 1 00000 ONES R 0012 TRAN 001 1 00000 ONES R 0013 TRAN 001 1 00000 ONES R 0014 TRAN 006 xx Warning Part OBSOLETE on 30 OCT 1996 Part Number ONES BOM Type C Description TYPE FUNCTION CASE 1N4148 DIODE TYPE FUNCTION CASE 1N4148 DIODE POWER AMP MAINS INDICATOR LED ZTX653 NPN 100V 2A ELINE 653 ZETEX ZTX653 NPN 100V 2A ELINE 653 ZETEX ZTX753 PNP 100V 2A ELINE 753 ZETEX ZTX753 PNP 100V 2A ELINE 753 ZETEX ZTX653 NPN 100V 2A ELINE 653 ZETEX ZTX653 NPN 100V 2A ELINE 653 ZETEX ZIX753 PNP 100V 2A ELINE 753 ZETEX ZIX753 PNP 100V 2A ELINE 753 ZETEX ZTX753 PNP 100V 2A ELINE 753 ZETEX BD140 PNP SOV 1 5A TO126 140 MOTOR BD140 PNP 80V 1 5A
11. also be checked using an ohmmeter as above Sometimes capacitors will internally short circuit so worth a quick measurement Check the components as transistors above using an ohmmeter Paul O Neill Page9 Copyright 2000 Linn Products Limited All rights reserved Contents LK2 Service Manual Power up problems Fault Table Won t power up GR MZ MZ Symptom Circumstances Possible Cause s Won t power up Power LED dead amp no function both channels Won t power up Power LED dead amp no function both channels Won t power up Power LED dead amp no function both channels Unit dies intermittently amp stops working for a while possible distortion or reduction in sound quality both channels Doesn t power up Or Powers up display LED lit but no function Or Possible distortion poor sound quality both channels One channel dead One channel dead May be intermittent May be intermittent At any time May be intermittent May be intermittent May be intermittent Fuse blown in unit and or in mains plug Mains lead faulty Power switch faulty Mains voltage dropping too low for LK2 to function correctly known as Brown outs as these voltage drops also sometimes cause the house lights to dim Wrong mains voltage for LK2 type mains voltage is too low e g 240V unit being used with 115V mains supply Transformer cable not connecte
12. considerably better than either of its predecessors How to differentiate between types of LK2 There are several methods of determining the specification of an LK2 e Looking at the serial number of a unit and using the LK2 Product History accessible via Linfo website Product Information will tell you which revision it was sold as Since however upgrade kits were sold by Linn in large quantities to allow customers to convert their early version LK2 into the latest spec many units are not what they seem The following information will help you to determine the specification of a unit if its exact history is unknown e LK280s had LK280 printed on the facia earlier units LK2 amp LK275 had LK2 printed there but beware an earlier version may have been upgraded to LK280 spec e LK260s and LK275s had a red power LED and LK280s had a green LED This is handy as a quick and easy indicator but is not 10096 reliable LEDs are easily changed e The best way to determine a unit s spec is simply to remove the sleeve and look at the boards that are fitted see below Distinguishing Features of Different Board Types PCAS 003 used 60 watt type used same board in LK260 LK275 but with some differences as shown below PCAS 020 used in LK280 Small heatsink bar with transistors fitted to it found on PCAS 020 only These diodes and Capacitor amp capacitors not fitted resistor bridged
13. in all four screws but do not tighten fully Line up the board and heatsink so that they are parallel and level with each other as diagrams above and then tighten the screws fully Tighten the nut bolt Refit boards into tray just do the reverse of the dismantling process described at the start of this document Refit sleeve Test amp fully Contents Page8 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Service Manual Fault Finding on the LK2 hints amp tips The LK2 circuitry is notoriously difficult to fault find on in the traditional way tracing signals measuring voltages etc so this manual seeks to help you to avoid this ordeal Check the fault tables below firstly to see if your fault is included and if not use the information in this section Trip One issue that may prevent you from fault finding is the inclusion of the Trip or protection circuitry which will shut down the entire board if it detects a problem that might cause damage to the amp or the speakers If trip occurs it makes fault finding very very difficult as no power reaches the amplifier section of the board If this happens it is best to try to find the fault with the power off use the information found in the Fault Tables below and in this section Isolating Faulty Components in the LK2 Circuit Common Faults Around 60 70 of faults in an LK260 or LK275 board only i e not LK280 are attributable to just
14. junction is breaking down be temperature dependent Carry out LK2 Reliability Modifications procedure can be accessed via Linfo Product Information See Fault Finding on the LK2 hints amp tips section at the beginning of this manual see Introduction to Fault Finding accessible via Linfo Product Information Or See Fault Finding on the LK2 hints amp tips section at the beginning of this manual DC at output ee WE Symptom Possible Cause s DC voltage at output Fault symptoms vary levels of voltage etc DC at output May be intermittent Faulty component in circuit Probably constant Regulator U1 or U2 faulty Page17 Contents 5 Replace faulty regulator part details U1 LM317T Voltage regulator Linn part no IC 005 U2 LM337T Voltage regulator Linn part no IC 006 See Fault Finding on the LK2 hints amp tips section at the beginning of this manual Copyright 2000 Linn Products Limited All rights reserved Paul O Neill 4 LINN LK2 60 amp LK275 Reliability Modifications Some components on the PCAS 003 used in the LK260 amp LK275 are sometimes prone to failure after many years of use This modification can be carried out as a preventative measure to prolong the life of the amplifier or as a combined repair prevention if one of the components has failed Carrying out this modification will repair around 60
