Here’s some photos from a pair of Orange Crush guitar amps I’ve had in for repair: a 15R and a 30R.
Both had a very loud hum when the amp was at idle.
In a solid state amp this is almost always due to poor power supply filtering. and further inspection showed that this was caused by the same fault in both amps, namely one of the electrolytic filter caps had failed catastrophically. Below are photos of the offending items (almost!) in situ.
Orange 30R filter cap failure
Orange 15R filter cap failure
And here’s the rest of the filter cap from the 15R, which I found in the bottom of the amp.
I replaced both filter caps in each amp with better quality units rated for 105degC and this sorted the problem (as expected!).
