A popular repair we get asked to carry out is often related to 'user interface' items such as jack sockets and broken or cracking knobs. Now we're not saying musicians are heavy handed, you guys know you are already! :) We're saying it is a common thing we get asked!
Sometimes a description of the "jack hums or doesn't work unless I hold it in this position, usually I just put a bit of tape in place or wedge the cable around the handle and it works"
"I think it needs a new jack" pointing to the lack of jack in the chassis.
Unfortunately most amp brands solder the jack sockets on to the PCB so when it appears as a fairly easy job, actually requires the whole internal guts to be taken out including undoing all the knobs and nuts to get at.
The jacks are inexpensive ranging between £4 and £8 per socket and can be replaced at our workshop in Harlow Essex.
Crackling pots can sometimes exhibit almost intermittent volume issues with turned from minimum to maximum, there is often a dead spot where the volume disappears altogether or jumps around irrelevant to the actual position. This is caused by oxide, dust and other debris on the carbon tracks inside each control. Our first instance would be to spray a little switch cleaner in them as this cleans the tracks and often removes the deposits. We'll leave it soak for half hour then try, in 80% of the cases this solves it, the other 20% requires removal of the PCB as extreme as the above and replacement of the complete control. This fault usually is found with either the most adjusted levels such as the gain or master volume, and also those that are rarely touched such as the tone controls, but only once they are touched.
Pots and controls range from £2 to £8 depending upon their value, mounting and purpose.