Yamaha-GX-900-Service-Manual电路原理图.pdf

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1、GX-900 GX-900 100674 SERVICE MANUAL GX-900 MINI COMPONENT SYSTEM IMPORTANT NOTICE This manual has been provided for the use of authorized YAMAHA Retailers and their service personnel. It has been assumed that basic service procedures inherent to the industry, and more specifically YAMAHA Products, a

2、re already known and understood by the users, and have therefore not been restated. WARNING:Failure to follow appropriate service and safety procedures when servicing this product may result in personal injury, destruction of expensive components, and failure of the product to perform as specified.

3、For these reasons, we advise all YAMAHA product owners that any service required should be performed by an authorized YAMAHA Retailer or the appointed service representative. IMPORTANT:The presentation or sale of this manual to any individual or firm does not constitute authorization, certifica- tio

4、n or recognition of any applicable technical capabilities, or establish a principle-agent relationship of any form. The data provided is believed to be accurate and applicable to the unit(s) indicated on the cover. The research, engineering, and service departments of YAMAHA are continually striving

5、 to improve YAMAHA products. Modifications are, therefore, inevitable and specifications are subject to change without notice or obligation to retrofit. Should any discrepancy appear to exist, please contact the distributors Service Division. WARNING:Static discharges can destroy expensive component

6、s. Discharge any static electricity your body may have accumulated by grounding yourself to the ground buss in the unit (heavy gauge black wires connect to this buss). IMPORTANT:Turn the unit OFF during disassembly and part replacement. Recheck all work before you apply power to the unit. ICONTENTS

7、TO SERVICE PERSONNEL .12 FRONT PANELS .3 REAR PANELS .4 SPECIFICATIONS .5 INTERNAL VIEW .6 DISASSEMBLY PROCEDURES .716 VOLUME RANGE .17 SYSTEM CONTROL CHECK .17 TEST MODE .18 SYSTEM TEST MODE.18 RECEIVER TEST MODE .1920 TAPE TEST MODE .20 CD TEST MODE .21 ALL FUNCTION TEST MODE.22 CD ERROR MESSAGES

8、.22 CD STANDARD OPERATION CHART .2326 TAPE ADJUSTMENTS .2729 MD TEST MODE Possible symptoms are, the clamp does not move up or down, the table does not turn, mecha. sensor switch malfunctions, etc. The normal operation may be restored by tuning off the power once and then on again. If it does not wo

9、rk in this way, disas- semble the CD mechanical unit and investigate the cause of the failure. 22 GX-900 GX-900 I CD STANDARD OPERATION CHART Press OPEN/CLOSE key. Forced feed return operation. Clamp down operation. Disc table reset. Tray open. Tracking Offset auto ADJ. (only POWER ON) Focus Offset

10、auto ADJ. (only POWER ON) Load a disc in “DISC 1”. Press PLAY key or push the tray. Tray closed. Table rotate. Disc research. Disc mechanism unit clamped up. Feed inward switch research. Laser ON. Disc scan. FOCUS Gain rough ADJ. FOCUS Search operation. FOCUS LOCK servo ON. Spindle motor accelerated

11、. TRACKING servo ON. Disc servo ON VCO lock. Tracking Gain rough ADJ. Tracking Balance ADJ. (only Tray OPEN/CLOSE) “OPEN” appears in the TIME indicator. “TRV” signal is output until detection of LIMIT switch. DISC “1” is turned to DM clamp position. LDON = “H” (IC5, 40 pin) FLOCK = “H” “L” (IC11, 8

12、pin) TLOCK = “H” “L” (IC11, 11 pin) FOCUS BALANCE ADJ. FOCUS GAIN ADJ. TRACKING GAIN ADJ. 23 A GX-900 GX-900 24 * Data fetch cycle TRACK No. “1” is searched. PLAY Set to SEARCH by means of Y, T key. MUTE ON. TRACK search. After searching the beginning, MUTE is cancelled. PLAY MUTE ON. Spindle motor

13、stop. Laser OFF. Forced feed return. STOP : MUTE = “L” “H”, “0:00” appears in the time indicator. (IC11, 64 pin) * TOC READ After searching the beginning, MUTE is cancelled. Press the STOP key. : MUTE = “H” “L” : MUTE = “L” “H”, “0:00” appears in the time indicator . : LDON = “H” “L” (IC5, 40 pin) :

