Maybe the plate is putting some mechanical pressure on another part, which triggers your fault?
I’m a bit concerned that adding any kind of insulating material, like thin card or paper, would reduce the space between the plate and the optical assembly even more, which could lead to rubbing. I’ve already measured the clearance, and while it seems sufficient, any additional material could make things tighter and possibly cause the issue again.
That’s why I’m considering removing the plate entirely or, as a more permanent solution, designing a 3D-printed part that would provide a little more space while still offering protection for the electronics. But first, let me confirm my theory that the plate is the culprit. I’ll play several discs throughout this week, and if no issues arise, I’ll blame the damn plate. 😅
Probably. That’s why Im gonna test the player (without the plate) for one week.
If things are that tight then you could well have the answer...
Can the plate not be stood off a fraction with thin plastic washers?
Yes, that’s another option. The thing is, I suspect that this plate is somehow causing some kind of interference with the base of the optical assembly, although thinking that might be a bit crazy.
For now, I’ve played three discs today without the plate, and there have been no issues.
I prefer to fix things at the root, haha—if the plate is the problem, then the plate goes away!
Sorry if I am missing the obvious, but can you post a Pic of the plate in place? (Or a section of the repair manual showing it..) Seems that torsion or something to that nature may be changing the dimension for the laser focus, perhaps...such as Turbowatch2 noted earlier.
If things work well without the part, try to put it in place but don't fix it completely, just leave it in place loosely. Try again, if it works, next fix it.
I experienced all kinds of faults where such a problem was not the cause, but a pointer to the real problem.
I experienced all kinds of faults where such a problem was not the cause, but a pointer to the real problem.
I was about to take some photos of what you mentioned, and while doing so, I noticed a couple of things I hadn’t realized before:
1. The suspension of the CDM0 isn’t right. The right side of the platform where the CD is placed was slightly tilted downward. This makes me think it could be a possible cause of the optical assembly’s lower part hitting the chassis.
2. There are some cables tied together with a zip tie, running very close to the optical assembly. If those cables are slightly bent in the wrong direction, they can obstruct the optics.
So, I made two adjustments:
- I added small plastic washers to raise the suspension and lift the platform:
- I added another zip tie to secure the cables and keep them from getting in the way of the optics. In fact, when the bottom plate was installed, it applied slight pressure on the cables, pushing them toward the optical assembly.
Now everything seems to be working fine, even with the bottom chassis in place. Fingers crossed!
Thanks, everyone, for your help and comments!
Fresh news! After thinking that the player was fully repaired, I decided to reassemble it and place it in its final position, but… after a whole week of flawless testing… it failed again once assembled. So, once again, I had to take it apart and keep searching for the culprit.
Already fed up with the situation, I took a plastic probe and, while the player was running (after readjusting the focus), I started gently touching all the components one by one, slightly moving them to see if anything happened (I'm talking about the components on the CDM0 board). Then, as soon as I brushed against a specific component, the player instantly stopped working. I didn’t even move it—just touched it!
Looking closer, I realized that it was a capacitor at the very beginning of the HF signal circuit.
Here is a schematic picture:
The capacitor in question was 2110. One of its legs (marked in yellow) was barely touching the leg of capacitor 2111 (marked in red), which seemingly caused a short circuit (indicated in green). This short affected the base of the first transistor in the entire HF signal circuit.
My assumption is that the capacitor legs were close enough to create a random short circuit depending on conditions like ambient temperature or slight vibrations.
The key question is: Do you think a short circuit like this could alter the behavior of the focus correction circuit?
Already fed up with the situation, I took a plastic probe and, while the player was running (after readjusting the focus), I started gently touching all the components one by one, slightly moving them to see if anything happened (I'm talking about the components on the CDM0 board). Then, as soon as I brushed against a specific component, the player instantly stopped working. I didn’t even move it—just touched it!
Looking closer, I realized that it was a capacitor at the very beginning of the HF signal circuit.
Here is a schematic picture:
The capacitor in question was 2110. One of its legs (marked in yellow) was barely touching the leg of capacitor 2111 (marked in red), which seemingly caused a short circuit (indicated in green). This short affected the base of the first transistor in the entire HF signal circuit.
My assumption is that the capacitor legs were close enough to create a random short circuit depending on conditions like ambient temperature or slight vibrations.
The key question is: Do you think a short circuit like this could alter the behavior of the focus correction circuit?
I simply corrected the capacitor because it was bent too much towards the other capacitor. I just pushed it slightly to put it back in the correct position. I had to readjust the focus, and now it’s working fine again. For how long? Haha.
If it fails again, I’ll consider replacing the gain and offset potentiometers, as I can see changes in the HF signal just by touching them.
If you mean physically touching what might be 'open' pots then stray noise pickup would certainly effect things.
Finally, after spending a long time thinking about the issue and getting tired of not finding a definitive solution, I did what everyone recommends: reflowing the solder joints. That was the cure.
This was good perseverance. Well done
I'm currently working on a CD73. It has glitchy track lights sometimes flashes all of them up while it plays but it sounds perfect and doesn't skip.
I'm currently working on a CD73. It has glitchy track lights sometimes flashes all of them up while it plays but it sounds perfect and doesn't skip.