GK 400RB III smoking fan...

[cjlectronics]

Yep, I turn this unit on and after a few seconds the fan starts smoking. I checked the voltage at the header for the fan and it measures 62vdc. Obviously this is not the correct voltage.... or maybe it is?? Anyone got a schematic and can point me in the right direction to repair it?

Thanks
CJL

[Enzo]

Well I have to ask. Is it really the fan smoking? Or is it the fan blowing the smoke from something else out of the amp?

Look at the label on the fan. WHat does it say the operating voltage is?

My GK files are all for older ones. 400RB-3 sounds like a newer one. Call GK and ask for the drawings.

[cjlectronics]

Yes, the fan is smoking. Its label reads 24vdc. I removed the heatsink (which has numerous screws) and found a TO-220 style transistor burnt(I think this is the right package? Its the same type as a TIP120). It is connected to the fan through an MPSA06. The transistor that is burnt is too burnt to read its numbers.

I have requested a service manual from GK. Haven't heard anything yet, though.

CJL

[clintronics]

Yes, the fan is smoking. Its label reads 24vdc. I removed the heatsink (which has numerous screws) and found a TO-220 style transistor burnt(I think this is the right package? Its the same type as a TIP120). It is connected to the fan through an MPSA06. The transistor that is burnt is too burnt to read its numbers.

I have requested a service manual from GK. Haven't heard anything yet, though.

CJL

You ever get that schematic. I got exact same repair. whats R31?

[clintronics]

Cool, GK just sent this