14、 FLSW = “L” (IC11, 26 pin) A GX-900 GX-900 G CLOSE operationG HOME operation LOAD MOTOR reverse rotate Start LOAD SW OFF ? NO YES TIMER 10ms LOAD SW ON ? NO YES LOAD MOTOR STOP END LOAD SW OFF ? NO YES LOAD MOTOR forward rotate TIMER 10ms LOAD SW ON ? NO YES G OPEN operation LOAD MOTOR reverse rotat

15、e Start UNLOAD SW OFF ? YES 10sec timer start LOAD MOTOR STOP END 10sec timer time up ? NO YES LOAD MOTOR STOP ERROR NO TIMER 10ms UNLOAD SW OFF ? YES NO G DOWN operation LOAD MOTOR forward rotate Start DOWN SW ON ? YES 10sec timer start END 10sec timer time up ? NO YES LOAD MOTOR STOP ERROR NO TIME

16、R 10ms DOWN SW ON ? YES NO LOAD MOTOR forward rotate Start LOAD SW ON ? YES 10sec timer start LOAD MOTOR STOP END 10sec timer time up ? NO YES LOAD MOTOR STOP To OPEN operation NO TIMER 10ms LOAD SW ON ? YES NO 25 GX-900 GX-900 26 G ROTARY TRAY initialization operation Start POSITION SW OFF ? YES RO

17、TARY MOTOR forward rotate 10sec timer time up ? YES ROTARY MOTOR STOP ERROR NO 10sec timer start Timer 20ms POSITION SW OFF ? YES DISC NO. count STOP SW OFF ? YES DISC NO. 3 ? YES DISC NO. clear NO ROTARY MOTOR retard STOP SW ON ? NO YES ROTARY MOTOR STOP ROTARY MOTOR 32ms back pluse STOP SW ON ? YE

18、S Timer 60ms NO STOP SW ON ? YES NO Overrun count Overrun count = 3 ? YES NO ERROR Overrun count clear END NO NO 10sec timer time up ? 10sec timer time up ? YES POSITION SW ON ? Timer 20ms POSITION SW ON ? YES YES POSITION SW OFF ? NO NO YES YES NO NO NO NO GX-900 GX-900 ITAPE ADJUSTMENTS 1. Before

19、adjustment GSince head magnetization, dust accumulations, etc. are likely to introduce error in the various character- istics, it is very important that the heads are properly demagnetized and cleaned. GMake adjustments of mechanical system, playback system and recording system in that order. GExcep

20、t for azimuth adjustment, adjust in the forward direction. GAdjust at TAPE TEST MODE. 2. Instruments required GAudio frequency oscillator GACVM or dual channel (ACVM) GDCVM GWow/flutter meter GOscilloscope GFrequency counter GTorque meter TW-2111A (TX911580) . Take up/back tension (FWD) TW-2121A (TX

21、911570) . Take up/back tension (RVS) CT-160L (TX911120) . FF/REW 3. Test tape required GMTT-111N (TX911650). Normal speed GMTT-114N (TX911680) . Azimuth GMTT-212N (TX911660) .Playback level GMTT-256 (TX911300). Playback frequency response (Normal) GMTT-356 (TX911310). Playback frequency response (Cr

22、O2) GReference tape Type I/Normal (LH). TDK AC225 (VU167200) Type II/High (CrO2) . TDK AC514 (VU167300) G Test point 27 VR6 VR5 VR7 VR4 VR1 VR3 VR2 IC6 REC LEVEL ADJ. (Lch) REC LEVEL ADJ. (Rch) TAPE SPEED ADJ. PB LEVEL ADJ. (Lch) PB LEVEL ADJ. (Rch) BIAS ADJ.(Lch) BIAS ADJ.(Rch) GX-900 GX-900 “MECHA

23、NICAL ADJUSTMENT” Item to be Adjusted Check each torque Check FF, REW take up time Azimuth Tape Speed Wow/Flutter Tape CT-160L (FF, REW) TW-2111A (FWD) TW-2121A (RVS) AC-514 (C-60) MTT-114N 10kHz, 10dB MTT-111N 3kHz, 10dB MTT-111N 3kHz, 10dB Step 1 2 3 4 5 Mode FF REW PLAY FF REW PLAY PLAY PLAY Rati

