Here's one I had to repair.
On taking the covers off the first thing that alarmed me was that the insulation card board ( prespahn) was not installed correctly.
The way it was positioned provided no protection from the Live Mains switch terminals and the adjacent Low voltage wiring . This struck alarm bells that this had been previously disassembled .Undoing the four nuts on the back of the Banana sockets allowed the Printed Circuit Board (PCB) to be separated from the Front panel ( I think this is what Ocker was referring to )
This revealed that one of the four bridge rectifier diodes had been previously replaced with a different type to the others ......this is bad practice ....a set of four should be replaced with identical types .
Measuring the forward voltage drop with a multimeter of all four diodes showed that the problem was again one had gone short circuit and was tripping the cut out .
Also evident was that the Over Voltage Protection Zeners had been "snipped out " and not replaced .When driving light bulbs and rheostats these are not needed but they do "clamp" High Back EMF voltages generated by induction coils and solenoids and protect the diodes .Why they had been snipped out and not replaced is a mistory
Repairs aren't repairs and some can do them and some shouldn't . ......so if a wire had come off the back of the mains switch and had flicked over and contacted the Low voltage wiring ....how would you explain that .......Just sayin
Repeated diode failure is one thing , potential for lethal accident is another .