15. 0 te Che PONER UP e TrE 10 WONT SWITCH OFF mu 10 PS fal Te EE 11 AMPLIFIER PROBLEMS FAULT Eege 13 FO Te CT WEE 13 TRIP PROTEC TON EE 15 IS OR ONG RAC KONG ETC 2 mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmmmmmmmmmmmm mmmmmmmmmmmmmmmmmmmmmmmmmkax kyiiin 16 BOCA i ln i ee 17 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Service Manual Introduction About the LK2 Series There were three versions of the LK2 e The first version was known at the time simply as the LK2 It gave an output of 60 watts per channel into 8 ohm load and used PCAS 003 type boards For the purposes of this manual we will refer to this version as the LK260 e The second type was also usually known as the LK2 but was often called the LK275 to differentiate it from the 60 watt version as it gave 75 watts per channel Also used PCAS 003 type boards but with several improvements over the 60 watt version the most obvious being the increased power output but also had improved protection circuitry and better sound e The third and last type was known universally as the LK280 80 watts per channel used PCAS 020 boards PCAS 020s at first glance are similar to PCAS 003s in that they are roughly the same size shape and layout but they are a completely different design of board i e not just a modified version of PCAS 003 as a closer examination shows The LK280 sounded
16. 1 115 for 115V mains MCAS 001 220 for 220V mains MCAS 001 240 for 240V mains Our stock of these transformers is very limited so it may not be possible to supply the part you Replace transformer Correct part numbers are MCAS 002 100 for 100V mains MCAS 002 115 for 115V mains MCAS 002 220 for 220V mains MCAS 002 240 for 240V mains Our stock of these transformers is very limited so it may not be possible to supply the part you require Replace faulty bridge rectifier diode s Part details MR752 6A 200V Rectifier diode Linn Part no MISS 010 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill i ui Page 12 Contents LK2 Service Manual Big capacitor s faulty probably internally short circuit Measure across both capacitors on the channel that is causing the fuse to blow a faulty capacitor will measure short circuit or certainly low impedance If in doubt compare with good channel See Introduction to Fault Finding section accessible via Linfo Website Product Information for tips on how to isolate faulty board Fault inside LK2 e g short circuit or similar Replace faulty capacitor Part details 10000uF 20 64V Electrolytic Capacitor Linn part no CAP 085 same part can be used for any version of LK2 See Introduction to Fault Finding section accessible via Linfo Website Product Information for tips on tracing the fault Also see circuit diag
17. 4 components See LK2 Reliability Modifications accessible via Linfo Product Information for instructions on how to replace these components and prevent re occurrence This modification is a good first step for a faulty PCAS 003 board and should even be carried out to working boards as a preventative measure Transistors The majority of remaining faults on an LK2 board are caused by faulty transistors so this is a good place to start If the transistors develop a fault they normally develop a short circuit zero ohms or low impedance across one or more junctions so it is usually quite a simple job to trace the faulty transistor by measuring across every junction of every transistor while the transistor is still in circuit This might seem daunting given the number of transistors on each board but it is definitely a worthwhile exercise as it may save you many hours of conventional fault finding and does not take as long as you might think about 20 minutes per board Just measure the impedance across all 3 junctions Emitter Bass Emitter Collector Bass Collector of every transistor on the faulty board In general a working junction will measure many Kohms or even Megohms whereas a faulty junction will tend to measure almost short circuit perhaps a few ohms possibly up to 500ohms at most If in doubt compare with the same junction on the good channel and replace transistor if you suspect faulty It is advised t
18. If there is a voltage remaining on these capacitors then it is important to discharge it either short across the amp contacts with a screwdriver this can cause a harmless but spectacular and territying bang combined with a huge spark It is much more pleasant to connect one of the resistors that you will use for the mod the 2 4Kohm 2 5Watt and connect this across the contacts of the capacitors until the voltage has discharged The LK2 is very heavy and has sharp fins on the heatsink be very careful when lifting handling dismantling and re assembling not to injure yourself Paul O Neill eA Copyright 2000 Linn Products Limited All rights reserved LK2 Reliability Modifications Fault Symptoms There are several different symptoms depending on what component has failed symptoms usually affect one channel only e No output at all e Bad distortion at output e DC at output Units affected Potentially all LK260s or LK275s those not upgraded to LK280 Equipment Required Those items marked may not definitely be required Workbench clear of debris and clutter No2 Posidriv Supadriv Screwdriver No1 Posidriv Supadriv Screwdriver 2 5mm Hex key or Allen Key Medium sized flat blade screwdriver 7mm spanner or nut runner 5 5mm spanner or nut runner soldering Iron temperature controlled 25 watt with fine tip oolder Sucker Fine solder Paper handkerchiefs or paper towels Heatsink compound a white grease
19. K2 on its facia and slide the sleeve up and off and carefully set it aside in a safe place where it will not get scratched or damaged Remove the 4 allen bolts or screws older units used screws holding the speaker sockets on to the back panel Do this to both channels Disconnect both transformer connectors the cables going from transformer to board from the board Lift the LK2 up so that it is standing on one of the heatsinks Each channel is held into the tray by 2 countersunk screws that attach to the heatsink on the underside Hold the channel that is now uppermost to prevent it from falling once it has been freed and remove the two screws from this channel only Lie the LK2 down correct way up and remove the channel that you have just loosened this can sometimes be tricky so follow these instructions e Pull the board slightly toward the front of the unit until the 3 pin cannon input socket at the rear is clear of the back panel it may sometimes be necessary to push the back panel slightly in the opposite direction until the socket is completely clear e Lift the end of the board containing the 3 pin cannon socket upwards see picture until that end of the board is clear of the tray Some delicate manoeuvring may be necessary but don t force it 2 Move the entire board in this direction 1 Lift this end up until clear of tray e By carefully moving the board backwards amp upwards it should now be possible
