GFA 535 II thermal protection led lit

kheper · 23rd June 2009, 02:56 AM

I have a problem with this amp. The right channel is dead, and the thermal protection led is lit. There is scratchy noise from the right channel when the volume of the preamp is cranked up.

I have removed the covers, and I am now taking voltage readings. There is no bias voltage on the right channel, regardless of where the pot is turned. The power supply circuit to the right channel appears to be ok.

Does anyone have any experience, suggestions or pointers to help me narrow down the culprit(s)? Thanks.

kheper · 23rd June 2009, 04:01 AM

Here are the schematics. They are too big to attach within this post.

http://nekhbet.com/schema_535II_1.jpg

http://nekhbet.com/schema_535II_2.jpg

23rd June 2009, 02:56 AM	#1
kheper diyAudio Member Join Date: Jun 2007	GFA 535 II thermal protection led lit I have a problem with this amp. The right channel is dead, and the thermal protection led is lit. There is scratchy noise from the right channel when the volume of the preamp is cranked up. I have removed the covers, and I am now taking voltage readings. There is no bias voltage on the right channel, regardless of where the pot is turned. The power supply circuit to the right channel appears to be ok. Does anyone have any experience, suggestions or pointers to help me narrow down the culprit(s)? Thanks.

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23rd June 2009, 04:01 AM	#2
kheper diyAudio Member Join Date: Jun 2007	Here are the schematics. They are too big to attach within this post. http://nekhbet.com/schema_535II_1.jpg http://nekhbet.com/schema_535II_2.jpg

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