Monkeypeas
Member
- Messages
- 156
- Location
- Staveley/Creswell, North Derbyshire, UK
Sorry, to clarify, the spot/stitch pots DO wait for the torch trigger to be pressed, if you dont press the trigger it doesnt do anything, as it shouldnt, with the trigger pressed and the pots active the contactor/relay operates but the wire feed doesnt, with the pots clicked off, nothing happens regardless of trigger input.The very high gain of a Darlington pair, where the first transistor amplifies the base current into the second transistor, causes a rapid rise in collector current. This may be so fast that your Multifunction Component Tester thinks it is dealing with a switch, and so classifies the device as a thyristor.
The 300mV that you measured across the open torch trigger switch seems low. It may be enough if it feeds to the base of a transistor. However, connecting the torch trigger direct to the base of a transistor would not be very tolerant of switching noise, and that voltage should not be unstable or decreasing. Tracing out the circuit would help to explain this. If you send the board to me, I could have a go at doing that and fixing it.
The two Spot/Stitch pots should not enable the relay and contactor when rotated to their active state, they should wait for the torch trigger switch to start a weld operation. This behaviour does at least prove that the relay coil and whatever component drives it is working.
This Polish company offers a replacement board:
The price of 239 Zloty ( "PLN" ) converts to £46, but then there would be shipping and probably Customs charges to add.MM-160 682778 MM160 367552-001 367552-880 W22E W24E
MM-160 682778 MM160 367552-001 367552-880 W22E W24Eplytkadomigomatu.pl
I ordered a few replacement components, the 3 small transistors, voltage reg and zener, i'll replace those first and let you know how it goes (still waiting on the bits, start of next week hopefully)
I'm not very good at reverse engineering pcbs, i'm more of a "that could be the problem i'll just replace it" type and i quite enjoy desoldering and re-soldering components so i dont mind messing with it, although having someone actually draw up diagrams of boards like you could eddie would definitely be helpful to anyone else down the line, i may take you up on that very kind offer (which i probably dont deserve) if this doesnt work, i'll keep you informed.
I really am tempted to sell my Eland and other migs and just keep this if/when i can fix it, despite it being rather large for its unimpressive output, its just such a smooth and easy machine to set up and use, kind of machine i could lend to anyone and not worry if the machine was on their side or not, if they struggled i'd know it was them and not the esab... maybe i'll keep my eye out for a power compact 200.