20. LINN Service Manual for LK2 Series of Power Amps Covering LK2 60 LK275 amp LK280 For the purposes of this manual we will refer to the three types as LK260 LK275 amp LK280 The term LK2 will be used as an umbrella term covering all three types i e the LK2 series CONTENTS INTRODUC TION m sii sihieis 2 ABOUTTHE LRZ S crllc 2 HOW TO DIFFERENTIATE BETWEEN TYPES eegen ERU egene ee Een 2 ABOUT THIS MANUAL e 3 RETAILER amp DISTRIBUTOR OBLIGATIONS cccesssscssrerevsesevnstecssusnavsesevsenusucrsrevasuusnvsesesrsrarsvseeessspasisrerssseess 3 SPARE PARTS AVAILABILITY AND LK2 REPAIR eict tata Eta E i ht cR LEE REI ERR RUF EL Y VY DU A c LUE EID a REB Rd RA I Rn 3 HOW TO USE THIS i OR 3 IMPORTANT SAFETY INFORMATION amp INSTALLATION ADVICE eese 4 MAIN CONNECTIONS A 4 Bie M c o P aen 4 xe m 4 PROCEDURE FOR DISMANTLING AND RE ASSEMBLING THE LK2 se 5 FAULT FINDING ON THE LK2 HINTS amp TIPS e reser ee eorr eee KEEN nnne 9 POWER UP PROBLEMS FAULT TABLE sepes eiue nonu emat rbbu T KE eS Eed RE VET SIR nee KE rS 1
21. ONES R R019 ONES R R020 ONES R R021 ONES R R022 ONES R R023 ONES R R024 ONES R R025 ONES R R026 ONES R R027 ONES R R028 ONES R R029 ONES R R030 ONES R R031 BILL Part Number RES RES RES RES RES RES RES RES RES RES RES RES RES RES RES RES RES O F MATERIALS 15 AUG 00 Page 6 POWER AMPLIFIER PCB ASSEMBLY OBSOLETE PART Units 041 023 041 042 042 043 035 035 043 082 L32 1 93 048 025 047 009 002 ONES Description BOM Type C Type Kit Cost 5K6 19 MF 1 4W 0 25W 200V 50ppm N Y 9T0R IS ME 1 4W0 25Wy 200V 50ppm y C N E SK6 T9 ME I 4W 0 25W0 200V SOON s C N Y 620R l1 9 ME 1 4W 0 25W 200V 50ppm N E 620R 1 MF 1 4W 0 25W 200V 50ppm C N Y 180R 1 MF 1 4W 0 25W 200V 50ppm C N Y 1K1 1 MF 1 4W 0 25W 200V 50ppm C N Y 1K1 1 MF 1 4W 0 25W 200V 50ppm C N Y 180R 1 MF 1 4W 0 25W 200V 50ppm C N Y ART ITS ME 1 4W 0 25W 200V 50pptt 74 C N Y ART 5 WWC XX AN 999V 999ppm C N Y ART 5 WWC XX AN 999V 999ppm C N Y 12R 1 MF 1 4W 0 25W 200V 50ppm C N Y 22K l19 ME 1 4W 0 25W 200V o50ppm N Y OR47 10 WWE W21 2 5W 100V 75ppm C N Y 2 R T ME 1 4W 0 25W 200V 50ppms N Y 150R IS ME 1 4W 0 25W 200V 50ppm N h ve Copyright O 2000 Linn Products Limited All rights reserved PBOM P
22. PNP 100V 2A ELINE 753 C N Y ZETEX ZTX653 NPN 100V 2A ELINE 653 d N Y ZETEX 2SA1386 PNP 160V 15A MT100 1386 N xX SANKEN ZIX753 PNP 100V 2A ELINE 753 C N Y ZETEX ZTX753 PNP 100V 2A ELINE 753 C N Y ZETEX ZIX753 PNP 100V 2A ELINE 753 S N Y ZETEX 2SC3519 NPN 160V 15A MT100 3519 E N Y SANKEN ZTX653 NPN 100V 2A ELINE 653 C N Y ZETEX ZTX653 NPN 100V 2A ELINE 653 C N Y ZETEX 2SA1386 PNP 160V 15A MT100 1386 C N Y SANKEN ZIX753 PNP 100V 2A ELINE 753 C N Y ZETEX ZIX753 PNP 100V 2A ELINE 753 S N Y ZETEX TYPE POLARITY o N Y MPS A93 PNP OBSOLETE 2SC3519 NPN 160V 15A MT100 3519 C N R SANKEN ve Copyright O 2000 Linn Products Limited All rights reserved PBOM Assembly Number Ouantity 1 00000 1 00000 1 00000 Warning Part OBSOLETE on 13 MAR 1990 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 PRINT PCAS 003 Units T C Des ONES R 0032 ONES R 0033 ONES R 0034 ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES ONES R R001 R R002 R R003 R R004 R R005 R R006 R R007 R R008 R R009 R R010 R R011 R R012 R R013 R R014 BILL Part Number TRAN 001 TRAN 001 TRAN 009 RES RES RES RES RES RES RES RES RE
23. RINT BILL OCE MATERIALS 15 AUG 00 Page 7 Assembly Number PCAS 003 POWER AMPLIFIER PCB ASSEMBLY OBSOLETE PART Units ONES BOM Type C Quantity Units T C Des Part Number Description Type Kit Cost 1 00000 ONES R RO32 RES 017 4K7 18 MP 1 4W 0 25 200V 50ppm C N Y 1 00000 ONES R R033 NO INFO 20K 1 MF 2 5W 200V 50ppm C N Y NOTE ORIGINAL PART FOR R033 WAS RES 045 HAD INSUFFICIENT POWER RATING USE MINIMUM l1WATT PART 1 00000 ONES R R034 RES 033 6K2 15 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R035 RES 013 180K 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R036 RES 050 OR1 10 WWE W21 2 5W 100V 75ppm C N Y 1 00000 ONES R RO37 RES 038 2K2 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R039 RES 058 33K 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R040 RES 017 4K7 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R041 RES 002 150R 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R042 RES 009 27R 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R043 RES 033 6K2 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R044 RES 013 180K 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R045 RES 038 2K2 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R046 RES 050 OR1 10 WWE W21 3 EN 100V 75ppm C N Y 1 00000 ONES R R048 RES 058 33K 1 MF 1 4W 0 25W 200V 50ppm C N Y 1 00000 ONES R R049 NO INFO 2 4K 10 WWE W21 2 5W 100V 75ppm C N Y NOTE ORIGINAL PART WAS 0 25W HAD INSUFFICIENT POWER
24. S RES RES RES RES RES MATERIALS 15 AUG 00 Page 5 POWER AMPLIFIER PCB ASSEMBLY OBSOLETE PART Units 029 017 021 078 017 030 030 030 001 001 078 022 022 023 ONES BOM Type C Description Type Kit Cost ZTX653 NPN 100V 2A ELINE 653 g N Y ZETEX ZTX653 NPN 100V 2A ELINE 653 N Y ZETEX TYPE POLARITY C N Y MPS A43 NPN OBSOLETE 1K 1 MF 1 4W 0 25W 200V 50ppm C N Y 4K7 1 MF 1 4W 0 25W 200V 50ppm C N Y 100R 1 MF 1 4W 0 25W 200V 50ppm C N xX 4K3 1 MF 1 4W 0 25W 200V 50ppm C N Y 4K7 1 MF 1 4W 0 25W 200V 50ppm C N Y 120R 1 MF 1 4W 0 25W 200V 50ppm C N Y L20Ry1 ME 1 4W 0 25W 200V 50ppm N Y DL20B19 ME 1 4Wy0 25W 200Y 50ppmy y C N X 220R 1 MF 1 4W 0 25W 200V 50ppm C N Y 220R 1 MF 1 4W 0 25W 200V 50ppm C N Y 4K3 1 MF 1 4W 0 25W 200V 50ppm C N Y 820R 1 MF 1 4W 0 25W 200V 50ppm C N Y 820R 1 MF 1 4W 0 25W 200V 50ppm C N Y OTOR IS ME 1 4W 0 25W 200V 50ppm N h ve Copyright O 2000 Linn Products Limited All rights reserved PBOM Assembly Number Ouantity 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 1 00000 PRINT PCAS 003 Units T C Des ONES R R015 ONES R R016 ONES R R017 ONES R R018
