Sony CDP791: "no disk" issue and cold start

[vrolok]

With 9 out of 10 CD's I try, my 20+-years-old CDP791 shows a "no disk" error.

I have tried an easy repair - simply my gently cleaning the laser lens but to no avail. 🙁

What I did notice though is that if it manages to read a CD (difficult but not yet impossible) and I let it play for a while (say 30 mins or so), then the "no disk" issue is gone! It would play anything w/o a prob.

How could I fix it up?

Does this mean I need a new laser lens: KSS240A?? Or, the problem might be elsewhere?

Thanks a lot!

 

[Mooly]

It is more than likely a problem with the KSS240. These were often troublesome in service. As with any playability issue, you should really look at the RF signal as that gives a good clue as to what may be going wrong. Spindle motors are another common problem area and can sometimes be coaxed back by applying 9 volts across the terminals to clean up the commutator but you MUST isolate the motor first.

 

[vrolok]

Thank you Mooly!

I will play with a scope and will report back.

Pfff... sounds more difficult than I initially thought.

 

[Mooly]

Its the only way to do it ! but if the spindle motor is OK there's more than a good chance it is just the pickup.

 

[vrolok]

solved!

I am so pleased my goodold cd player is now back to full life. Following Mooly's advice (and tips - thanks!) I have replaced the laser pickup. Everything just fine 😎

 

[Mooly]

Good to see it all worked out. Nice player 🙂