Acoustic b200; no sound

[Dante Tejeda]

Hello,
I recently recieved a non operational acoustic b200 bass amp head from a friend, and thought it would be a good project to work on.
The amp powers on, the electric fan goes round and round, but when I connect the amp to a speaker, there is no sound. Not even the red clipping light flashes when I press my finger against the other end of the guitar cable.
I though it might have something to do with the pre amp, it still might be that, but when I opened the amp head, besides being somewhat dusty, all the resistors, capacitors, and what have you looked fine.
If anyone has any info on this or shared a similar experience, your input would be much appreciated
Thank you~

 

[abarson]

Welcome to TB!
Did your friend specify what isn't functioning? What happens when you plug a bass in? Just touching the cable tip probably isn't enough to cause the signal clip light to flash, but you should hear something.
It doesn't sound to me that you have a background in electronics, which is really necessary to troubleshoot an amplifier. You've done a visual inspection and nothing stood out, but you need knowledge and tools to go any further.

 

[Pocket4]

My B200H is also dead quiet. Though I like this head for it's class A/B grunt I'm not sure it's worth paying out to fix.

 

[BassmanPaul]

Does the brute have an Effects Loop? If yes link send and return with a signal cable to eliminate that from the diagnosis.

 

[BassLife77]

Its STK404-140 output IC that always blows in these amps. It the black thing mounted to the heat sink. The part is cheap and if you know how to solder its an easy fix