25. blem is to replace the component s listed Cure Quite simply the action that you must take to cure the problem Important Safety Information amp Installation Advice Mains connections This appliance must be earthed both for Safety and functional reasons Lethal Voltages Inside the LK2 lethal voltages are present avoid powering up an LK2 with the sleeve removed or with any live parts exposed If you must work under such circumstances DO NOT touch any part of the circuitry or any electrical connections and take great care to avoid electrocution Placement Location amp Environment Do not locate near electronic products that may transmit RF such as computers fax machines TVs etc or connect them to the same mains socket as these devices Also avoid close contact with the mains or signal leads of such products careful routing of the cable may be required Although the LK2 can usually be stacked along with other products with no problem it is better if possible to keep it apart from other products to prevent its operation being adversely affected by the heat and strong electrical field emitted by some products also since the LK2 can emit a considerable amount of heat and has a fairly strong electrical field it is better to keep it away from other devices that may be adversely affected by this Avoid locations that have high humidity or the chance of the unit getting wet Avoid locations where there is a lot of dust Handlin
26. d to board may be broken or may have a bad connection Channel has tripped Replace fuse s with correct value amp type Fuse in mains lead should be 5A Fuse in LK2 should be Slow Blow look for a T before the rating on the fuse Correct types are 100 115V 13 15A antisurge 220 240V T6 3A antisurge Replace faulty mains lead Replace power switch use Linn part no SWRL 006 Consult an electrician or your electricity supply company Check voltage rating on underside of LK2 If wrong transformer will require replacement Correct part numbers are MCAS 001 100 for 100V mains MCAS 001 115 for 115V mains MCAS 001 220 for 220V mains MCAS 001 240 for 240V mains Our stock of these transformers is very limited so it may not be possible to supply the part you Reconnect cable or repair if broken See Trip Faults section below One channel May be intermittent Board is faulty oee Amplifier Faults section dead below Won t switch off Ei La EEEEER I I Amp will not switch off using oower switch May be intermittent Faulty power switch Replace power switch use Linn part no SWRL 006 Page10 Contents Copyright 2000 Linn Products Limited All rights reserved Paul O Neill Fuse blowinc LK2 Service Manual Symptom Possible Cause s Fuse blowing Fuse blowing May be intermittent May be intermittent Doesn t power up May be intermittent Or Powers up disp
27. es look in the Glossary accessible via Linfo Website Product Information Before embarking on any Service work you should read the Service Procedures section accessible via Linfo Website Product Information as there are certain procedures that must be followed in order to ensure the problem is resolved quickly and permanently Table of contents amp fault symptoms Look firstly at the table of contents and find the category that covers the symptom you are seeing then look down the list of faults in that section until you find the symptom or symptoms that best describe the problem Circumstances Then simply follow the table along the table specifies circumstances surrounding the fault symptom e g whether the fault is likely to be intermittent or constant if the fault only occurs within a range of serial numbers etc Possible causes The next column details possible causes this is effectively the most important section probably the main reason you are looking at this manual at all There may be several possible causes for the symptom you have it is worth checking out all of these and bear in mind that there may be more than one fault For Paul O Neill Pages Copyright 2000 Linn Products Limited All rights reserved Contents LK2 Service Manual some faults simple checks are detailed that you can use to rule out the problem without replacing any parts whereas for other faults the simplest way to rule out the pro
28. es free Component R33 R49 C6 C19 uk M aa Replace with 20Kohm 2 5Watt resistor 2 4Kohm 2 5Watt resistor 68pF 160V Polystyrene capacitor 220pF 160V Polystyrene capacitor R33 is found underneath this capacitor LK2 Reliability Modifications 2 In order to prevent the two polystyrene capacitors that you have just replaced from failing at a later date make the following small adjustments to the position of some components e Bend Q10 away from C6 towards the middle of the board As shown in picture above e Bend C6 away from Q10 towards the 3 pin cannon socket As shown in picture above e Bend C19 away from Q10 towards R49 but do not bend it too close to R49 position it so that it is about half way between Q10 and R49 As shown in picture above These steps are advised because Q10 and R49 get quite hot and can sometimes melt the polystyrene capacitors over a period of many years Positioning the components as above minimises the effect of this heat and prolongs the life of the capacitors Page6 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Reliability Modifications 3 Step 4 Re assemble the LK2 1 Re attach the capacitor C16 that you removed to access R33 Use a medium sized flat bladed screwdriver to hold the head of the bolt while you screw the nut back into place Ensure nuts are tight as if they come loose later they may short out the circuitry w
29. g amp general maintenance Always handle the LK2 with great care IT IS VERY HEAVY Always turn off the LK2 and wait at least 30 seconds before connecting or disconnecting any plugs to from the sockets at the back of the unit to avoid damage to the speakers If you are carrying out any work on the LK2 with its sleeve removed ALWAYS take anti static precautions as tiny static discharges from your body which you may be completely unaware of can damage electronic circuitry and cause major problems Anti static earth mats amp wrist straps must be used when handling any of the circuit boards or any spare parts Paul O Neill Page4 Copyright 2000 Linn Products Limited All rights reserved Contents LK2 Service Manual Procedure for Dismantling and Re assembling the LK2 Step 1 Remove the boards from the LK2 Remember to keep all the screws and other parts that you remove from the LK2 in a safe place to re use later 1 Disconnect LK2 from everything and especially the mains or Spark 2 Place a soft cloth on the workbench amp lie the LK2 upside down on the cloth Using a No2 posidriv screwdriver remove the 4 screws that hold the sleeve on to the LK2 Stand the LK2 on its facia and slide the sleeve up and off Carefully set it aside in a safe place where it will not get scratched or damaged 3 Remove the 4 allen bolts or screws older units used screws holding the speaker sockets on to the back panel Do this to both channels
