- Thread starter Jaffman
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hotponyshoes
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I can't get the video to work?
First thing I would do with an HF problem is check the leads (both of them)
Got a spare torch you can try?
First thing I would do with an HF problem is check the leads (both of them)
Got a spare torch you can try?
It should be a YouTube video?
It is unlisted but as long as you click through it should work.
I don’t think it’s HF as the HF works on the DC side
I don’t have any spare leads unfortunately
hotponyshoes
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I'm only suggesting to start with the HF as that's the only problem I've ever seen with ewm tigs and that's been due to the leads on both occasions
I'll try the video again when I have a better connection.
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There has been a ridiculous amount of condensation recently so if this is a new.problem, I'd take the machine into the house and get the covers off for a look
I’ve opened the machine up but it’s too tightly packed to get a good look at it. I have however found some indication of failure on an IC on the board at the top of the machine l…
Any thoughts on where else to go if this bit isnt that important?
I can’t find any loose cables or plugs.
One thing to note is it did happen after I had moved the machine around a bit as I was rejigging the cart that is sits on. But that might be a red herring
Any thoughts on where else to go if this bit isnt that important?
I can’t find any loose cables or plugs.
One thing to note is it did happen after I had moved the machine around a bit as I was rejigging the cart that is sits on. But that might be a red herring
From what I can see that chip reads UC370 something on the top row, with the last digit burnt away. The UC370x series are a range of high speed, high power drivers so I suspect that is driving something very important!
A picture from a working machine or a circuit diagram would probably be needed for confirmation of the full number. Whether that's let out the magic smoke on its own or has been damaged by something else is difficult to say but I don't think moving the unit around has caused it if there are no loose cables or plugs.
A picture from a working machine or a circuit diagram would probably be needed for confirmation of the full number. Whether that's let out the magic smoke on its own or has been damaged by something else is difficult to say but I don't think moving the unit around has caused it if there are no loose cables or plugs.
Yeah Ive managed to take one side board off an it looks clean, no stains.
From what I can see of the other board it’s pretty clean too but I don’t want to take that one off as it has some seal to the heat sinks which I assume would have some gunk between it for heat transfer that I am unable to replace.
You’re right it’s UC37 something something N, and that pin that has blown goes via the back of the board through maybe a resistor to another pin on the chip.
I guess this will require a new board and then it’s a risk that it goes again? Although I’m not against giving it a go and replacing this single chip
I’m trying to think back, I was welding something small and aluminium for a bike when it gave way and stopped working so it could well have just given up the ghost as it was being used
From what I can see of the other board it’s pretty clean too but I don’t want to take that one off as it has some seal to the heat sinks which I assume would have some gunk between it for heat transfer that I am unable to replace.
You’re right it’s UC37 something something N, and that pin that has blown goes via the back of the board through maybe a resistor to another pin on the chip.
I guess this will require a new board and then it’s a risk that it goes again? Although I’m not against giving it a go and replacing this single chip
I’m trying to think back, I was welding something small and aluminium for a bike when it gave way and stopped working so it could well have just given up the ghost as it was being used
Pin number 6 which has fried seems to be “logic ground”
Which is all a little bit beyond me now without any wiring diagrams.
Worth trying to change it?
Can’t break it anymore than it’s already broken can I?
So if I totally beans it up it’s a new board required anyway
Which is all a little bit beyond me now without any wiring diagrams.
Worth trying to change it?
Can’t break it anymore than it’s already broken can I?
So if I totally beans it up it’s a new board required anyway
sako243
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Yup take some small side snips to the pins and cut each leg off it then desolder them individually. Much easier that way since it's kaput.
Any idea on how to work out what it’s supposed to be?
The 05 seems to be the most common one but the internet can be quite unreliable these days
This chip is a driver for high-power MOSFETs. If those transistors fail and short-circuit internally they can conduct their high-voltage supplies ( 325v DC ) back down the Gate circuit and destroy the driver. The extent of the damage to the chip and the fact that it was at the Ground pin implies that maybe the MOSFET connected to the output of this chip - Pin 4 - has failed. I would suggest tracing where that output goes - probably off this board and on a heatsink somewhere.
The driver is the board attached to the heat sinks?
I assume I’d need some thermo paste to reattach this? Removing that board makes me a little nervous considering the semi permanent fitment
The MOSFETs will be at the other end of the grey ribbon cable that plugs in adjacent to the UC3708, follow that and see where it goes. It might go to another board or it might go direct to MOSFETs sat on a heatsink somewhere. If it does go to the board attached to the heatsink then yes really you should pop some new thermo paste on there for reassembly. Have you got / can you get a decent pic of the heatsink board?
