garyo
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| posted on 3/10/09 at 04:01 PM |
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Clarke welder - packed up
My Clarke 130 I Mk2 has died. It's was working perfectly in the morning, then I switched it on four hours later and it's completely
unresponsive when the trigger is pressed.
I've taken it apart, wiggled everything, and checked the trigger terminals inside with a multimeter, and that seems fine. There's not so
much as a relay click when the trigger is pressed. The green light is illuminated though, so it has power.
Is it worth trying to get it fixed? It's probably ten years old but has had very light use. I see there's a circuit board in there -
worth trying to replace it? Or do they have any common failure points?
Cheers
Gary
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suparuss
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| posted on 3/10/09 at 04:14 PM |
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as it got a series of switches for power selection liek the sip welders? they can sometimes get balanced half way between open and closed and cause a
zero response situation.
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Danozeman
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| posted on 3/10/09 at 04:23 PM |
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Is there power at the torch? theyr only connected with spade ternimals?
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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Rod Ends
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| posted on 3/10/09 at 04:28 PM |
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Clarke MIG manuals
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MkII
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| posted on 3/10/09 at 04:28 PM |
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most welders have a fuse to protect the circuit board if it has blown it would cause the problem you have,also the circuit board and torch will be fed
at low voltage from a transformer,these have also been known to fail. hth. m.
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Mark Allanson
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| posted on 3/10/09 at 05:11 PM |
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I have a Clarke 140 E, bought new in 1988 and used professionally for 12 years. It has gone throught 2 torch microswitches - they are the standard
ones you can buy at any electrical appliance repairers.
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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02GF74
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| posted on 3/10/09 at 06:58 PM |
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check that the wires are connected.
mine would click and that was it - turned out the connectors crimped onto the wires for the motors was different to the tags on the nmotor so had
fallen off.
it could be the relay that has gone - the connector in the torch, on mine at least, was a springy piece of steel against the brass gas vavle block -
sounds like you have checked out the torch switch.
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MikeRJ
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| posted on 3/10/09 at 07:35 PM |
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By a strange coincidence my Clarke 150TE packed up today. The problem tuned out to be the thermal switch mounted on the rectifier had gone open
circuit, not though high temperatures (had only just switched it on) but I suspect due oxidisation of the contacts internally. A few quick taps with
a screwdriver handle and it burst into life.
Don't trust the schematics given in the Clarke manuals too much, the wiring for both my current 150TE and my previous 105 bore only a passing
resemblance to what was printed in the manual.
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garyo
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| posted on 3/10/09 at 07:53 PM |
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Thanks for the replies.
It does seem like something like thermal cut out or relay failure. I could believe that some contacts somewhere might have oxidised given the state of
the transformer too.
So, I'll try to identify the thermal cut out switch tomorrow - is it on the main transformer? (and I'm off to read some of the clarke
manuals to get some hints!)
Gary
[Edited on 3/10/09 by garyo]
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mark chandler
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| posted on 3/10/09 at 08:33 PM |
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Mine went wrong a few times, must be 20 years old now.
Anyway tracks burnt on the board so bridged with wires.
Diodes on the rectifier blades went so stuck on much bigger ones, cost a couple of quid.
Fan went, so used a equipment fan instead.
They are very robust.
Regards Mark
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NigeEss
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| posted on 3/10/09 at 11:47 PM |
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Ooh.. I like this thread, obviously some welder-fixers here.
I've also got a 120E that's over 20 years old and has recently started losing power.
Used to do 3mm plate on max with wire speed on 7, now doesn't penetrate and
wire speed down to 4.
No burnig smells normally associated with transformer failure and no signs of poor
connections.
Any ideas ? And sorry for the thread hijack 
Time is an illusion. Lunchtime doubly so.................Douglas Adams.
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garyo
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| posted on 4/10/09 at 10:21 AM |
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I've tested both thermal cutouts and they're working fine - both closed circuit.
I've removed the circuit board, no obvious signs of blown components or burnt out tracks.
There's a large relay on the board which isn't switching when I press the trigger. The relay switches two separate circuits, and when I
manually close these I get 1) the gas valve clicking 2) the transformer 'hum'
When I press the trigger, no voltage is present on the coil side of this relay. It seems to be fed by another large black box which has an IC next to
it and probably associated with the wire feed speed control. I'll continue prodding, but suspect the problem is on the circuit board.
Gary
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garyo
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| posted on 20/10/09 at 05:55 PM |
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So, I've pulled the cover off the boards supply transformer, which is a 240 to 25v transformer. It looks as though the primary winding has
burned out - black marks on the PCB etc (see pic here: tranformer close up)
This seems to be confirmed by the multimeter reading open circuit over the primary winding. When the welder's powered up there's 240v on
the primary winding, and 0v coming out of the secondard.
