okay mate ill have a look, and its all helpful, good on ya.
i have the manual specific to my machine, and i have seen the one for the 200amp machine, and your right it is more or less the same. i have tested the diode block D1 and it tested good according to the manual.
maybe old mate was right about " just buy a new welder". just got the quote back from the mob in japan who make that welder for a few different companies. $936 AUD
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Hi Jordan
Good, that is one thing out of the way. Testing OK would probably be expected. When a manufacturer puts a network such as these diodes in such a potted assembly the usually have one thing in mind. Reliability. The potting mix is a good conductor of heat to the outside world (the only exception is if the vacuum system leaves air bubbles in the mix, a pretty rare happening) and everything is as sealed from human intervention as much as possible.
It is obvious that this board has a problem as indicated by the overheated resistors and diodes. But the real problem will be down stream from here. There is a reason these components were over stressed and that bit has to be fixed as well as the bits on that board. This sort of thing usually is caused by that particular supply getting a short on its output. Shorted electrolytic caps are one cause but anything causing massive overcurrent will do this sort of thing. Unfortunately experience plays a significant part in tracking down this sort of thing and extremely difficult to do remotely as on this Forum. For instance did the damage occur while the welder was at rest or when welding. The only thing I can suggest would be to have a poke around with a multimeter with the welder unpowered looking for shorts on that particular supply. Then do it again with the board unplugged in case the problem is in fact on the board like shorted electrolytic. Here you can run into problems like electolytics looking like a short until they charge and the resistance ranges of a DMM only provides a low voltage which may not show up a problem.
But whatever you do DO NOT just plug in a replacement board and turn it on without providing adequate protection. If you do you could destroy a new board just as quick and be back to square one but a bit more out of pocket.
Unfortunately this is where experience comes in and you don’t get that in 5 minutes and it is very hard to communicate, especially remotely. I don’t think there is any way around this.
Of course you may have extensive experience in this sort of thing, I don’t know. If so carry on if you choose but I don’t think the warnings I have just outlined are out of place, experience or not.
Cheers Bob
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Yeah im not gonna spend a grand on a new board. Thats insane.
And nah mate what you said isnt out of place. Im not a complete dummy with these things but also well aware that my knowledge is limited with this.
Ill just try to find someone with the know how reguarding repairs, welder repair shops these days just seem to throw new boards at it untill it works again, getting it fixed at component level is the tricky part.
I appreciate your help anyway. Good on ya mate. Happy new year
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Hi Jordan
That says it all.
Labour costs are so expensive and components relatively cheap it is often not commercially viable to repair down to component level. You don’t get many hours for something like $500 these days.
I remember whenI I first came across something like a sync pulse generator in a Television system. Repaired down to faulty diode, capacitor, resistor and dare I say it Valves (or “tube” in US jargon). Fun days. Now you probably replace the whole generator with a couple of chips.
Even in later years labour costs were so high that before “proper” IC removal tools were commonly available the most economical method was to cut all the IC legs and remove them individually, then just replace the IC even if it was only suspect. This was far more economical than trying to pin down a suspect component.
That was in the commercial world and often the case in the hobby side of things too.
Cheers Bob
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Yeah ya dead right mate. These are the prices we pay when governments print monopoly money for 40 odd years. I appreciate your help anyway
