Help. I've a borrowed old Britool 151 which has given up. I'm told its the rectifier at fault (blows fuses) and repair is uneconomic. Any ideas? Normally I'd scrap it but It's not mine.
Hi, I work on cinema arc lamp supplies which have the same basic circuitry as most Mig welders.
One or more diodes has failed to short circuit.
You could replace the rectifier section farily easily. Easiest if it's made up out of screw in diodes as opposed to swage in diodes.
If it's screw ins then all you need to do is get the numbers, purchase replacements, and change them (do use heatsink paste).
If it's the swaged in type, you can't replace them so easily, but you may be able to obtain a pre-made rectifier assembly. Or with a bit more work replace it altogether with one made up of screw in type diodes.