Linn-LK1-pre-sm 维修电路原理图.pdf

20th August 1999 LK1 Service ManualPage1 Copyright 1999 Linn Products Limited. All rights reserved.LK1 LK1 PreAmplifier Service ManualPreAmplifier Service ManualCONTENTSINTRODUCTION . 2ABOUT THIS MANUAL. 2RETAILER & DISTRIBUTOR OBLIGATIONS . 2SPARE PARTS AVAILABILITY AND LK1 REPAIR . 2HOW TO USE THIS MANUAL. 2INSTALLATION. 3IMPORTANT SAFETY INFORMATION. 3INSTALLATION INSTRUCTIONS. 3PLACEMENT. 3POWER-UP PROBLEMS. 5POWER UP PROBLEMS . 5FUSE BLOWING. 6DISPLAY & CONTROL PROBLEMS. 7GENERAL DISPLAY & CONTROL PROBLEMS . 7REMOTE CONTROL PROBLEMS . 9CONTROL VIA FRONT PANEL .10AMPLIFIER PROBLEMS.11AUDIO (LISTEN) OUTPUT.11TAPE (RECORD) OUTPUT .13RadioFans.CN 收音机爱 好者资料库20th August 1999 LK1 Service ManualPage2 Copyright 1999 Linn Products Limited. All rights reserved.ContentsIntroductionAbout this manualThis manual is designed to help you as a Linn Retailer or Distributor to repair as many LK1 faults at yourrepair centre as is practical and so provide the best possible service for your customer should a problemarise.If you have any suggestions or comments regarding this manual, please contact Paul ONeill at LinnProducts Ltd: By E-mailPAULOLINN.CO.UKBy Phone+44 (0) 141 303 5005By Fax+44 (0) 141 644 4262 Marked for attention of Paul ONeillRetailer & Distributor ObligationsLinn Specialist Retailers or Distributors are obliged to carry out the repairs in this manual under the terms ofthe contract & warranty agreements. You should return a faulty product to Linn for repair, only if the fault isnot covered in this Service Manual. If a product, which is under warranty, is returned to Linn for repair andthe fault is covered in the service manual, Linn may levy a charge and this charge should not be passed tothe customer.Spare Parts Availability and LK1 repairPlease note that the LK1 has been obsolete for some considerable time now and as such, we cannotguarantee the supply of spare parts many are simply no longer available. Some part numbers are listedthroughout this manual, but these are provided for information only and this does not imply that these partswill be available should you request them.Linn guarantee that we will service a product until 5 years after the final build. We take this obligation veryseriously 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 spare parts, asexplained above, it is occasionally not possible to repair a product or supply parts for repair, as thenecessary parts are not available and can no longer be sourced.How to use this manualThe main body of this manual, the fault table, is designed to be as quick and simple as possible to use whenyou are confronted with a faulty product and so it is arranged by fault symptom as the symptom is usually allthat you will know about the fault.If you are unsure about the meaning of any words or phrases, look in the Glossary. (accessible via LinfoWebsite - Product Information)Before embarking on any Service work, you should read the Service Procedures section (accessible viaLinfo Website - Product Information), as there are certain procedures that must be followed in order toensure the problem is resolved quickly and permanentlyTable of contents & fault symptomsLook firstly at the table of contents and find the category that covers the symptom you are seeing, then lookdown the list of faults in that section until you find the symptom or symptoms that best describe the problem.CircumstancesThen 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 serialnumbers etc.RadioFans.CN 收音机爱 好者资料库20th August 1999 LK1 Service ManualPage3 Copyright 1999 Linn Products Limited. All rights reserved.ContentsPossible causesThe next column details possible causes this is effectively the most important section, probably the mainreason you are looking at this manual at all. There may be several possible causes for the symptom youhave it is worth checking out all of these (and bear in mind that there may be more than one fault). Forsome 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 problem is to replace the component(s) listedCureQuite simply the action that you must take to cure the problem.InstallationImportant Safety InformationMains connectionsThis appliance must be earthed both for Safety and functional reasons.Lethal VoltagesInside the LK1, lethal voltages are present, although normally these are inaccessible inside the transformercasing and at the mains switch (which is insulated with heatshrink sleeving.) If the mains switch is properlyinsulated, none of the wires to/from it are damaged and the transformer casing is closed, the LK1 is quitesafe to work on while powered up as only low voltages are found on the circuit boards (maximum 38Vac and22V dc)Installation InstructionsImportant the LK1 Inverts the phase of the signal to the power amp, therefore to achieve absolute phase,connect the positive output of the power