Yamaha T100C

[Doc Stitches]

I am posting some pictures this time and hope they will help solve the mystery.

Problem... amp plays only with very low volume and has a lot of distortion.

All advice appreciated.

Doc

[Enzo]

Pictures don;t tell me much.

What voltages are going on in the power amp? HAve you plugged a signal into the power amp in jack or the FX return jack? Have you sent the preamp signal from either the FX send or the preamp out jack to some other amp for a listen?

HAve you substituted known good tubes into the amp?

Have you tried more than one speaker cab?

[JerryP]

I've seen several of these amps come thru here with a failed resistor near that 47 uf cap on the main board. If I remember right that was the symptoms they had too. Check the resistors around that tube on the back corner of the board near the power supply board to see if any are open.
Jerry

[Doc Stitches]

Yamaha T100C

Hey Enzo and Jerry....Thanks for your help. Found/fixed problem : bad 1/2 watt resistor near V3. Amp sounds like new.

Doc