Linn LK280 Service Manual
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Linn LK280 Service Manual

Lk2 series
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See also: Owner's Manual
Service Manual for LK2 Series of Power Amps
S rvice Manual for LK2 Series of Pow
For the purposes of this manual, we will refer to the three types as LK260,
LK275 & LK280. The term LK2 will be used as an "umbrella term",
CONTENTS
INTRODUCTION .................................................................................................................................... 2
IMPORTANT SAFETY INFORMATION & INSTALLATION ADVICE ......................................................... 4
V
................................................................................................................................. 4
.......................................................................................................................................... 4
PROCEDURE FOR DISMANTLING AND RE-ASSEMBLING THE LK2..................................................... 5
FAULT FINDING ON THE LK2 - HINTS & TIPS ...................................................................................... 9
POWER-UP PROBLEMS - FAULT TABLE............................................................................................10
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.................................................................................................................................10
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...............................................................................................................................10
.....................................................................................................................................11
AMPLIFIER PROBLEMS - FAULT TABLE............................................................................................13
.........................................................................................................................................13
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.....................................................................................................................................17
Covering LK2(60), LK275 & LK280
covering all three types, i.e. the LK2 series.
......................................................................................................................... 2
.............................................................................................................................. 3
................................................................................................... 3
...................................................................................................................... 3
............................................................................................................................. 4
...............................................................................................................15
................................................................................................................16
LK2....................................................................................... 2
............................................................................................ 3
Copyright © 2000 Linn Products Limited. All rights reserved.
m s
Paul O'Neill

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Summary of Contents for Linn LK280

  • Page 1: Table Of Contents

    Covering LK2(60), LK275 & LK280 For the purposes of this manual, we will refer to the three types as LK260, LK275 & LK280. The term LK2 will be used as an “umbrella term”, covering all three types, i.e. the LK2 series.

  • Page 2: Introduction

    • 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.

  • Page 3: About This Manual

    “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.

  • Page 4: Important Safety Information & Installation Advice

    Anti-static earth mats & wrist straps must be used when handling any of the circuit boards or any spare parts. Page4 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...

  • Page 5: Procedure For Dismantling And Re-Assembling The Lk2

    By carefully moving the board backwards & upwards, it should now be possible to lift it up and out of the tray. • Repeat the above instruction for the other channel Step 2/ Page5 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...
  • Page 6 3. Use a 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 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...
  • Page 7 Heatsink Heatsink protruding not parallel from one side to board • Once heatsink and board are matched up, tighten bolts. If heatsink was attached with allen screws: Page7 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...
  • Page 8 2. Refit boards into tray – just do the reverse of the dismantling process described at the start of this document. 3. Refit sleeve 4. Test amp fully Page8 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...

  • Page 9: Fault Finding On The Lk2 - Hints & Tips

    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 4 components. See “LK2 Reliability Modifications” (accessible via Linfo – Product Information) for instructions on how to replace these components and prevent re-occurrence.

  • Page 10: Power-Up Problems - Fault Table

    Won’t switch off Amp will not May be intermittent Faulty power switch Replace power switch – use Linn switch off using part no: SWRL 006 power switch Page10 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...

  • Page 11: Fuse Blowing

    Try measuring across all four with an ohmmeter – if one has an internal short circuit, it should be quite obvious. Page11 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...
  • Page 12 Fault inside LK2, e.g. short See Introduction to Fault circuit or similar. Finding section (accessible via Linfo Website - Product Information) for tips on tracing the fault. Also see circuit diagrams. Page12 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...

  • Page 13: Amplifier Problems - Fault Table

    TRAN 018) that the transistor measures okay but is indeed faulty. It will sometimes be necessary to change them to confirm or rule out this fault. Page13 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...
  • Page 14 No output from May be intermittent Faulty component in circuit. “Fault Finding on the LK2 – one channel hints & tips” section at the beginning of this manual. Page14 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...

  • Page 15: Trip (Protection) Problems

    (part details above) and the big resistors at either side – R37 & R46 – part details: 0.1ohm; 10%; 2.5W; 100V. (Linn part no: RES 050) Page15 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...

  • Page 16: Distortion / Crackling Etc

    Power-up problem – if amp Power-up problems section may one or both receives insufficient power it above. channels will struggle to amplify the signal and distortion will occur Page16 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...

  • Page 17: Dc At Output

    (Linn part no: IC 006) DC at output May be intermittent Faulty component in circuit. “Fault Finding on the LK2 – hints & tips” section at the beginning of this manual. Page17 Copyright © 2000 Linn Products Limited. All rights reserved. Contents Paul O'Neill...
  • Page 18 • 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 Copyright © 2000 Linn Products Limited. All rights reserved.

