jharasym wrote:
THE VRM was not working earlier, but volume was at max (would not drop when the VRM was turned down).
Any theory on why suddenly the volume could have dropped?
Most likely, this is directly related to the original issue with the VRM, IMHO. If there was a faulty component, that component may have either totally failed or it may have caused another component to fail. Similar story if the VRM wasn't set up correctly or if there was a weak connection or ground.....the connection or a component may have failed, either independently or as a result.
First check would definitely be to do as kurtlives suggested...check the voltage at the first filter cap (C13). After that, I'd check my ground connections as well as look for any possible shorts like stray wire strands or a bent lead. Next I'd try taking the VRM out of the circuit. You should be able to bypass the VRM by running a jumper between R23 and the + side of C12.
<----AMP GURUS PLEASE CHIME IN HERE IN CASE I'M OFF BASE. If that fixes it, the problem's all in the VRM. If not, there's something else further downstream.