amp to the negative (black) loudspeaker terminal and the negativeoutput to the positive (red) loudspeaker terminal.If, however, you use a speaker switching box or a headphone adaptor box however, these must be wired INPHASE or damage to the power amp, headphones etc can result.PlacementLocation & EnvironmentDo not locate near electronic products that may transmit RF, such as microcomputers, fax machines, TVsetc, or connect them to the same mains socket as these devices. Also avoid close contact with the mains orsignal leads of such products careful routing of the cable may be required.Avoid locations where direct sunlight can shine on the display as sunlight (even diffused sunlight) is a strongsource of infra-red light & this causes problems with the units remote control circuitry.Avoid certain types of artificial lighting, such as low energy bulbs, fluorescent light etc, as these emit stronginfra-red patterns that can lock up the LK1 control functions.Although the LK1 can usually be stacked along with other products with no problem, it is better if possible tokeep it apart from other products to prevent its operation being adversely affected by the heat and strongelectrical field emitted by some products.Avoid locations that have high humidity or the chance of the unit getting wet.Avoid locations where there is a lot of dust.20th August 1999 LK1 Service ManualPage4 Copyright 1999 Linn Products Limited. All rights reserved.ContentsHandling & general maintenance.Always handle the LK1 with great care.Always turn off the LK1 and any Power Amps connected to it before connecting or disconnecting any plugsto/from the sockets at the back of the unit. Wait at least 10 seconds after switching off the power ampsbefore unplugging from the back of the LK1 to avoid damage to the speakers.If you are carrying out any work on the LK1 with its sleeve removed, ALWAYS take anti-static precautionsas tiny static discharges from your body, which you may be completely unaware of, can damage electroniccircuitry and cause major problems. Anti-static earth mats & wrist straps must be used when handling any ofthe circuit boards or any spare parts.20th August 1999 LK1 Service ManualPage5 Copyright 1999 Linn Products Limited. All rights reserved.ContentsPower-up problemsPower up problemsSymptomCircumstancesPossible Cause(s)CureWont power up.Display dead &no functionConstantFuse blown in unit and/or inmains plug.Replace fuse(s) with correctvalue & type.Fuse in mains lead should be 5A.Fuse in LK1 should be “SlowBlow” look for a T before therating on the fuse. Correct typesare:110/115V - T300mA antisurge220/240V - T200mA antisurgeWont power up -Power LED dead,no display & nofunctionMay be intermittentMains lead faultyReplace faulty mains lead.Display diesintermittently &unit stopsworking for awhile.At any timeMains voltage dropping toolow for LK1 to functioncorrectly (known as Brownouts as these voltage dropsalso sometimes cause thehouse lights to dim.)Consult an electrician or yourpower company.Doesnt power uporPowers up(display LED lit)but no function.May be intermittentWrong mains voltage for LK1type mains voltage is toolow. (e.g. 240V LK1 beingused with 115V mainssupply.)Check voltage rating at rear ofLK1. If wrong, transformer willrequire replacement. Correct partnumbers are:MCAS 002/100 for 100V mainsMCAS 002/115 for 115V mainsMCAS 002/220 for 220V mainsMCAS 002/240 for 240V mainsOur stock of these transformers isvery limited, so it may not bepossible to supply the part yourequire.Doesnt power uporPowers up(display LED lit)but no function.May be intermittentOne of the power supplies isdead or at an incorrectvoltage level.Power supplies can bechecked at the points listedbelow:+15V - U10 (regulator)output middle leg.-15V - Q78 emitter (squarepad)+Vref - U9 pin 7-Vref - U9 pin 8+8V - Q77 emitter (squarepad)Cannot suggest a simple fix assome fault finding is required totrace the cause of the fault.See PCAS 001 Circuit Diagram(accessible via Linfo Website -Product Information)20th August 1999 LK1 Service ManualPage6 Copyright 1999 Linn Products Limited. All rights reserved.ContentsFuse blowingSymptomCircumstancesPossible Cause(s)CureFuse blowingMay be intermittentWrong type of fuse fittedReplace fuse(s) with correctvalue & type.Fuse in mains lead should be 5A.Fuse in LK1 should be “SlowBlow” look for a T before therating on the fuse. Correct typesare:110/115V - T300mA antisurge220/240V - T200mA antisurgeFuse blowingMay be intermittentMains surgesConsult an electrician or yourpower company.Fuse blowingConstantWrong mains voltage for LK1voltage setting - mainsvoltage is too high, e.g. a115V LK1 connected to 230Vmains.Check voltage rating at rear ofLK1. If wrong, transformer willrequire replacement. Correct partnumbers are:MCAS 002/100 for 100V mainsMCAS 002/115 for 115V mainsMCAS 002/220 for 220V mainsMCAS 002/240 for 