GFA 535 right channel out.

[sdstarnes]

Looks like the amp in my "budget" system is having problems as the right channel output stage is bad Anyone have a DIY for some basic troubleshooting? Not up on all of the electrical theroy required but can follow directions and possibly replace items if needed..

Thanks!

 

[ben62670]

Did you open it up? Any fuses blown. If fuses are blown replace rail fuses with 1 amps to test. Replace the main with a 5 amp for test reasons. Anything look burnt? Getting hum out of channel?
We need a little info.

Ben

 

[sdstarnes]

No fuses blown, no hum, nothing looks burnt, just silence on the one channel.....

 

[sdstarnes]

The channel was making a high pitch distorted sound right before it cut out........Any ideas?

Thanks!

 

[sdstarnes]

I turned the amp back on and the blown channel played for a short time, then started distorting out to a very high pitched sound when is when I shut it off. I am able to duplicate this several times....Possible output transistors???

Anyone?????

 

[mpmarino]

Do you get the high pitched squealing when no source is
connected?

 

[sdstarnes]

I believe it does it with or without a source input.......

 

[vhinze]

I'll go out on a limb here and say if it was an output transistor blown, it'd probably stay blown and take a fuse or other transistors with it.

I don't have a schematic in front of me and it doesn't sound like you do either. But if you want to poke around, I suggest getting one from one of the many websites that pedal them. Then I'd go looking at the base-emitter junctions of the offending channels driver transistors with no load hooked up to the amp. You wanna see 0.7 volts at the junction. Compare voltages with the good channel to confirm.

That's the best I can do for you "blind".

 

[sdstarnes]

Thanks!