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fastvideo 16th July 2008 07:24 PM

Rotel rcd951 need help troubleshooting
No problem loading or eject cds, spindle motor just turn a bit and stop.
Replaced new laser unit, laser light doesn't turn on, lens does move up and down, no rf signal output.
No disc shown on display.

Mooly 17th July 2008 07:07 AM

Whats the pickup -- KSSxxx type ? Did you unsolder the shorting link on it (solder blob ).

fastvideo 17th July 2008 11:27 AM

KSS-213B, the shorted link was unsolder.

Anyone has a service manual ?

I am using sony cdp-c260 manual that I found from this forum as a reference, they use the same servo and rf amp circuitry.

Mooly 17th July 2008 11:44 AM

Are you 100% sure the laser is not lit. It will only light during "focus search" and they can be hard to see. DO NOT LOOK DIRECTLY and no closer than 12 inches. 95% of the energy is in the infra red. Is the spindle motor OK. Try unsoldering it and running it from PP3 battery for a few seconds each way to clean up the commutator.

fastvideo 17th July 2008 01:41 PM

Just spent an hour on it.
Laser doesn't light up.
This is a new laser deck unit.
laser is fine, tested it manually.
Possible the RF amp is defective?? Rare!!!

Mooly 17th July 2008 05:03 PM

Very rare -- yes. It's not a CX20108 is it ? no they must be too old. Dare I even ask how you tested the laser manually :) A faulty laser can still light with enough current, but it just behaves like a side emmiting LED with no lasing action.
When you say Laser Deck unit do you mean all the chassis -- motors and all ?
Can you measure any laser current, there is often a resistor you can measure the volt drop over and calculate. The last three digits of the serial number on the pickup give the current in milliamps for example xxxxxxxx476 would be 47.6 milliamps.

fastvideo 17th July 2008 07:22 PM

Yes, all chasis.
RF amp is CXA1821M

anatech 17th July 2008 07:28 PM

Hi fastvideo,
Absolutely, measure the laser current. Also monitor the F OK signal if you can. That indicates a focus lock.

If your RF amp is defective, then your old head assy should be okay. A new transport may not always be good. I have seen the turntable height off. That will sometimes prevent the spindle from turning, or at least prevent a focus lock.


Leolabs 18th July 2008 01:50 AM

Have you check the flat cable connect from the laser pick-up to the pcb???

fastvideo 18th July 2008 03:22 AM

Yes, I have checked the flat cable. No cracks.
Same voltage reading at both ends.
Page 8, get no voltage at collector.

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