Tandberg-TD20A-tape-sm 维修电路原理图.pdf

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1、TANDBERG TD 20 A-SECircuit Diagrams andAlignment InstructionsRadioFans.CN 收音机爱 好者资料库Electrical adjustments TD 20A-SEMake the adjustments in the order in which theyare listed here. Many of the adjustments requirethat previous adjustments have already beencorrectly made.Clean and degauss the tape path

2、 before and afteradjustments. lt is assumed that the tape path hasalready been correctly adjusted as described in theService Manual for the TD 20A, part No. 714127.Maxell UD XL or equivalent tapes should be usedfor recording.Necessary equipment- d.c. voltmeter.- 2 high impedance voltmeters (do NOT u

3、seuniversal meters).- Frequency counter.- Audio generator.- Distortion meter.- Wow meter (required for wow test only).- Test tapes:No. 2 - Azimuth adjustment playback head,15,000 Hz,7/z ips.No. 3 - Playback cule, DIN 19H,7%ips.No. 4 - Playback level adjustment, 4OO Hz,7% ips.No. 11 - Speed check, 10

4、00 Hz, 7%ips.Bias Adjustment (front panel)Before adjustment, make sure that the Bias Adjust-ment potentiometers on the front panel are in themid-position.Checking the oscillator frequencyConnect a frequency counter directly to the recordhead.Adjust the frequency to 123.5 kHz in stereorecording with

5、C313 on the logic board. Thencheck in mono, left and right, that the frequencyare within !.2 kHz. lf outside the tolerance, adjustC303, DUMMY LOAD ADJ. on the audio board.Then check the frequency in stereo and mono leftand right.Checking the Bias Adjustment (front panel)Connect an audio-generator to

6、 LINE 1. Start stereorecording at7%ips speed of a22kHz signal 30 dBbelow normal recording level (0 dB). Set theMonitor switch to Tape. Check that the outputlevel measured with a.c. voltmeters on the LINEOUT are within approximately + 3 dB to - 5 dBwhen turning the Bias Adjustment potentiometers.Adju

7、stment of EOT/BOT sensorTo be performed without tape. Measure with a d.c.voltmeter on pin 3, contact 412 on the logicboard.Adjust R422 (on the logic board) to 1.2 V readingon the voltmeter.A,4Test AdjustmentNo. or checkTest tape Set theNo. deck toMeasuringtnstrument Measure atAdjustCorreclreadinoSpe

8、edComments1.1 Azimuth,playback head2 Playback.c,-r:-.:-.LquoI4oLrvrr.Normal.voltmetersLINE OUTAzimuthscrew,playbackheadMaximumoutput, seecomments7% iosMaximum output or best compromtse.1.2 PlaybackcuryeDIN 19H3 Playback.Equal ization:Nomal.a.c.voltmetersLINE OUTPlaybackE.Q. adj.R501 /R601+2dBat 18 k

9、Hz7% ips.Playback curue, DIN 19H, The tape containsthe following frequencies: 1000 Hz (reference)18 kHz, 15 kHz, 10 kHz, 4 kHz, 125 Hz, 40 Hz1000 Hz (ref.). Ad.iust R501/R601 to + 2 dBat 18 kHz.1.3 PlaybacktNet4 Playback.Equalization:Normal orSomiala.c.voltmetersLINE OUTPlaybacklevelR I 69/R2690.9 v

10、olt7h ips.1.4 Speed11Playback.FrequencycounterLINE OUT! o.5/.995-1005 Hzin 7% ios.Test taoe No. 1 1 * is recorded at1000 Hz in 7% ips. Test tape No. l 1 is supplied on a small reel. This test tape should be spliced into a tape on a larger reelalRadioFans.CN 收音机爱 好者资料库TesNo.Adiustmenlor checkMeasurin

