the snooper
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no certainly not worth powering up, as its down on power now something has gone probably a diode maybe more then one, so it wont be just conductive dust causing it
- Thread starter mattylandrover
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the snooper
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looks like there are 16 diodes on that rectifier £££££ scary 
mattylandrover
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workshopchris - ive just had a look at where you say the insulation looks burnt and the copper windings are a blackish colour - is this normal from a well used welder or a sign something has gone wrong
the snooper
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they can become dark depends what colour lacquer and dirt is on them, as we have found signs on the rectifier that is your most likely cause, transformers that are burning out usually blow the mains fuse
mattylandrover
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yes 16 diodes i see what your looking at now - if this is the cause how expensive is it likely to be to get it repaired
mattylandrover
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ive just gone to start cleaning it out and found that one of the legs going to the diode has snapped off - the solder had melted so im guessing thats what the spark was . So now im guessing i need a new rectifier ? or can anyone repair the old one ? .
Is there any other component inside the welder that may have caused this to happen as obviously i dont want to splash out on a new rectifier for it just to do the same thing to that one.
Just want to say a huge thanks for all your help so far and there is no way i would have found the broke diode without being steered in the right direction .
Is there any other component inside the welder that may have caused this to happen as obviously i dont want to splash out on a new rectifier for it just to do the same thing to that one.
Just want to say a huge thanks for all your help so far and there is no way i would have found the broke diode without being steered in the right direction .
500e
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As said give it a good clean air line & ling bristle soft paint brush, & then do it again, if one diode is gone I would expect others to be suspect.
In pic4 the red insulation looks suspect as well by the eye terminal
In pic4 the red insulation looks suspect as well by the eye terminal
the snooper
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Have a look on that snapped bracket for signs of burning if it has any it could be the cause and you may be able to re connect the diode but I would get hold of a multimeter and test them all first
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mattylandrover
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ive give it a good clean out and i cant see any signs of burning on the bit that snaped off or the diode or any of the diodes . i do have a multi-meter so im guessing the next stage is to remove the rectifier to test all the diodes ? before i start i notice inside the welder there are 2 big blue what i assume are capacitors - if so are they likely to hold any sort of dangerous voltage that i need to release first?
the snooper
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the capacitors should be dead after 24 hours doing nothing
mattylandrover
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righty ho well it was last pluged in late yesterday evening so i will give it a few more hours to be safe so no doubt ill be back to pick your brains later on
the snooper
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just put a screw driver across them it will discharge anything left in them
mattylandrover
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just done that thanks - the capacitors must still be good even if the rest is knackerd lol got a hell of a spark/crack from them
the snooper
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Good job you didn't grab them then
mattylandrover
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right - ive removed the rectifier and split it - i can see my multimeter has a diode symbol but over than that im not realy sure how to test them - are the diodes pressed into the alloy casing and do i need to remove them or can i test them as they are 4 at a time . On closer inspection it does look like the one that snapped off has got hot .
WorkshopChris
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I only have a few seconds at the moment but basicly on either your diode setting or resistance setting, you should get a reading in one direction only with the diode. Measure one way round then the other. then compared between them if good should all read the same.
Hopefully someone else will be along soon.
PS. welcome to the forum.
Hopefully someone else will be along soon.
PS. welcome to the forum.
mattylandrover
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I think im getting somewhere - because they are soldered together in banks of 4 i have checked them 4 at a time and im getting readings between 0.452 and 0.475 and when checked the opposite way no reading (OL) . I then checked the last diode on its own (the one that had snapped the leg off and either way the multimeter comes up 0.000 so im guessing its just that one thats ********
mattylandrover
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are they soldered at the botom too - if so is it just a case of heating it up from other side
the snooper
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So just 1 I think they will be pressed in as you can't solder to aluminium