30. hat you check every single transistor on the board i e don t stop if you find a faulty one as quite often there is more than one faulty transistor on the board Hemember to include the big transistors the 4 that are clamped to the heatsink when measuring The above test while not absolutely guaranteed to find every faulty transistor will find the vast majority Remember that it is quite common for more than one component to be faulty as often a faulty component will cause damage to others around it in the circuit See below for advice on how to check for this Other components Other components are slightly less straightforward The same principles as with Transistors above can be applied measure using an ohmmeter but there is a lot more work involved and a lesser chance of success as these parts are less likely to go faulty and less likely to follow such a straightforward pattern as the transistors If you have a fault that is not caused by any of the faults listed in this manual i e the fault tables and this section then try to narrow the fault down to an area of the circuitry using conventional fault finding and then measure and or replace the components in that area Resistors can of course be easily measured for impedance but are very unlikely to go faulty unless another component failure has damaged them so look for telltale signs like scorching etc on or around the resistor that might indicate this The Capacitors on this circuit can
31. he service manual Linn may levy a charge and this charge should not be passed to the customer spare Parts Availability and LK2 repair Please note that the LK2 has been discontinued for some considerable time now and as such we cannot guarantee the supply of spare parts many are simply no longer available and some others are no longer in stock Some part numbers are listed throughout this manual but these are provided for information only and this does not imply that these parts will be available should you request them Linn guarantee that we will Support a product until 5 years after the final build We take this obligation very seriously and also go much further Beyond this date we will repair any Linn product that we possibly can where it is within our power to do so However due to the difficulty with the availability of soare parts as explained above it is occasionally not possible to repair a product or supply parts for repair if the necessary parts are not available How to use this manual The main body of this manual the fault table is designed to be as quick and simple as possible to use when you are confronted with a faulty product and so it is arranged by fault symptom as the symptom is usually all that you will know about the fault Also read the LK2 fault finding Hints amp Tips section below as the information contained there may save you a lot of time If you are unsure about the meaning of any words or phras
32. hile the unit is powered up and cause major damage 2 Re attach the heatsink Apply heatsink compound in a single line along the centre of the coupling block as shown below Heatsink compound l board was attached to heatsink by nuts amp bolts follow the instructions below e Remove all five bolts from the board and slide the bolts into the slots arranged as shown below Heatsink Slide the bolts into the slots positioned as shown e Place the board onto the heatsink so that all the bolts pass through their respective holes on the board some readjustment is usually necessary e Screw the nuts onto the bolts but do not tighten fully e Adjust the position of the board with respect to the heatsink so that the two are matched up i e the two are parallel with each other and neither the board nor the heatsink are protruding at either side see pictures below exaggerated to show problems clearly Heatsink Heatsink protruding not parallel from one side to board Page7 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Reliability Modifications e Once heatsink and board are matched up tighten bolts If heatsink was attached with allen screws e Slide the single nut bolt still attached to board into the middle of its slot do not tighten e Rest the board on the heatsink in a central position e Line up the screw holes in the board with those in the heatsink and scre
33. ill LK2 Service Manual Step 3 Re assemble the LK2 1 Re attach the heatsink Apply heatsink compound in a single line along the centre of the coupling block as shown below Heatsink ga compound l board was attached to heatsink by nuts amp bolts follow the instructions below e Remove all five bolts from the board and slide the bolts into the slots arranged as shown below Heatsink Slide the bolts into the slots positioned as shown e Place the board onto the heatsink so that all the bolts pass through their respective holes on the board some readjustment is usually necessary e Screw the nuts onto the bolts but do not tighten fully e Adjust the position of the board with respect to the heatsink so that the two are matched up i e the two are parallel with each other and neither the board nor the heatsink are protruding at either side see pictures below exaggerated to show problems clearly Heatsink Heatsink protruding not parallel from one side to board e Once heatsink and board are matched up tighten bolts If heatsink was attached with allen screws Page7 4 Copyright 2000 Linn Products Limited All rights reserved Contents Paul O Neill LK2 Service Manual Slide the single nut bolt still attached to board into the middle of its slot do not tighten Rest the board on the heatsink in a central position Line up the screw holes in the board with those in the heatsink and screw