11、ginstrument Measure atSet thedeck toMonitorswitch ioProcedure2.1Biaspre-adjustmenvoltmetersLINE OUTRecord.Speed: 7% iplEqualization:Normal.TapeConnet an audio-generator to LINE 1. Set the generator to 1Z.b kHz 30 dB belownormal r*ordjng level (0 dB). Adjust RlSl and R251 to maximum outour level.Then

12、 turn R151 and R251 counter clockwise to - 2 dB from maximum readino.11Azimuth,rsord heada.c.voltmetersLINE OUTRecord.Speed: 77: ip:Equalization:Normal.TapeConnst an audio-genemtor to LINE t. Start rcording at 7% ips. of a10O0 Hz signal 30 dB below normal recording level (O dB). Use the voltmeter re

13、adings asreference level. Then rmord a 25,000 Hz signal and turn the azimuth screw on the recordhead to maximum reading or best compromise on the voltmeters.2.5Record/playbackcuruesvoltmetersLINE OUTRecord.Speed: 7% ipsEqualization:Normal.TapeConnst an audio-generator to LINE 1. Start rmording of a

14、1000 Hzsignal 30 dB below normal recording level (0 dB). Use the voltmeters readings as referencelevel (0 dB). Then turn the generator to 12.5 kHz and adiust R151 and B25l to 0.5 dBfrom the reference level. Turn the generator to 25 kHz and adjust R139 and R23g to0 dB. Check that the output level do

15、not deviate more than J 2 dB from20 Hz to 25,000 Hz.Record/playbackcuryesvoltmetemLINE OUTB ecord.Speed: 15 ips.Equalization:Normal,TapeUse the same recording level as in test 2.3. Use the voltmeters readings as reference level.Check that the output level do not deviate more than 1 3 dB from 20 Hz t

16、o 30.000 Hz.Adjust if necessary with PLAYBACK E.O. ADJ. B5O1/8601 and,/or BIAS ADi. R151/R251. lf re-adjustment is done, check once again that the output lwel in 7% ips,Equalization: Normal do not dwiate more than r 2 dB from 20 Hz to 25,000 Hz.Adiust if necessary with R139/R239.Record/playbackcurye

17、svoltmetersLINE OUTBecord.Speed: 15 ips.Equalization:Special.fapeUse the same recording level as in test 2.3. Use the voltmeters readings asreference level. Turn the generator to 30 kHz and adjust R135/8235 to 0 dB.Chek that the outDut level do not dwiate more than i 2 dB from 20 Hz to 30.000 Hz.2.6

18、Record/playbackcuruesa,c.voltmete6LINE OUTRecord.Speed: 7% ipsEqual ization:Speria l.TapeUse the same rffording level as in test 2-3. Use the voltmeters readings as refereancelevel. Check that the output level do not deviat more than i 2 dB from20 Hz to 25.000 Hz.Source,/Tapea.c.voltmetersLINE OUTRe

19、cord.Speed: 7% ipsEqualization:Normal.Source/TapeConnect an audio-generator 1000 Hz to LINE 1. Adjust in Source with the Input Levelsto 0.6 V on the voltmeters on the LINE OUT. Set the deck to stereo recording 3nd set theMonitor switch to Tape. Then adjust R142 and F.242 so that the level reading is

20、 1 dBhigher on the voltmeters.2.6ProgrammeteradjustmentvoltmetersLINE OUTSpeed: 7% ipsEqualization:Normal.SourceConnect an audio-generator 1000 Hz to LINE 1. Set the Monitor switch to Source.Adiust with the Input Levels to 1.5 V reading on the voltmeters. Then adjust the programmeters to 0 dB with R

21、158 and R258 (Output Left and Right on maximum).2.9DYNEOleveladjustmentProgrammetersLINE OUTSpeed: 7% ipsEqual ization:Normal.SourceConnect an audio generator to LINE 1. Set the generator to 1 kHz. Adjust with theinput levels to - 3 dB on the program meters. Then set the generator to 1 8 kHz andset

