So my CD jukebox is sick. For awhile it has been giving me trouble with some 700MB music CDs. It used to play everything just fine. But lately (2 years) it would only play the first half of some, not all, disks. Eventually it stopped playing any disc, resulting in an error code 61, no disc detected. I read about common issues so I replaced all the aging electrolytic capacitors on the servo and decoder boards and performed the laser current and focus adjustments using my voltmeter. Success! It was working again, but only for a few months. Again it started acting up, presenting similar symptoms. However, this time the current and focus adjustment did not help. The present symptoms are this: only the first 10 seconds of any disc, or any track, will play. After about 10 seconds the audio output gets scratchy and the disc stops. No errors, no faults. Watching from the side as the laser pickup moves, I can see it move to higher (further to the outside) tracks somewhat slowly after making a selection, maybe 1/2 a second to get to say track 15. My assumption is that is very slow. I then decided to disassemble the CD drive unit. I inspected the radial movement and spindle movements, both moved freely with no binding or sticking. I also tickled the radial motor with a small DC of only 0.9 volts and it moved freely back and forth with no issues proving to me the motor is not at fault. At this point I started focusing on the servo/tracking control board. I found no bad BJT transistors, zener diodes, or passive components, which left me to suspect the servo amplifier, L272MB. Actually my drive has a TCS0372DP2, dual power op-amp. So today I wait for my obsolete part to arrive. I hope I guessed right. Your thoughts?
See my youtube video
BTW- In the video I don’t think I was on the correct test point for the eye pattern. But I'll worry about that after I get her running better.
See my youtube video
BTW- In the video I don’t think I was on the correct test point for the eye pattern. But I'll worry about that after I get her running better.
Attachments
Last edited:
I like reading about CD player repairs to hopefully get a grasp of the tech.
Some makes sense, some seems like black magic. Like new tech often does.
Right now your just a magical wizard, casting spells in the land of music.
So that is cool.
Just curious on the operation of the circuit if it is really that sensitive to opamp type.
Low drift? low offset etc etc.
Maybe if the guess was not right, Something modern/adaptor if needed would work.
Moving up higher in the art of wizard magic.
Or in this case maybe a jukebox hero
Some makes sense, some seems like black magic. Like new tech often does.
Right now your just a magical wizard, casting spells in the land of music.
So that is cool.
Just curious on the operation of the circuit if it is really that sensitive to opamp type.
Low drift? low offset etc etc.
Maybe if the guess was not right, Something modern/adaptor if needed would work.
Moving up higher in the art of wizard magic.
Or in this case maybe a jukebox hero