Welder's Just Died

[Guest timswait]

Was in the process of welding up my alternator bracket (yet again!) and my welder stopped working. it's a Clarke 150TE Turbo MIG. The fan runs and the mains light in the switch comes on when you turn it on, but when you press the button on the torch there is no wire feed and no arc . Any ideas on whats up with it or what to check. I'm fairly competent with electrics and understand the principle behind how a welder works, but I've taken the side off and it's a bit hard to trace where a fault might be. It happened immediately after changing the roll of wire if that's significant, ie was working before and not after!

[RedTrev]

Tim,

I've seen welders where the wire feed motor control circuit has gone kaput. It's normally the motor's speed control transistor or the (smaller) transistor that drives the base of this transistor, if you know what I mean

However, if, as you say , the arc has gone as well, it could be the hefty rectifiers (bolted to a heatsink) that may need attention. Have a look at the circuit board and use your senses... the nose is good at detecting a burnt out component if it's not obvious by sight!!

Good luck, and be careful if you're having a look inside when it's plugged in!

Trev

[Guest chris brown]

It sounds like the over temp switch has tripped (given up) as that does leave the fan running but cuts power to the transformer. It's a case of tracing the wiring to the transformer using a voltmeter. BTW if it is the over temp switch then just short it out until you can get another just remember not to do lots of work without frequent rests.

[Guest timswait]

Ah Ha!

Just found the problem (or at least another symptom!) There's a miniature 500mA fuse on the PCB which has blown. I'll get another from Maplins tomorrow and see if it cures it. Fingers crossed there's no other problems which caused the fuse to blow in the first place. Tested the thermal cut outs (there seem to be two), and they're reading no resistance (not cut out) and can't see any obvious signs of damage on the board or anywhere else.

Thanks for the ideas guys . Internet forums are amazing. I sent Clarke a query about this, but don't really expect a reply within the next couple of days. A couple of posts (I also put one on the MIG welding forum), and I get a flood of useful infomation, even at this time of the evening!

[Mat-Moo]

Funnily enough mine did the same aocuple of weeks ago. I was having a problem with the feed, and after pulling it all apart and giving it a good clean, ran great for about 5mins then poof, no feed at all now I'll have to open up and check fuses as well, but I think my motor has gone.

[Guest Guy]

My welder started playing up a few weeks back as well, it suddenly started giving poor quality with lots of splatter and no power. I took it all to bits and traced all the continuity back to the high/low power switch, which was set to low power I must have knocked it with the cable

 

So I switched it back to high power and all is fine now

[Guest timswait]

Couldn't be as simple as a blown fuse could it?

Put a new fuse on and it blew as soon as I turned the mains on (before even pressing the button). Put another new fuse in and this one didn't blow, but it still doesn't work. I'm pretty sure the problem is the miniature PCB mount transformer which supplies power for the board, it was reading an open circuit across the primary windings, probably shorted intenally blowing the fuse, before burning itself out. Taking it off confirms it, I can see one of the fine wires burnt out.

The problem is how do I know what to get to replace it? It doesn't say it's output voltage or current rating. All it says on top is SVTI 220-240, and underneath it says ZETTI GT 13 Y25.

There's a relay on the board which has 24V marked on it's windings, so I think it's most likely 24V.

[Grim]

wel, it could be anything up to 24v, 24v will be the max of the relay...

[Dave R]

got a picture of the welder itsself ?. if it looks the same as mine i will got looking with a voltmeter

pretty sure mines a clarke, but all the cheapo ones are similar

[Guest timswait]

I've ordered a 24V Transformer from RS of similar physical dimensions to the dead one, it's £5 as opposed to 50 for a new board. If it blows the board then I'll just have to get a new one, but it seemed worth trying before I buy a new one. Dave: Here's a photo, but it's a bit fiddly to get to the other side of the board to measure, so I don't blame you if you don't want to dimantle yours to find out!

[Guest timswait]

It's fixed!!!

Got a new transformer (24V) from RS, had to modify the board a little to get it to fit and now it works again! Was half expecting a little puff of smoke and that sickening smell of burning silicon from one of the transistors when I turned it on, but no, it just works. Cost about a tenner as opposed to fifty for a new board. Incidentally Clarke turned out to be pretty helpful when I contacted them by email, even if they couldn't tell me what voltage the board ran at.

[Dave R]

glad it works,

i had forgotten to look at mine till last night, didnt have time or the inclination to attempt it when i look as to what was involved!!

 

[Guest Battery Bill]

Guy

 

started giving poor quality with lots of splatter and no power.

 

Sounds like Chris Browns welding

[Guest chris brown]

Guy

Sounds like Chris Browns welding

 

very funny well it would be if it wasn’t true about some I’ve done using a very old and cheap welder that sometimes supplies gas sometimes feeds wire at a constant rate and sometimes gives full power but rarely all at the same time.

[Guest wallsy]

do you have the part number for the transformer? think mine is gone also

 

cheers