Sony CDP-101 how to repair?

[PWH]

Hi,
Thanks to other members I now have the service manual and I have an STK 6922 on the way and an STK 6922s. These are rare and expensive IC's and I don't want to 'blow them up' so was wondering about the best route to restore the machine to working order.
The story: I got this from Trade me (NZ answer to Ebay) assured that it was working. Opening the package it stank of urine and had obviously been abused. I cleaned it up, plugged it in and it had the sticky drawer problem which I corrected. On powering up again, I loaded a CD and noticed smoke coming out from the STK 6922. I understand a common problem. I have left it for some months and now returned to it to try and repair. I notice that there are some RS components in there too- so it has had repairs. See photos.

I am not familiar with this technology and don't have a scope. What would your approach be? Can you see any other obvious modifications? Can a STK 6922s be substituted for a 6922?

Thanks

[FIXITNOW]

Sanyo STK6922 motor driver chips can be replaced with the more reliable Sony BX1201

[michamoo]

The smell probably was not urine but some leaking electrolytic capacitors as some smell just like stale urine. I dont hold out too much hope for getting this 1st generation CD player working without knowledge of early players and test equipment .This model was not even reliable in the 80s if honest

[Studio263]

Originally Posted by michamoo

This model was not even reliable in the 80s if honest

Never a truer word spoken! It was funny how the (European) Philips CD100 was smaller, cheaper, better and more reliable, that's normally what the Japanese do!

The two hybrid motor driver ICs are a regular problem with these players. Since they are just power op amps I replaced them with L272s, each 8 pin package contains 2 amplifiers which is ideal. All one has to do is to add is a simple network across each output to ensure stability, a 1R resistor in series with a 220nF capacitor does the trick. Pinning can be inferred from the service manual, which is really good for these. The circuit can be mounted on a little piece of Veroboard so its all nice and neat. Mine has worked with this modification installed for many years.

[PWH]

Well I have now replaced the substitute parts with new original spec parts and changed one STK6922 The other is a Bx1201 fitted by others.

The machine powers up, the door will open, close, the clamp comes down I can see the laser try 3 times then the disk is ejected. The disk does not attempt to spin
I am reasonably sure it is a matter of setting the machine up but I don't have a scope. Does anyone have a photo of the boards which shows the positions of the pots? At least if I roughly align, it might start.
Thanks

[PWH]

After adjusting the optical block start position the motor now spins, 1 comes up in the display then, as before the disk, is ejected.

[D Cassidy]

Hello.
The disc won't spin up till the optical block finds focus. If you can get it to spin up have a look at the S curve on the RF test point. The focus balance may be wildly out or even the tracking balance. Try setting up the full player according to the procedure in the manual. Sony recommend a full set up after doing the drive chip modification.

Oh I forgot don't use CD'r discs in these players or you'll shorten the life of the optical block

[PWH]

Thanks. I have set the machine up as far as I can without a scope. I have also found photos on the net of the boards showing positions of the pots. With minor tweaks to those positions, the machine now loads and spins up discs at good speed for a few seconds before being spat out. What should the PLL frequency be when idle? Where are the test points? I have set the voltages of the 2 pots on the audio board.

Thanks!!

[D Cassidy]

Hello.
I would need to borrow the manual from a friend to give you the information you need.
I can't see how it is possible to set up a CD player without an oscilloscope. The RF pattern which contains the S curve is the most important thing to examine in the process.

Your player will be now focussing but not reading the TOC, this could be due to a low RF output, tracking balance maladjusted, PLL fault or even a discoloured or dirty lens. These early players have sensitive optics and believe it or not the coating on the lens can be ruined by cigarette smoke. Carefully clean the lens with a fine cotton bud in a dilute solution of washing up liquid, Sony used to sell lens cleaner solution which is dilute detergent.

[Trigon.]

PWH, It's doesn't sound as though you have the full service manual ?

Both that and a useful 'Trouble Shooting Guide' can be downloaded from :-

https://freeservicemanuals.info/en/?...101&brand=Sony

Cheers

.

[PWH]

Thanks for the replies. I do have the manual but it seems without a 'scope I am stuck.
However I will try the lens cleaning again and check the manuals in the link .
Thanks again

[PWH]

OK so I finally got a USB scope and connected it as per the procedure in the manual and the result with procedure is in the attached pic. However, how do I adjust RV406 with the disc spinning when it is underneath the set There seems no obvious way so hopefully someone has done this before. Also looks like I have made a mistake with my scope purchase as it does not seem to have an AC setting!
Help!