Welder repairs after loud bang!!!

[rosinante]

Until yesterday I had a working GYSMI141 inverter welder, switched it on and there was an almighty crack , the power tripped and spur fuse blew,restored power welder now totally dead , checked for 230v at the terminals with cover off , power available, now with a bang that loud I would expect to see some indication of arcing or burning, without stripping the unit further I cannot see or smell any evidence of tracking or burning,
Q 1 are these units financially viable to repair?
Q2 would a repaired unit be reliable ?
Q3 where to take it for repair?
I know this may be on the wrong part of the forum [sorry mods] but I think more peeps read this one , all useful advice gratefully recieved,
Cheers
Chris

 

[cumbriasteve]

Similar sound to when a capacitor went in my MMA machine, I don't think they are expensive but obviously you need someone with the skills and the gadgets to check them out.

 

[tigler]

That could be as simple as the power switch suppressor cap having gone short circuit then blowing. The loud crack should mean there will be evidence of something dying.

 

[PTvor]

There's a pre-charge circuit in inverters which on start up, charges the main capacitors through a resistor slowly to avoid a current surge into the main capacitors, which would blow fuses and maybe damage the inverter. When the capacitors are charged (about half a second) the inverter is ready to weld and a relay shorts out the resistor and powers the welder properly. I'd check the relay and the resistor. I recall Gys have a more complicated arrangement with relay contacts to connect in the resistor and another set to make the connection after the pre-charge is complete. It could be that the relay contacts became stuck and have now been damaged, in which case it's replacing the relay.

However, this could be all sorts of things, some very hard to diagnose without a service manual and just by using a multimeter and deduction. For instance, these are dual voltage machines so there'll be circuitry to detect the voltage and adjust for it.

If you look on the WWW there are people offering inverter repairs. I gather that their prices start at about £75, but you'd have to contact them and ask. This is a pretty old machine and you'd have to weigh the cost of repairs against buying a new inverter with a warranty.

 

[rosinante]

welder repair

New one it is then ,Thanks for replies
Cheers
Chris

 

[Shox Dr]

10Quid on it been a MOSFET. They are Amp/switches, about 10x15x3mm in size black in colour, they will be fixed to a heat sink. The manufacturers over tighten the chip to the heatsink, not able to expand as it heats up, it blows.