So, I want to try a new transformer. Google hasn't turned up much on the part number, but it's labelled 240v 220v 0v on the input (with a
jumper to select between 240/220) and 0v 25v on the output. Presumably it's 25v AC output, so can I give one of these a go:
Maplin 240v/25v 6VA transformer
How can I get a rough VA rating for the existing transformer?
Oh - Clarke seem to want around £50 for a replacement board, which I'm reluctant to pay for a ten year old Clarke130, so I'd like to try
to replace the transformer.
Also (last question) Is it likely that the transformer is root cause and not a symptom of a fault elsewhere... I mean - do they have a lifetime and
just tend to go pop of their own accord as the insulation on the windings break down?
Cheers!
Gary
[Edited on 20/10/09 by garyo]
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MikeRJ
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| posted on 20/10/09 at 06:49 PM |
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6VA sounds too small for the job to be honest, that's only about 1/4 Amp secondary current. This transformer powers the wire feed motor ( as
well as the big relay and the gas solenoid if yours has one) and I'd expect it to take quite a bit more than that.
Personally I think the original transformer on mine is on the small side for the job it's doing, but I guess the typically low duty cycle of
hobby welders is in their favour.
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garyo
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| posted on 20/10/09 at 07:14 PM |
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Cheers Mike. Yep it has the big relay and gas solenoid.
Rapidonline seem to have a much bigger range than maplins, so the choices are:
CHASSIS TRANSFORMER 230V 20VA 24V+24V RC 88-3436 £5.21
CHASSIS TRANSFORMER 230V 50VA 24V+24V RC 88-3444 £7.94
I'm not sure if the 50VA rating on the latter one assumes I wire both output windings in parallel... but it seems pretty beefy compared to the
6VA and only £7.94. Any idea what the 'RC' in the name means?
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JoelP
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| posted on 20/10/09 at 08:17 PM |
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a guess at rectified?
must say i have no idea if you want ac or dc output anyway... IIRC you need ac for ally so id guess your mig will be dc output, but im sure someone
will clarify soon.
[Edited on 20/10/09 by JoelP]
Beware! Bourettes is binfectious.
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garyo
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| posted on 20/10/09 at 08:42 PM |
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Mmm good point. This isn't the huge transformer that actually does the welding business - it's the small one on the PCB that powers the
speed controller hardware for the wire feed motor and powers the gas solenoid valve.
I think I'll desolder the transformer off the board and look for some rectifier gubbins inside. (Edited to say - but surely it's either
DC or there'd have to be something else on the board to provide DC for the solenoid?)
[Edited on 20/10/09 by garyo]
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Peteff
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| posted on 20/10/09 at 10:23 PM |
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AC is for tig on aluminium, mig is DC for anything.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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garyo
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| posted on 29/10/09 at 09:00 PM |
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The welder's fixed. The £8 transformer, costing £15 with vat and delivery, did the trick.
It's three times the size of the one it replaces so is bolted to the chassis rather than the PCB.
Cheers for the help guys.
Gary
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robocog
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| posted on 15/10/17 at 01:20 PM |
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Pinging a VERY old thread I know, but mine has suffered the same fate
No primary continuity on the wee little transformer on the circuit board - so no 24v output and nothing happens (apart from mains light on switch)
Looking at mine - the gas solenoid is 240v, so the 24v transformer is only for the circuit board and driving the motor and operating the relay that
fires the big transformers - so not a massive current required
(tested by manually closing the relay via an insulated screwdriver at arms distance - the transformers fire up and the gas solenoid opens)
Which size did you go for in the end (kva rating)? and where from (did you get one from Rapid?)
About to try and desolder the transformer and see what I can find to make my welder work again
(put it away working some 5 or 6 years ago and it hasn't even been moved)
Regards
Rob
Edited minutes later
Transformer removed very smoothly and cleanly (good old lead solder!)
Spotted the issue as soon as I turned the transformer over and removed the plastic base - one of the magnet wires had come adrift of the peg on the
primary
No sign of burnback or anything untoward
Managed to solder a few mm of wire to the end and re join it to the base
Possibly only a temp fix (so no manhandling of welder!)
Tested it just now - back to being a working welder
Still interested in which transformer you went for - as I am sure mine will not last that long - did think about gluing the leg so it is mechanically
supported back into the rest of the coil, but maybe just replacing the transformer is the sensible thing to do
[Edited on 15/10/17 by robocog]
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