34. lay LED lit but no function Possible distortion or poor sound quality Fuse blowing Fuse blowing Page11 Contents May be intermittent but usually constant Constant Wrong type of fuse fitted Mains surges Wrong mains voltage for LK2 type mains voltage is too high e g 115V unit being used with 240V mains supply Transformer faulty To check if it is definitely the transformer power down the unit replace fuse disconnect the transformer output from the Main board and power up If the transformer IS the cause the fuse will continue to blow If the fuse remains intact the fault is more likely to be on the board Bridge rectifier diode on amplifier board faulty probably internally short circuit These are the four large diodes which can be found on the underside of each amplifier board under the big capacitors Try measuring across all four with an ohmmeter if one has an internal short circuit It should be quite obvious 5 Replace fuse s with correct value amp type Fuse in mains lead should be 5A Fuse in LK2 should be Slow Blow look for a T before the rating on the fuse Correct types are 100 115V T3 15A antisurge 220 240V T6 3A antisurge Consult an electrician or your electricity supply company Check voltage rating on underside of LK2 If wrong transformer will require replacement Correct part numbers are MCAS 001 100 for 100V mains MCAS 00
35. like substance that improves heat conduction Fine Pliers Soft cloth Parts Required 20Kohm 2 5Watt resistor Qty 2 per unit 2 4Kohm 2 5Watt resistor Qty 2 per unit 220pF 160V Polystyrene capacitor Qty 2 per unit 68pF 160V Polystyrene capacitor Qty 2 per unit Note if you cannot find the above parts available in your local area some alternatives are available in the case of the resistor wattage values It is possible to use a higher wattage resistor in each case although it tends to be the case that the higher the wattage the larger the resistor and it may not be able to physically fit in the space available or may touch against another device or component especially in the case of R33 not a good idea It is possible to use a slightly lower wattage resistor in each case however if too low this will shorten the life of the resistor and the fault may re occur A minimum of 1 watt is recommended Page2 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Reliability Modifications Procedure Step 1 Remove the boards from the LK2 Remember to keep all the screws and other parts that you remove from the LK2 in a safe place Paul O Neill Disconnect LK2 from everything and especially the mains or Spark Place a soft cloth on the workbench amp lie the LK2 upside down on the cloth Using a No2 posidriv screwdriver remove the 4 screws that hold the sleeve on to the LK2 Stand the L
36. n the heatsink compound from the board and from the heatsink if you don t you will find out very quickly that heatsink compound has a knack of ending up all over your clothes hands face etc Page4 A Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Reliability Modifications Step 3 Carry out the modification 1 Locate the components as listed in the table below and replace with the values shown see pictures below for location of these components Do this for both channels Please note R49 depending on what size of part you have purchased it may be too big for the space available If so the part can be inserted to stand up as shown below R49 resistor leg bent into this shape R49 resistor body standing at 90 degrees to board Please note R33 is located underneath one of the big capacitors C16 see picture below The capacitor holder must be removed from the board to access the resistor Turn the board upside down and you will see that the capacitor holder is held by two nuts bolts Remove the two nuts and the capacitor will come away from the board but be careful as it will still be held by a pair of wires If the nuts bolts keep spinning instead of coming loose insert a medium sized flat blade screwdriver under the capacitor and press it against the head of the bolt while turning the nut this usually provides enough grip to hold the bolt so that the nut com
37. ng Part OBSOLETE on 29 MAR 1990 1 00000 ONES R D006 MISS 001 1 00000 ONES R D007 MISS 001 1 00000 ONES R D008 MISS 010 1 00000 ONES R D009 MISS 010 1 00000 ONES R D010 MISS 010 1 00000 ONES R D011 MISS 010 1 00000 ONES R D012 MISS 010 1 00000 ONES R D013 MISS 010 ONES POWER AMPLIFIER PCB ASSEMBLY BOM Type Description 22UF 20 20 10V TANT TH PCO200 C ririri ole TAG THOMSON 330NF 5 5 250V PPR TH CO900 e HLEVOX ARCOTRONIC 100UF 20 20 63V ELTR TH PCO0200 711117 ECC RUBYCON 100UF 20 20 63V ELTR TH PCO200 711117 ES T RUBYCON 4 IV ZENER OBSOLETE PART IYPE FUNCTION 1N4148 DIODE TYPE FUNCTION 1N4148 DIODE TYPE FUNCTION 1N4148 DIODE 4 7V ZENER OBSOLETE PART TYPE 1N4148 TYPE 1N4148 TYPE MR752 TYPE MR752 TYPE MR752 TYPE MR752 TYPE MR752 TYPE MR752 ve FUNCTION DIODE FUNCTION DIODE FUNCTION 6A 200V FUNCTION 6A 200V FUNCTION 6A 200V FUNCTION 6A 200V FUNCTION 6A 200V FUNCTION 6A 200V Copyright O 2000 Linn Products Limited All rights reserved CASE CASE CASE CASE CASE GENERAL INFO RECTIFIER GENERAL INFO RECTIFIER GENERAL INFO RECTIFIER GENERAL INFO RECTIFIER GENERAL INFO RECTIFIER GENERAL INFO RECTIFIER 15 AUG 00 Page 2 Type Kit Cost e N X C N b C N Y C N 2b C N Y N Y S N Y E N bs C N h G N X C N X C N X C N Y C N Y E N Y C N
38. nner or nut runner loosen the single nut bolt found beside the 3 pin cannon socket see picture below do not remove the nut completely but loosen it to the point where only a very small amount of the bolt is protruding from one side of the nut The board is now held on to the heatsink by 4 allen screws or 4 nuts bolts see picture below e f nuts bolts are fitted loosen them but do not remove them as with single bolt above pull the board upwards until there is a gap between the board and the heatsink and then slide the board to one side If the board will not move easily check that you have loosened all 5 nuts bolts If all are loosened correctly and it is still not free the board may be held on by the heatsink compound and will require some slight pressure to free it e If the board is held on by allen screws completely remove all 4 screws lift the board away from the heatsink and slide the single bolt beside the cannon socket sideways to free the board Nuts amp bolts or allen screws found at these 4 locations Loosen the single bolt found here Do not remove these two screws 3 Usea tissue or paper towel to clean the heatsink compound from the board and from the heatsink if you don t you will find out very quickly that heatsink compound has a knack of ending up all over your clothes hands face etc Step 3 Page6 4 Copyright 2000 Linn Products Limited All rights reserved Contents Paul O Ne
