The original disc surface is perfect as far as i can see. Yes it does play other original discs but i find it is very fussy with discs ie producing this whirling static noise on a lot of discs.
Quan
Lmao!!!
And for those who are completely confused...........IPA Isopropyl alcohol
Although a pint of medical grade pale ale might work as well. Can't say for sure as I've never tried!!!cheers!!!! hic!
LMAO, definitely medical grade for sure-cheap and cheerful- 99 percent alcohol not the weaker Whisky type.
Thanks Ricardo. I hope so.
So I tracked down the cause of the disc spinning wildly. It was a broken trace on the digital power supply to the decoder.
I still have no display. The disc tries to read repeatedly but fails. The +/-12v rails are fine, but there's a very low voltage into Q851 (less than 1v).
Edit: Hmm.. . only seeing 4v AC into U311, U312. That's wrong, isn't it?
Edit again: Oh no, sorry, it is right. Doop-de-do...
So I tracked down the cause of the disc spinning wildly. It was a broken trace on the digital power supply to the decoder.
I still have no display. The disc tries to read repeatedly but fails. The +/-12v rails are fine, but there's a very low voltage into Q851 (less than 1v).
Edit: Hmm.. . only seeing 4v AC into U311, U312. That's wrong, isn't it?
Edit again: Oh no, sorry, it is right. Doop-de-do...
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Calling it a day. Current status:
- No display
- Disc repeatedly spins one way, then the other, then stops.
- Sled moves correctly in service modes, but disc spins like a circular saw on a later mode.
- Tiny voltage going into Q851 (can't remember if it was negative).
- CPU, DAC and op-amps seem fine.
- No display
- Disc repeatedly spins one way, then the other, then stops.
- Sled moves correctly in service modes, but disc spins like a circular saw on a later mode.
- Tiny voltage going into Q851 (can't remember if it was negative).
- CPU, DAC and op-amps seem fine.
I don't suspect the ribbon because the display and disc reading failed at the same time. The only difference without the ribbon plugged in is the controls don't work. It tries and fails to play in both cases. The CPU is apparently working because the service mode controls work, but the disc is behaving strangely and it can't start playing the disc. Anyone know what no power into Q851 would mean?
Not to worry, at least you've ruled the ribbon out (which could have caused those symptoms). Q851 is the -18V regulator which is for the display. No voltage here probably means the zener diode next to it has failed, or the reg itself, or (most likely I think) the preceding PSU has failed. Most likely, given yours is a KI, the transformer secondary winding that feeds this has been pulled off the PCB. Have you checked the transformer?
Interesting. Well, the green wire (U305) did unfortunately break off, and it seems to be made of some sort of enchanted solder-proof wire. I thought it was conducting but I'll have to check again. I presume that's it, 12.7v. I found it tricky to follow the trace with all the diodes and omitted parts around that area.
Measured so far:
u305: 14vac
u306: 16.6vac
u307: 16.6vac
u308: 10vac
u310: 10vac
u311/12: 3.9vac
u267: 14.3vac
Measured so far:
u305: 14vac
u306: 16.6vac
u307: 16.6vac
u308: 10vac
u310: 10vac
u311/12: 3.9vac
u267: 14.3vac
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