Braun CD3 saved from the tincan factory..

[Dateq]

Hi everyone,

Hope someone could help me to save this guy, and give it alot more years of musical fun.
Saved this nice player from the cold streets. He was waiting to be recycled to something that I drink out off waiting for a train.....

Couldn't wait to take a peek inside this heavy piece of art metal.
Plugged it in, nothing works, no lights etc.
But what would you expect?

Resoldered some cold joints, cleaning en lubricating the main known parts.
Now it spins and reads the tracks nicely. Also the display and the disc light works nice.
Only there's no sound but it's all static sound and sometimes a big pop sound.

Could anyone tell me where to look?

[j baldam]

Hi, it depends on whether you want it to owe you some cash.
If you don't mind speculating, then I would buy a new laser as a start.

[guido]

Disk spins, reads tracks. So why a new laser........... Spare?

As for fixing; find the datasheets of the chips used and start measuring. First powersupply voltages. If those are ok, check the signals (a scope would come in handy).

[j baldam]

hi, just thought to be logical, start at the start with known good laser.

[Dateq]

Could the laser have a defect?

It reads like a normal cd player only there are plops and ticks instead of music.

I can even skip the tracks, ff en rev them.

[stephensank]

The CD3 is basically a Sony CDP-302. Although it's possible there might be a bad electrolytic cap or soldering around the signal processor chip, the most likely fault is that either the error correction RAM chip is bad or the signal proc chip itself is bad. Replace the RAM chip first, as it's cheaper & easier, and if problem remains, you'll have to find & replace the DSP chip.

[SoNic_real_one]

Originally Posted by guido

Disk spins, reads tracks. So why a new laser........... Spare?

Maybe because the laser reads only the audio data from four of the diodes and the other two detector diodes are doing the tracking? Maybe just the one/two receivers are bad. Or de associated focus error amplifier is uncalibrated.

Anyway, without a scope, there is just so little you can do (get a schematic, measure supply voltages).

[stephensank]

Originally Posted by SoNic_real_one

Maybe because the laser reads only the audio data from four of the diodes and the other two detector diodes are doing the tracking? Maybe just the one/two receivers are bad. Or de associated focus error amplifier is uncalibrated.

Anyway, without a scope, there is just so little you can do (get a schematic, measure supply voltages).

That never happens, at least that I've ever seen, and definitely not with this laser. There is absolutely no doubt, knowing these players as I do, that it is either the error correction RAM chip or the signal processor chip, with a small chance that a fault around these chips is disturbing their operation. Seriously.