39. r tips on how to trace accessible via Linfo Product Information It is of course also possible that the LK2 is faulty in which case see table below Symptom Possible Cause s Tripping May be intermittent Power transistor the large Check replace power transistors clamped to the transistor s heatsink faulty Part details Q23 amp Q30 2SA1386 PNP 160V 15A MT100 Linn part no TRAN 017 Q24 amp Q34 28C3519 NPN 160V 15A MT100 Linn part no Tripping May be intermittent Regulator U1 or U2 faulty Replace faulty regulator part details U1 LM317T Voltage regulator Linn part no IC 005 U2 LM337T Voltage regulator Linn part no IC 006 Tripping Applies to LK280 U3 hybrid card faulty U3 is Replace U3 Linn part number only the small board that is IC 030 not available elsewhere connected at 90degrees to It is also worth checking May be intermittent the main board beside the replacing regulators U1 amp U2 or may be constant big caps part details above and the big resistors at either side R37 amp R46 part details 0 1ohm 10 2 5W 100V Linn part no RES Page15 Copyright 2000 Linn Products Limited All rights reserved Contents Paul O Neill Tripping Tripping Tripping Tripping May be intermittent Faulty component in circuit Applies only to LK280 Probably constant Applies only to LK275 amp later versions of LK260 Probably constan
40. rams 4 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Service Manual Amplifier problems Fault Table Symptom Possible Cause s No output from Possibly Unit not powering up see Power up problems section both channels intermittent correctly above No output from one channel Applies only to LK260 amp LK275 Probably constant No output from May be intermittent one channel OR occasionally may affect both channels No output from one channel Applies only to LK280 Probably constant No output from one channel Applies only to LK275 amp later versions of LK260 Probably constant Page13 Contents One of the Reliability Modification components has failed Amp has tripped Power transistor the large transistors clamped to the heatsink faulty It is sometimes possible to measure these transistors using an ohmmeter to check If faulty usually internal short circuit across one or more of the junctions but also there is the possibility that the transistor measures okay but is indeed faulty It will sometimes be necessary to change them to confirm or rule out this fault Power transistor the large transistors clamped to the heatsink faulty It is sometimes possible to measure these transistors using an ohmmeter to check if faulty usually internal short circuit across one or more of the junctions but also there is the possibility that the t
41. ransistor measures okay but is indeed faulty It will sometimes be necessary to change them to confirm or rule out this fault 5 Carry out LK2 Reliability Modifications procedure can be accessed via Linfo Product Information See Trip Faults section below Check replace power transistor s Part details Q23 amp Q30 2SA1386 PNP 160V 15A MT100 Linn part no TRAN 017 Q24 amp Q34 28C3519 NPN 160V 15A MT100 Linn part no TRAN 018 Check replace power transistor s Part details Q20 amp Q27 2SA1386 PNP 160V 15A TO218 Linn part no TRAN 017 Q24 amp Q31 2SC3519 NPN 160V 15A MT100 Linn part no TRAN 018 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill LK2 Service Manual No output from Applies only to Power transistor the large Check replace power one channel earlier versions of transistors clamped to the transistor s LK260 heatsink faulty Parts may be as listed in the box It is sometimes possible to above or they may be as listed Probably constant measure these transistors below depending on whether it is using an ohmmeter to check an earlier or later version of If faulty usually internal LK260 short circuit across one or Part details more of the junctions but Q20 amp Q27 TIP36C PNP also there is the possibility 100V 25A TO218 Linn part no that the transistor measures TRAN 005 oka
42. t Applies only to earlier versions of LK260 Probably constant LK2 Service Manual Power transistor the large transistors clamped to the heatsink faulty It is sometimes possible to measure these transistors using an ohmmeter to check If faulty usually internal short circuit across one or more of the junctions but also there is the possibility that the transistor measures okay but is indeed faulty It will sometimes be necessary to change them to confirm or rule out this fault Power transistor the large transistors clamped to the heatsink faulty It is sometimes possible to measure these transistors using an ohmmeter to check If faulty usually internal short circuit across one or more of the junctions but also there is the possibility that the transistor measures okay but is indeed faulty It will sometimes be necessary to change them to confirm or rule out this fault Power transistor the large transistors clamped to the heatsink faulty It is sometimes possible to measure these transistors using an ohmmeter to check If faulty usually internal short circuit across one or more of the junctions but also there is the possibility that the transistor measures okay but is indeed faulty It will sometimes be necessary to change them to confirm or rule out this fault Check replace power transistor s Part details Q23 amp Q30 2SA1386 PNP 160V 15A MT100 Linn part no TRAN 017
