Hey all, especially
@dr*audio
I just picked up a Sony 507ESD single player deck for the princely sum of half a sawbuck!
This is the one with the dual TDA1541a DAC chips.
It was advertised as not working for parts or repair. I really only grabbed it to salvage the TDA chips because I've always wanted to do a DIY dac based on that chipset.
Well, now that I've got it on the bench I thought maybe I would ask what y'all thought about the viability of getting it working before I dismantle it. It occurs to me that it's probably a pretty good deck in working condition and maybe a shame to salvage it.
This is what the seller wrote me before I picked it up....
Symptoms: Loading a disk works - tray opens and closes, laser head returns to home position. If tray closes and there is no disk on it, laser recognizes this and does not spin up motor. But if there is a disk, spindle motor spins up and laser lens moves up and down to optimize focus and read disk. Usually (but not always) this is successful and the display will show the number of tracks, and total time. But when Start is pressed, disk spins continuously without track time being displayed and without any output. So it seams reading is marginal.
Diagnosis: All power supply voltages on main board are good. Motor control circuits are good. Laser driver circuit is functioning, but voltage to laser is lower and current is slightly higher than expected. I have not tried tweaking laser power level (on head) or doing any other alignments per the service manual. Those would be logical next steps.
Sure enough, when I got it home and tried it out it will load discs and read the TOC. If you press play it will just spin and not engage the 1st track. HOWEVER, I found if I fast forward to another track it would start playing but jump around on the track (like typical disc skipping, but about 10x worse).
The only thing I have done was to mark the pots for TRACK GAIN and FOCUS GAIN and tried slightly tweaking those (because I have read that you can't mess up too much by nudging those adjustments). This actually got it to play for about 30 seconds before it started skipping again. And it will read track 1 now, albeit with a lot of skipping.
SO, and it's a big SO, I know these use the KSS-151a laser which is really expensive if you can find a legit one. And like I said, I really just wanted the DAC chips. But if there's a kludge that might get another year or two of use out of the deck I am thinking it might be kind of nice to save it until there's no other choice.
Thoughts?