24、ng FF, REW torque : within 70 160g/cm. Take up torque : 30 70g/cm. Back tension : 1.5 6g/cm. 80 to 120 seconds. Playback output of L and R is maxi- mum and phase difference should be minimum both directions. (Fig. B) 3000Hz 15Hz Less than 0.19% (WRMS) Remarks After the adjustment make sure to apply

25、screw lock paint. Perform adjustment at the center of the test tape, if possible. Confirm at center of the test tape, if possi- ble. Instrument required Torque meter ACVM Oscilloscope Frequency counter Wow/flutter meter Adjustment part Azimuth adjustment screw. (Fig. A) VR7 OK Rec out L : ch 1 Rec o

26、ut R : ch 2 DC input, X-Y (Resurge) mode NG Fig. B 0.2V 0.2V “ELECTRICAL ADJUSTMENT” GUse 560 mV (250 nwb/m) for 0 dB as the standard level of the unit. 0dB = 250 nwb/m (315 Hz) = 7 dBV (Rec out level) Item to be Adjusted Playback level (315Hz) Confirmation of playback frequency response Step 1 2 Ra

27、ting 7 dBV 0.3 dBV Check that the 10kHz playback level is within 0 3 dB of the 1kHz playback level. (Fig. C) Adjustment parts VR4 (L ch) VR1 (R ch) Tape MTT-212N 315Hz, 250nwb/m Test tape for frequency check. 3180s + 120s (LH) (MTT-256) 3180s + 70s (CrO2) (MTT-356) Points of measurement REC OUT REC

28、OUT Mode PLAY PLAY Instrument required ACVM ACVM Oscilloscope G PLAYBACK FREQUENCY RESPONSE 4dB 3.5dB 1k 3dB 3dB 3k10kHz3152505012.5kHz Fig. C Fig. A 28 Azimuth adjustment screw. (REVERSE) Azimuth adjustment screw. (FORWARD) GX-900 GX-900 Rating Adjust for equal record and playback levels. ( 27 dBV

29、0.3 dBV) Adjust for equal record and playback levels. ( 27 dBV 0.3 dBV) Adjust for equal record and playback levels. (Fig. D) Perform record bias adjust- ment of High (CrO2) tape again, if the rating was not satisfied. Confirm recorded level rat- ing as in step 1 When re- corded level rating is im-

30、proper, go back to step 1 and also carry out adjust- ments in step 2 again. Item to be Adjusted Recording level Recording bias (Total frequency response) Confirmation of recorded level Step 1 2 3 Points of measurement REC OUT REC OUT REC OUT Mode REC PLAY REC PLAY REC PLAY Instrument required ACVM A

31、udio frequency oscillator ACVM Audio frequency oscillator ACVM Audio frequency oscillator Measurement conditions Input 1 kHz Signal to AUX IN from Audio Frequency Oscillator. Adjust output level of Audio Frequency Os- cillator so that the voltage of REC OUT becomes 27 dBV. Input 12.5 kHz Sig- nal to

32、 AUX IN from Audio Frequency Os- cillator. Adjust output level of Audio Frequency Os- cillator so that the voltage of REC OUT becomes 27 dBV. Tape AC-514 High (CrO2) AC-514 High (CrO2) AC-225 Normal (LH) AC-514 High (CrO2) Adjustment parts VR6 (L ch) VR5 (R ch) VR3 (L ch) VR2 (R ch) GTOTAL FREQUENCY

33、 RESPONSE ( 27 dBV) Dolby NR B & OFF Type I (Normal)/Type II (High) Fig. D 29 5dB 5dB 1k 3dB 4dB 3k10kHz3152505012.5kHz GX-900 GX-900 MD TEST MODE 1. How to set to the test mode 1) In the STANDBY mode, press the STANDBY/ON button while pressing the RANDOM button and the PLAY/ PAUSE(CD) button. “AUTO

34、 pre-adjustment - AUTO adjustment - RESULT preparation - RESULT - MANUAL pre-adjustment - MANUAL adjustment - EEPROM setting G Extension cable (see connection diagram on page 35.) High reflecting discTDYS1 (SONY) for reproduction (P/No. TX945850) Low reflecting discCommercially available mini disc f

