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-   -   need help with gallien krueger 800rb (http://www.diyaudio.com/forums/solid-state/55557-need-help-gallien-krueger-800rb.html)

dkdeleon 17th April 2005 09:45 AM

need help with gallien krueger 800rb
 
im not getting any out put, everything lights up but no output.
im thinking its output transisters??????
any help :xeye:

andjur78 17th April 2005 10:16 AM

If it was the Output Stage then it probably would have blown the line fuse. They normally go short and cause an imbalance at the O/P. Can you obtain a schematic and post it here or email?
I may be able to steer you thru repairing it....

Enzo 19th April 2005 05:07 AM

With two channels or output power, I would agree that output transistors is probably not it. Unless a channel has failed and took out the 60v supplies or their fuses.

Make sure the 60 volt rails are present. Make sure the +/-15VDC rails for the op amps in the power stages are present.

Make syre the +/-15VDC rails are present in the preamp curcuits as well..

COnnect the effects send jack to the inout of another amp. If you can hear it there, then the preamp is at least partly working. Likewise, plug a guitar into the effects return.. That woukd check the power amp and later section of the preamp.

Is there a signal on the Direct Out jack?

Make sure the Biamp/Full Range switch is working - check the resistance at its contacts.

dkdeleon 22nd April 2005 12:02 PM

i caint find a shcematic on this amp do you have one?

dkdeleon 25th April 2005 11:17 PM

2 Attachment(s)
here are the schematics

dkdeleon 25th April 2005 11:19 PM

2 Attachment(s)
and more

dkdeleon 25th April 2005 11:21 PM

2 Attachment(s)
and this is the last one. sorry so many post but file was to big for just one

dkdeleon 25th October 2005 09:37 AM

Quote:

Originally posted by Enzo
With two channels or output power, I would agree that output transistors is probably not it. Unless a channel has failed and took out the 60v supplies or their fuses.

Make sure the 60 volt rails are present. Make sure the +/-15VDC rails for the op amps in the power stages are present.

Make syre the +/-15VDC rails are present in the preamp curcuits as well..

COnnect the effects send jack to the inout of another amp. If you can hear it there, then the preamp is at least partly working. Likewise, plug a guitar into the effects return.. That woukd check the power amp and later section of the preamp.

Is there a signal on the Direct Out jack?

Make sure the Biamp/Full Range switch is working - check the resistance at its contacts.

I pluged my guitar in the fx return and got sound. what does this meen?

Enzo 26th October 2005 05:36 AM

That means the power amp is working. That means the output transistors for that power amp are working. it means the problem is in the preamp or the effects loop jacks themselves.

dkdeleon 28th October 2005 02:24 AM

how could it be in the effects loop jacks???
and thanx for all your help


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