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CL1 ugly dc offset


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#1 tompeary

tompeary
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Posted 17 August 2005 - 03:32 PM

I have a rush repair on my bench, a CL1 (s/n 002966) out of an aerobics studio. +40 - 55 vdc on bad channel's output, really nasty looking on my 'scope. Any known causes, or is a .pdf of the service manual available?

Thanks!

Tom Peary
Pro Audio Technician
Norman's Electronics

#2 KGring

KGring

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Posted 18 August 2005 - 02:22 PM

Tom,
If you are getting a DC measurement on the output, that channels has blown the output stage and damaged the crowbar protection circuit. I can email schematics, but the service manual is only available to authorized service centers through our secure service website.


QUOTE(tompeary @ Aug 17 2005, 03:32 PM)
I have a rush repair on my bench, a CL1 (s/n 002966) out of an aerobics studio. +40 - 55 vdc on bad channel's output, really nasty looking on my 'scope. Any known causes, or is a .pdf of the service manual available?

Thanks!

Tom Peary
Pro Audio Technician
Norman's Electronics
View Post

Kevin B. Gring
Crown Audio
kgring@crownintl.com

#3 tompeary

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Posted 18 August 2005 - 02:40 PM

I also would think shorted outputs if I got full constant rail on the output. It varies between +40 to +55 volts, the rail  voltage is +78. At first, the offset is lower, 4-6 vdc, then, sometimes, the affected channel works fine. I'm thinking diff amp problem. Also, the POWER led doesn't light.
I'll certainly thank you to email me a schematic, board layout would be nice, too.
tompeary@neiusa.com
We were at one time your authorized service center here, but we had a bad manager who blew that for us.


Thanks!

Tom Peary
Norman's Electronics
QUOTE(KGring @ Aug 18 2005, 02:22 PM)
Tom,
If you are getting a DC measurement on the output, that channels has blown the output stage and damaged the crowbar protection circuit. I can email schematics, but the service manual is only available to authorized service centers through our secure service website.


QUOTE(tompeary @ Aug 17 2005, 03:32 PM)
I have a rush repair on my bench, a CL1 (s/n 002966) out of an aerobics studio. +40 - 55 vdc on bad channel's output, really nasty looking on my 'scope. Any known causes, or is a .pdf of the service manual available?

Thanks!

Tom Peary
Pro Audio Technician
Norman's Electronics
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