  • Page 19: Equipment Required

    • Bad distortion at output • 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...
  • Page 20 By carefully moving the board backwards & upwards, it should now be possible to lift it up and out of the tray. • Repeat the above instruction for the other channel Page3 Copyright © 2000 Linn Products Limited. All rights reserved. Paul O’Neill...
  • Page 21 3. Use a 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) Page4 Copyright © 2000 Linn Products Limited. All rights reserved. Paul O’Neill...
  • Page 22 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.
  • Page 23 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...
  • Page 24 (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...
  • Page 25 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...
  • Page 26 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.
  • Page 27 R C017 CAP 085 10000UF,+20%,-20%,64V,ELTR,TH, PCO400,,,,,,,BHC,,,, 1.00000 ONES R C018 CAP 037 470PF,+2%,-2%,160V,PST,TH,CO900,,, C ,,,,,,,, ** Warning - Part OBSOLETE on 28-MAR-1990 1.00000 ONES R C019 CAP 038 220PF,+2%,-2%,160V,PST,TH,CO100,,, C ,,,,,,,, Copyright © 2000 Linn Products Limited. All rights reserved.
  • Page 28 MR752 6A 200V RECTIFIER 1.00000 ONES R D012 MISS 010 TYPE FUNCTION GENERAL INFO MR752 6A 200V RECTIFIER 1.00000 ONES R D013 MISS 010 TYPE FUNCTION GENERAL INFO MR752 6A 200V RECTIFIER Copyright © 2000 Linn Products Limited. All rights reserved.
  • Page 29 1.00000 ONES R Q012 TRAN 001 ZTX653,NPN,100V,2A,ELINE,653, ZETEX, 1.00000 ONES R Q013 TRAN 001 ZTX653,NPN,100V,2A,ELINE,653, ZETEX, 1.00000 ONES R Q014 TRAN 006 BD139,NPN,80V,1.5A,TO126,139, MOTOR, ** Warning - Part OBSOLETE on 30-OCT-1996 Copyright © 2000 Linn Products Limited. All rights reserved.
  • Page 30 R Q029 TRAN 002 ZTX753,PNP,100V,2A,ELINE,753, ZETEX, 1.00000 ONES R Q030 TRAN 010 TYPE POLARITY MPS A93 OBSOLETE ** Warning - Part OBSOLETE on 13-MAR-1990 1.00000 ONES R Q031 TRAN 018 2SC3519,NPN,160V,15A,MT100,3519, SANKEN, Copyright © 2000 Linn Products Limited. All rights reserved.
  • Page 31 ONES R R011 RES 078 4K3,1%,MF,1/4W,0.25W,200V,50ppm,,, C 1.00000 ONES R R012 RES 022 820R,1%,MF,1/4W,0.25W,200V,50ppm,, C 1.00000 ONES R R013 RES 022 820R,1%,MF,1/4W,0.25W,200V,50ppm,, C 1.00000 ONES R R014 RES 023 910R,1%,MF,1/4W,0.25W,200V,50ppm,, C Copyright © 2000 Linn Products Limited. All rights reserved.
  • Page 32 ONES R R028 RES 025 22K,1%,MF,1/4W,0.25W,200V,50ppm,,, C 1.00000 ONES R R029 RES 047 0R47,10%,WWE,W21,2.5W,100V,75ppm,, C 1.00000 ONES R R030 RES 009 27R,1%,MF,1/4W,0.25W,200V,50ppm,,, C 1.00000 ONES R R031 RES 002 150R,1%,MF,1/4W,0.25W,200V,50ppm,, C Copyright © 2000 Linn Products Limited. All rights reserved.
  • Page 33 NOTE – ORIGINAL PART WAS 0.25W – HAD INSUFFICIENT POWER RATING. USE MINIMUM 2.5W PART 1.00000 ONES R R050 RES 078 4K3,1%,MF,1/4W,0.25W,200V,50ppm,,, C 1.00000 ONES R R051 RES 063 18R,1%,MF,1/4W,0.25W,200V,50ppm,,, C Copyright © 2000 Linn Products Limited. All rights reserved.
  • Page 34 R R057 RES 009 27R,1%,MF,1/4W,0.25W,200V,50ppm,,, C 1.00000 ONES R R059 RES 018 15K,1%,MF,1/4W,0.25W,200V,50ppm,,, C 1.00000 ONES R U001 IC 005 LM317T,VOLTAGE REGULATOR,TO220, 317T,NATSEM, 1.00000 ONES R U002 IC 006 LM337T,VOLTAGE REGULATOR,TO220, 337T,NATSEM,THOM Copyright © 2000 Linn Products Limited. All rights reserved.

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Lk275Lk260

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