Beocenter 9000 cd repair at test stage 4

[Imdec]

Hi

I recently got hold of a Beocenter 9000 and had a look at it. The CD-player wasn’t working, and i thought/hoped it was just the quick 33µF cap replacement, but that didn’t help as it has done in earlier repairs. I’ve also recapped all the electrolytes to no help. I believe the CD unit is a CDM4/33, or at least close to it?

At the moment I’m running “testmode” but it seems not to want to pass the 4th stage, giving me a F.4.
(all stages up to this now responds well, even F.2 quickly changes to 0.2)

The 4th stage has to do with the radial motor, and it moves quite freely when not powered on, and always return to the middle stage. When test 4 is run however, the radial motor presses all the way inward, and doesn’t seem to want to move out of that position. TOC is obviously not located or read either.
I’ve been checking the signals in and out of chips and connector to try to locate something wrong.  All power-leves seems to be present and I’ve found no broken traces/solder points. Also the manual says “Does RE outlet regulate radial motoramplifier”.  Well, I don’t know. it seems to be activity on the R1 and R2 lines from IC6101, and it changes if i slightly push on the laserhead. But I can’t find any 650Hz signal on RE on pin 7 on IC6102. However I don’t know the amplitude of this signal, and if my cheap handheld oscilloscope are able to display it…

Could anyone with a working CD unit post a picture of how the signal is supposed to look like?

Any other suggestions on where to troubleshoot would be very welcome.

• This topic was modified 1 day, 14 hours ago by Imdec.
• This topic was modified 1 day, 3 hours ago by Imdec.

[Imdec]

It seems like the CD unit is actually a CDM-4/24

[Author]

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