240V mainsOur stock of these transformers isvery limited, so it may not bepossible to supply the part yourequire.Fuse blowingMay be intermittentbut usually constantTransformer faulty. To checkif it is definitely thetransformer, power down theunit, replace fuse, disconnectthe transformer output fromthe Main board and powerup. If the transformer IS thecause, the fuse will continueto blow. If the fuse remainsintact, the fault is more likelyto be on the Main board.Replace transformer. Correct partnumbers are:MCAS 002/100 for 100V mainsMCAS 002/115 for 115V mainsMCAS 002/220 for 220V mainsMCAS 002/240 for 240V mainsOur stock of these transformers isvery limited, so it may not bepossible to supply the part yourequire.Fuse blowingConstantBridge rectifier D3 on mainboard faulty (probablyinternally short circuit).Replace D3 Linn part no:MISS 002Fuse blowingConstantFault inside LK1, e.g. shortcircuit or similar.See Introduction to FaultFinding section (accessible viaLinfo Website - ProductInformation) for tips on tracing thefault. Also see circuit diagrams.20th August 1999 LK1 Service ManualPage7 Copyright 1999 Linn Products Limited. All rights reserved.ContentsDisplay & Control problemsGeneral Display & ControlproblemsSymptomCircumstancesPossible Cause(s)CureDisplay dead orlocked up.PossiblyintermittentUnit not powering upcorrectly.See Power up problems sectionaboveFlashing lights ondisplay(sometimesknown as Discolights orChristmas treelights)LK1 will notfunction.Sometimesintermittent maystart doing thisoccasionally andthen become more& more frequent.Symptoms mayvary.C12 on control board faultyReplace C12 Linn part no:CAP 022Flashing lights ondisplay(sometimesknown as Discolights orChristmas treelights)LK1 will notfunction.Ensure that theabove Flashinglight fault (C12)has been ruled out.Sometimesintermittent maystart doing thisoccasionally andthen become more& more frequent.Symptoms mayvary.U9 (EEPROM) on controlboard faulty.Please NoteU9 is unlikely to be the cause ofthis fault (perhaps a 1 in 50chance) but is easy to rule out IFyou have another LK1 or acontrol board or a spare U9 thatyou can try in the faulty product.If you do not have the partavailable, ignore U9.Linn part no: IC 016 (ensure U9 isprogrammed a programmed U9will have its window covered witha sticker that will normally readMK3)Flashing lights ondisplay(sometimesknown as Discolights orChristmas treelights)LK1 will notfunction.Ensure that theFlashing light fault(C12) above hasbeen ruled out.Sometimesintermittent maystart doing thisoccasionally andthen become more& more frequent.Symptoms mayvary.U7 and U8 on control boardfaulty.Replace U7 & U8 Linn part no:IC 015 for both parts.20th August 1999 LK1 Service ManualPage8 Copyright 1999 Linn Products Limited. All rights reserved.ContentsDisplay locked up no function andno sources canbe selected input LEDs willnot illuminatewhen inputselection buttonis pressed.Occurred after unitwas switched offand then on again.Battery faulty if the batteryis dead and the unit isswitched off, the unit loses itsmemory. On most units,when this happens the unitfunctions okay afterwards butloses memory. On someunits, however the displaylocks up and must be re-activated.To re-activate the display, pressand hold one of the inputselection buttons for about 5seconds. Once the display is re-activated it will stay active andwork as normal until the unit isswitched off and then this mustbe repeated.To fix permanently, replace back-up battery (BATT 1 on controlboard) and then re-activate thedisplay.Display locked up probably one,two or moreLEDs on frontpanel constantlylit.No function.Probably constantControl board requiresupgrade.Check for the following oncontrol board:Is a Pot (variable resistor)fitted at location VR1?Is a capacitor fitted at C16?Does the EEPROM (U9)have MK3 written on it?If the answer is yes to any ofthese questions, the controlboard requires upgraded.See LK1 Control BoardUpgrade sheet (accessible viaLinfo Website - ProductInformation)Display dead orlocked up.May haveoccasional DiscoLightsMay be intermittentand symptoms mayvaryBattery has leaked fluid ontocontrol board, damagingcomponents in that vicinityRemove battery, clean board,replace any components thathave been contaminated withbattery fluid.Replace battery with a new one Linn part no: MISS 011Display locked up amp will notfunction, perhapsone or twodisplay LEDspermanently lit.May haveoccasional DiscoLightsProbably constantSymptoms mayvaryU7, U8 or C12 on controlboard faulty.Replace C12 first (easy toreplace) then replace U7 & U8.Display dead orlocked up.Probably constantPower supply fault on mainboard. The control boardpower comes from theemitter (square pad) of Q77(attached to one of theheatsinks) on the mainboard. It should measure+8VFirstly check which board iscausing the fault it could be themain board failing to supply thecorrect vo