Rotel rcd951 need help troubleshooting

fastvideo · 16th July 2008, 07:24 PM

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.

-Chris

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.
CXA1821M
Page 8, get no voltage at collector.

16th July 2008, 07:24 PM	#1
fastvideo diyAudio Member Join Date: Jan 2005 Location: montreal	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.

17th July 2008, 07:28 PM	#8
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	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. -Chris __________________ "Just because you can, doesn't mean you should" © my Wife

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17th July 2008, 07:07 AM	#2
Mooly diyAudio Member Join Date: Sep 2007	Whats the pickup -- KSSxxx type ? Did you unsolder the shorting link on it (solder blob ).

17th July 2008, 11:27 AM	#3
fastvideo diyAudio Member Join Date: Jan 2005 Location: montreal	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.

17th July 2008, 11:44 AM	#4
Mooly diyAudio Member Join Date: Sep 2007	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.

17th July 2008, 01:41 PM	#5
fastvideo diyAudio Member Join Date: Jan 2005 Location: montreal	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!!!

17th July 2008, 05:03 PM	#6
Mooly diyAudio Member Join Date: Sep 2007	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.

17th July 2008, 07:22 PM	#7
fastvideo diyAudio Member Join Date: Jan 2005 Location: montreal	Yes, all chasis. RF amp is CXA1821M

18th July 2008, 01:50 AM	#9
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	Have you check the flat cable connect from the laser pick-up to the pcb???

18th July 2008, 03:22 AM	#10
fastvideo diyAudio Member Join Date: Jan 2005 Location: montreal	Yes, I have checked the flat cable. No cracks. Same voltage reading at both ends. CXA1821M Page 8, get no voltage at collector.

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