22、the program meters to + 2 dB with the oYNEQ SENSITIVITY ADJ. (on leit sideof the chassis).2.1C Distortionvoltmeter/distortionmererLINE OUTRecord.Speed; 7% ipsEqualization:NormalTapeConnmt an audio-generator at 1000 Hz or the distortion meter generator to LINE 1.Record to 0.9 V reading on the voltmet

23、ers and read the distortion on the LINE OUTDistortion maximum 0.5%.2.11Wow andflutterWow andfluttermeterLINE OUTRecord.TapeConnet the wow and flutter meter to LINE 1. Read on the LINE OUT in highest andlowest speed:3% ips. 7%ips. 15 ips.Wow and ilutter maximum:Weishted RMS OJO% 0.05% 0.m%Peak value

24、DIN 45500 P.4. O.14y 0.08% 0.06%OSC. FREO. ADJ. IS ON THE LOGIC 8OARO.PLAYBACK EO. ADJ. IS ON THE PLAYBACK AMP. BOARD.LRaaR15r R25tBIAS ADJ,OUMMY LOAD ADJ,ac303;PLAYB. R169 LLEVEL B .METERADJI qrqnR269 -REC. LEVEL LRaa Rt42R242R REC. EQ. ADJ.aaLi|ffl?:i n,?sn?rs-oi. Low HtGHRaR258METER AOJ,Location

25、of Adjustment points on the Audio Board, solder side-fi* -)6;l *- FE p;l l* ti* F-.E Fi FLJ LJ L.J u u Ll lmr*rff r-imir-tEffiE| - I L-J t-ri -Function Control Board, solder sideC 9Scqn rll-,+ dF, T,fi+A-+199-+ tr,2sf sLPw ?f : 1 l-*ry-icR 904e-.-.Rectifier Board, solder siljtl 1,$*s,HI- + FFf ffi +

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27、 Board, solder sidelliJtt*ll$llo,l;l-l:ll+: cs,rgurTSt.tttBBqJi l-Lol:+ *r.tPI J 109 7, .125A 510/v ttr.+l l|._tbaaalaal #a *F1- IcR 904HFTc 903+ r*1-t *t-Ld-c 905 cR solce06 .Jl-. |-.+.*.t ;1h*;t,-L/1-Jil-l,/oulmupre s F rarcrrro .0.,1.o, . -; L , ,OMP i171/1-Jtl9s15-111 05 1,r-r116 15 .,. .sR a38

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33、Na t, e a-i: ,.F -1l!l| ,:-_/:t; IllL -t-.-l .L I I ni- 6I oT- aI l*l;IT:IswlTCH i:CtOl 0lC6PART oF LoGtc BoARD NoEOat- - - - Il23kHz BIAS/ERASE OSC. lo.oo II or2 | 1.t12Audio DiagramFrcI LOGIC HL PLAY/FASI WINO/FREEL L ALL OHEF XOOESREC. AMPi -tii.:rTIi TrJL5J.-JL_J5liEOUAL.PLAYB. AMPPART OF BOARD

34、NO.63607Az.o(DI(J- =aT4D-l_t;t:IIJ3f,t-!r3ol-r? R?70 c?35 R2?l: i106 FRoM Lo6rc:-_-, _)_ LrrtPrsoF: :!. H L rN alr orqtRL tt MoDEs.PARI OF BOARD NO. 53607BOOSTER,L.P FILTER DL.CHT t00ifiABG;1BoARD NO.63685 |,/ERASEi5C-_loo o,o I;-l )LtL zDUMMY LOADFROMLOGIC AL PLAY/fW /FREf2tzNICINTCI56k2 ?OR2-M220Rroii2t5l2 0rrk5a2trwg33oR32R32kTandberg The European AlternativeTandberg A/SFetveien 1, P.O. Box 53oa-Eco-Eoo-ooEz;ocIrsrzoO-rrN-2007 Kjeller, NorwayA