LTSUK Super 200P Chinese Multipurpose welder problems

[poxxxy]

Hi guys,

I know its a long shot but hoping someone may be able to assist in helping me diagnose and repair my Super 200P multi purpose welder.

At the moment I do not have argon to be able to test the TIG function, I will be visiting my Grandpa to see if he has any stick welding rods later to try out that function although i'm not hopeful.

All I have available to test at the moment is compressed air for the plasma cutting function... I plugged it all in a couple of days ago with a 70psi feed and the unit turns on without any fault light lit... Ground clamp in the positive output and torch connected to the Gas/electrical output terminal. However upon pulling the trigger on the torch (or footpedal) I get nothing from the machine... no relays clicking, no gas flow through torch, no arc, no HF buzz, absolutely nothing.

I took the cover off the machine and discovered that the top board was not secure and there were 2 screws in the bottom of the case lying around suggesting someone started to attempt to strip the unit. The stand off insulation board underneath was elsewhere in the machine so first thing I did was resecure this (although missing 2 screws until I find some more).

I cannot see any burnt out components, all I could see slightly a miss inside on a first inspection was that one of the bottoms of a caps looks like it has a fair bulge on it... not sure its normal but it is the only cap of its type in there so nothing to compare against. Usual caps i've seen that have gone tend to have bloated up and the tops look rounded off.

All I have done so far is diagnose the switches work on the torch and foot pedal.

I have attached pictures of the unit, most Super 200P pictures I see include a 2T/4T switch however this unit has a "Gas test/auto" switch in this position which appears to do nothing also. I guess I need to start looking for voltages and see what happens... if anyone has any tips on where to look it would be appreciated.

I noticed jakeru's posts regarding a diode-ectomy but it seems I do not have the same dual package diodes that were used in his. I have fast recovery diodes with part number "D92-02". I am unsure on how to test these for shorts whilst on the board... is it even possible? . I also think i'm having a different problem as others have the OC fault light on.












Best regards,
Lee

[poxxxy]