43. to 60 watt boards not fitted to 60 watt board Small Hybrid board fitted here at 90 degrees to main board found on PCAS 020 only SEE mm Page2 4 Copyright 2000 Linn Products Limited All rights reserved Contents Paul O Neill LK2 Service Manual About this manual This manual deals effectively with three quite distinct amplifiers The amps have enough in common to justify this approach and this avoids the confusion that might come with separate manuals Any differences between the types will be dealt with in the Circumstances column e g Applies to LK280 only This manual is designed to help you as a Linn Retailer or Distributor to repair as many LK2 faults at your repair centre as is practical and so provide the best possible service for your customer should a problem arise If you have any suggestions or comments regarding this manual please contact Paul O Neill at Linn Products Ltd By E mail PAULO LINN CO UK By Phone 44 0 141 303 5005 By Fax 44 0 141 644 4262 Marked for attention of Paul O Neill Retailer amp Distributor Obligations Linn Specialist Retailers or Distributors are obliged to carry out the repairs in this manual under the terms of the contract amp warranty agreements You should return a faulty product to Linn for repair only if the fault is not covered in this Service Manual If a product which is under warranty is returned to Linn for repair and the fault is covered in t
44. to lift it up and out of the tray e Repeat the above instruction for the other channel Page3 A Copyright 2000 Linn Products Limited All rights reserved LK2 Reliability Modifications Step 2 Remove the heatsinks from the boards 1 Using the 5 5mm spanner or nut runner loosen the single nut bolt found beside the 3 pin cannon socket see picture below do not remove the nut completely but loosen it to the point where only a very small amount of the bolt is protruding from one side of the nut 2 The board is now held on to the heatsink by 4 allen screws or 4 nuts bolts see picture below e f nuts bolts are fitted loosen them but do not remove them as with single bolt above pull the board upwards until there is a gap between the board and the heatsink and then slide the board to one side If the board will not move easily check that you have loosened all 5 nuts bolts If all are loosened correctly and it is still not free the board may be held on by the heatsink compound and will require some slight pressure to free it e If the board is held on by allen screws completely remove all 4 screws lift the board away from the heatsink and slide the single bolt beside the cannon socket sideways to free the board or TU E A l is Nuts amp bolts or allen screws found at these 4 locations Loosen the single bolt found here Do not remove these two screws 3 Use a tissue or paper towel to clea
45. w in all four screws but do not tighten fully e Line up the board and heatsink so that they are parallel and level with each other as diagrams above and then tighten the screws fully e Tighten the nut bolt 3 Refit boards into tray just do the reverse of the dismantling process described at the start of this document 4 Refit sleeve 5 Test amp fully Page8 Copyright 2000 Linn Products Limited All rights reserved Paul O Neill C LINN the only sound Linn Parts List Bill of Materials for PCAS 003 Amplifier Board for LK2 60 amp LK275 Power Amps Please note that this list is provided for guidance only Linn Products cannot guarantee the accuracy of the information contained in the list and will not be held responsible for any errors that occur as a result of its use Please double check that the details listed match the component that you are replacing How to follow a Bill of Materials BOM The BOM may at first glance seem quite confusing Once a few things are explained however you should have no problems following it The main part of this document i e the table is split into nine columns as shown in the example below Quantity Units T C Des Part Number Description Type Kit Cost 1 00000 ONES R C001 CAP 003 22UF 50 20 50V ELTR TH PCO100 C Y Y rr rrr NCC RUBYCON MLLARD Ignore all columns except for the middle three these contain all the information you require as e
46. xplained below C Des Component Designator Every component on every Linn circuit board has an individual identification code known as a Component Designator C001 Q012 R345 etc The designator shown in the table matches that printed on the circuit board beside each component These designators are coded according to type of component at the start of each designator there is a letter and this describes the component type The main types are shown below C Capacitor P Connector Q Transistor R Resistor U IC The components are listed in alphabetical order by Component Designator Part Number Our internal part number for the component Quote this part number if ordering the part from Linn We advise however that you try to source parts locally as most components are commonly available from any good electronic parts supplier much faster and cheaper than we can supply and also not every part listed here can be ordered from Linn If you have problems finding the part locally we will do our best to help you but we cannot guarantee availability of any part listed Description All the technical details that you will requireto order the part from your local or national electronic spares supplier Includes if applicable the name s of our preferred manufacturer s for each part ava Copyright 2000 Linn Products Limited All rights reserved 15 AUG 00 Page 1 Type Kit Cost PBOM PRINT BILL O MATERIALS Assembly
47. y but is indeed faulty It will sometimes be Q24 amp Q31 TIP35C NPN necessary to change them to 160V 15A TO218 Linn part no confirm or rule out this fault TRAN 004 No output from May be intermittent Regulator U1 or U2 faulty Replace faulty regulator part one channel details U1 LM317T Voltage regulator Linn part no IC 005 U2 LM337T Voltage regulator Linn part no IC 006 No output from Applies to LK280 U3 hybrid card faulty U3 is Replace U3 Linn part number one channel only the small board that is IC 030 not available elsewhere connected at 90degrees to Take great care when removing May be intermittent the main board beside the U3 from the board as it is very or may be constant big caps easy to rip tracks The pins in the middle are especially difficult to de solder use heat amp patience not force It is also worth checking replacing regulators U1 amp U2 part details above and the big resistors at either side R37 amp R46 part details 0 1ohm 10 2 5W 100V Linn part no RES No output from May be intermittent Faulty component in circuit See Fault Finding on the LK2 one channel hints amp tips section at the beginning of this manual Page 14 Copyright 2000 Linn Products Limited All rights reserved Contents Paul O Neill LK2 Service Manual rip protection problems Important information about the Trip Protection circuitry About Trip
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