marshall mg100 hdfx mute circuit ??

[randomhero8375]

I need some help. I had the IC chip blow so I bought a new chip and installed it; nothing happened. I figured that I messed it up so I bought the lil circuit board and installed it; still no sound. I noticed that on the main board the lights were lighting up when I was playing. I put on headphones, and I could hear myself playing. Thats where I am at now. What do I do now?

[Amp Kat]

Try the send or preamp out if you have one to another amp. Any sound ? Try the return in from another preamp source. Any sound ? Why did you think it was the mute circuit at first ?

[Jazz P Bass]

Standby voltage

Check pin #9 of the output IC. TDA 7293 if i am not mistaken.
This is the standby pin. It has a slow ramp up at Power On. Pin #4 is standby ground.
The components are over on the right. Nowhere near the IC.
The headphone out is a separate circuit.

[randomhero8375]

Try the send or preamp out if you have one to another amp. Any sound ? Try the return in from another preamp source. Any sound ? Why did you think it was the mute circuit at first ?

i thought that it was that because of other forums that I have read. This is my first troubleshooting experience with a guitar amp. I will check that out thanks for your reply.