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Looking for detailed Sony CDP-101 repair advice

Hello, I a restoring a "Goodwill find" Sony CDP-101 and looking for advice, I have the service manual, schematics, trouble shooting guide (thanks to this site), a good meter and scope, though do not have a frequency counter, nor test disk YEDS-1, and am using a "regular" CD for measurements.

Supply voltages are good, CD loads and spins up, but ejects after 6 seconds. With no CD in the tray, and covering the disk detection LED, the pickup red laser is seen (looking carefully), and the lens bounces 3 times trying to focus. With a CD in the tray, after a disk load, IC101.22 F-SRN pulses low only once, then the disk ejects after 6 seconds suggesting a problem with the disk motor servo circuit(2). Placing the unit into disk motor servo circuit checkout (pages 13-14 of trouble shooting guide) shows all is OK until the very last stage where the output of the buffer amp (IC201.5) is at fixed 1V DC, where as the buffer amp input (IC201.4) is ramping as expected. Suggesting a bad IC201.... but if RV201 is adjusted square wave activity is seen at IC201.5 the output of the buffer amp. Unsoldering the GND to IC101.17 and .19 checkout connection, going into adjustment mode then trying to follow the IC201 phase lock adjustment per the service manual page 43, only 0V is seen at TP3 however RV201 is adjusted..... confirming a disk motor servo / speed problem I think. Noticing in adjustment mode BRAKE (IC101.19) stays at 4.8V in stop or play, and CLV (IC101.17) is 0V for stop and 4.8V for play - either maybe disabling the servo circuit ?. Wonder what CLV is ?, and how BREAK works ? - these two are grounded during the disk motor servo checkout - maybe the problem is more upstream ?.

When I tie servo board TP2 to TP4 for adjustment mode this keeps the CD spinning and prevents ejecting. GFS (Servo board TP1) stays low, though the IC204 focus and tracking circuits show activity (IC204 had already been replaced by a BX1201 in place of the original STK6922). The RF signal at audio board IC402.8 looks OK, and the data processing signals are OK all through IC409.9. The PLL frequency at audio board TP7 is approx 3.3MHz instead of the expected 4.32MHz, and TP 6 oscillating at 7MHz. The 8.6MHz crystal is fine and RFCK signals derived from it OK, but the recovered clocking having a 1.6msec period instead of 1.08ms agreeing with the PLL and disk speed being low. So the unit being "repair-worthy".

Believe I have to "deep dive" into getting the motor to spin at the right speed ? - and need to understand the CLV and BRAKE functions, thanks for reading, and appreciate any advice.



Re: Looking for detailed Sony CDP-101 repair advice

Did you clean the lens?

Re: Looking for detailed Sony CDP-101 repair advice

Hello Johnny, Thanks for reply and advice - I had already cleaned the lens, and just did again (with a Q Tip and diluted dish washing fluid) with no improvement.
Digging more, believe CLV (IC101.17) is supposed to be 4.3V in STOP going to 0.1V upon a PLAY, I see the 4.3V and then 1 glip to 0V then back to 4.3V when PLAY is pushed. Wish I knew what "CLV" means and reasons for the seen action. Also notice DISK STOPN (IC101.31) supposed to be 4.1V in STOP mode, is instead glipping 4V to 0V and back, caused by I think "DSS" oscillating. Think my next step is to try and adjust the PLL for 4.32MHz in STOP mode (instead of the 3.3MHz seen). Appreciate advice from anyone who has setup a Sony CDP-101, thanks.

Re: Looking for detailed Sony CDP-101 repair advice

Make sure all your switches are clean and functional.

Re: Looking for detailed Sony CDP-101 repair advice

Thanks for the advice, switches are working except the 4 switches on the IC102 K3 control line are not "working" (meaning no click sound), though I do hear a click if I short out the IC102 D0/1/2/3 to K3 connection, and see pulses on the Dx and Kx lines with a scope, so maybe too high a resistance somewhere on the K3 circuit ?. Was planning on fixing that later (or getting a remote) after basic operation is repaired.

I did find PCB tracks open-circuit on the supply voltages to IC408, the PLL voltage buffer. With that fixed, I can set the idle PLL to approx 4.3MHz (with a scope, have a counter on order). Presently F-SRN does go low once, in adjustment mode GFS does go high (after ~10 seconds), and a CD "plays" with the tracking servo output (IC204.16) looking reasonable - so reaching the end of the trouble shooting guide (page 7/8) sequence. I am hoping a more accurate PLL frequency setting will help the motor servo circuit. When "playing" in adjustment mode the track number and timer display increments, with occasional skipping back. No audio signal is seen coming from the DAC. Wish there was a "theory of operations" for this unit, and thus I could understand what the acronyms mean, appreciate the help.

Re: Looking for detailed Sony CDP-101 repair advice

biggest problem with Sony CD players was laser assembly or motor, substitution is the best way to prove it,