35、or recording Low reflecting discMMD-318 for pre-adjustment (P/No. AAX04890) TypeTest disc1. Extension P.C.B. for servicingTX946230 2. 2-pin extension connector for servicingTX946200 3. 6-pin extension connector for servicingTX946210 4. 5-pin flat cable for servicingTX946190 5. 28-pin flat cable for

36、servicingTX946220 TypePart No. 3. How to cancel test mode Caution) The AUTO pre-adjustment and AUTO adjustment modes are used for adjustment during servicing. Other modes are used when checking the specific measured values and adjusted values or when changing the set value and the adjusted value. No

37、te that use of other modes will rewrite RAM and EEPROM. 1) Finish the AUTO pre-adjustment and AUTO adjustment. ( “COMPLETE” appears on the display) 2) Press the a(MD) button. ( “TEST END” appears on the display) 3) Eject the disc by pressing the EJECT button. 4) Turn off the power. GWhen using a new

38、 combination of a mechanical pickup and an MD P.C.B. after a repair or for some other reason, make sure to set to the TEST mode and perform AUTO pre-adjustment and AUTO adjustment accord- ing to the following procedure. 1) Set to the TEST mode and perform AUTO pre-adjustment and AUTO adjustment. 2)

39、Cancel the TEST mode by pressing the a(MD) button. (Writing into EEPROM starts from here.) 3) Eject the disc by pressing the EJECT button. 4) Turn off the power. I MD TEST MODE & ADJUSTMENT 30 GX-900 GX-900 Description of TEST modes 1. AUTO pre-adjustment modeAutomatic pre-adjustment is performed. (

40、Grating adjustment mode after this adjustment.) _ AUT _ YOBI _ Adjusted values are output by using the interface. 2. AUTO adjustment modeAutomatic adjustment is performed. AUTO _ AJST _ Adjusted values are output by using the interface. Continuous reproduction is performed. (Error rate on display, j

41、ump test) 3. RESULT preparation modeNot used (Do not use this function as it is not for servicing) _ RST _ YOBI _ 4. RESULT mode (main adjustment)Not used (Do not use this function as it is not for servicing) _ RESULT _ _ _ 5. MANUAL pre-adjustment modeNot used (Do not use this function as it is not

42、 for servicing) _ MNU _ YOBI _ 6. MANUAL adjustment modeNot used (Do not use this function as it is not for servicing) _ MNU _ AJST _ 7. EEPROM setting modeVarious factors of the digital servo function are changed manually. EEPROM _ SET Each servo function is turned on independently. The voltage is

43、measured at the temperature detect terminal and the standard value is set. 8. TEST-PLAY modeContinuous reproduction from the specified address is performed. TEST _ PLAY _ C1 error rate is measured and ADIP error rate is measured. 9. TEST-REC modeContinuous recording from the specified address is per

44、formed. TEST _ REC _ _ 10. INNER modeThe position where the INNER switch is turned ON is measured. _ _ INNER _ _ _ 11. EJECT modeTo TEMP setting (of EEPROM setting) _ _ EJECT _ _ _ To CONTROL setting (of EEPROM setting) Laser power setting (record/reproduction power) is performed. 1. AUTO pre-adjust

45、ment modeLow reflecting disc (MMD-318) only StepSetting methodRemarkDisplay 1 2 3 4 5 Set the Test mode to STOP. Load a disc. Press the REC/PAUSE(MD) button once. Grating adjustment is performed and adjusted values are output. Adjustment is completed. When adjustment is OK, press the CHARACTER butto

46、n. When adjustment is NG, press the CHARACTER button. No disc is loaded. Auto pre-adjustment menu Auto pre-adjustment is started after sliding to the innermost track. “ * ” changes in the following order during automatic adjustment. HAo - RFg - SAg - SBg - PTG - PCH - GTG - GCH - RCG - SEG - RFG - SAG - HAO - HEO - TCO - LAO Proceed to Step 4 when adjustment is OK. Proceed to Step 5 when adjustment is NG. The display returns to the AUTO pre-adjustment menu. There is an abnormality at the