clarke 100E broken

[.aj.]

Hi all

i recently got a clarke 100E mark 2 that was broken with the plan to have some fun fixing it. the problem is that nothing happens when you pull the trigger, there is gas but no wire feed. im wondering if anyone can help me with trouble shooting?

what i have looked at so far:

there is no obvious burnt components on the p.c. board and doesn't look like there are any gaps where there shouldn't be on the foil bit of the board.

the relay doesn't switch when you pull the trigger, if you manually switch the relay the wire feed works fine and it welds as normal.

measured the resistance and voltage across the coil of the relay and there is a small resistance so would guess its not burnt out and there is no voltage with the trigger pressed or not.

i also measured the resistance across the two sides of the switch in the torch and got very confused as there was one, about 102 ohms, but guessing it should be like that as i would expect it to be less if it was shorting inside the cable.

if people have any ideas for things i should check it would be much appreciated.

and iv added a picture as it just wouldn't be the same without it

cheers
Aj

 

[craig8661]

hi there you say you took a res of the switch did you unplug it to test direct you will have open res with switch not pressed then direct short pressed if the switch is ok unplug cable both ends and do a test up each lead to switch to make sure its ok that there is no high or open res. it could be a diode on the bord or even the transister can you tell me where your trigger wires are on the board and what coulor by the looks of it its the top right plug and the one red and black is it or are they feeds for the welding

 

[Jake SS]

Firstly chase the trigger wires back and meter them with trigger closed, should be between 0 and 2 ohms, (machine off)
the small transformer on the PCB, think it will be 240v in and about 12 to 15v out
Use extreme caution when doing this
If you dont feel confident then do not do any live testing !!!!

 

[.aj.]

the resistance i took of the switch i think i took when plugged in but have checked and its the same with the power on or off, on the up side it does go down to zero when you press the switch so common sense isnt completely lost. the wires for the connector on the top right are:
brown for one side of the switch
black next to the brown is connected to the metal plate thing (technical term )
the black next to the red goes to the motor
red next to black also goes to the motor
and the last red is to the other side of the metal plate thing that is also connected to the thick power cable running up to the torch.

on the transformer front on the back of the pcb there is 24V and E1285.3 written but it has 75V in and 3V out.

 

[R Kraft]

They seem lately, to tend to burn out the PCB transformers.
Robert

 

[peterd51]

Hi,

I had a Pro90 some years ago and that burnt out the motor feed transformer. I replaced it with a 'general purpose' 240 to 24v transformer and everything worked again. But didn't you write earlier that the motor turns if you operate the relay by hand?

In that case it looks like you'll need to trace the wiring, maybe draw a diagram (it isn't tricky). Simply start with one motor wire and trace it through, drawing in each component and finish at the other motor wire, all in one line on the drawing. You could tidy it up if you wanted into a 'standard' type of diagram but a single line would be enough to show you what's happening.

A trick for tracing across a circuit board is to use a fine tipped marker pen and put spots along the track at regular intervals, it shows where you've already checked.

You could then check individual components like the diodes (high resistance with the leads one way around, low resistance when you switch the leads over) and transistors (test as if it's two diodes back to back).

Finally check all of the resistors. There'll be a component blown somewhere, or possibly one of those connections that you mention as they look like punch-down crimps.

Regards
Peter

 

[Jake SS]

check back to where the feed comes in to the auxiliary transformer,
check the PCB and spade terminals for bad soldered joints, use a magnifying glass, resolder any crook joints

 

[.aj.]

sadly does not look like there are any cracked joints
i have had a look at the resistance of the components and there are no shocks and dont think any of the small components have gone. im not sure if any of the active components have gone.
im thinking trying out a new transformer might be a good idea.

 

[R Kraft]

The transformer on most of the small welders, is just for operating the PCB relay.
It should take 240vac in and drop it to 18-24vac out.
You would need at most a 500ma transformer.

Robert

 

[.aj.]

awsum thanks will find one and let people know what happens

aj

 

[M1CDQ]

you might even have whats know as a dry joint on one of the components
it looks like its soldered ok but it will be an open circuit.As with most electric circuits dont touch unles you know what your doing.Capacitors have a tendancy to give you one hell of a kick and put you in a wooden box.

if you use a multi meter across the trigger switch set on volts.With the trigger switch unpressed you should get a voltage wiht it pressed you should get zero volts

 

[acc80]

Hi Jake i have clarke 100e mk gas mig welder and had burnt out on the torch trigger connection, however I did not have wire fitted from this I cannot power it on and belive I might have blown the internal fuse , I have checked for burn damage internally but cannot see any damage , any help please would up load photo but site does not seem upload them

 

[OJCar]

2009 to 2025... One of the better thread Resurrections

 

[eddie49]

I don't think you will get a reply from Jake. He was last seen here 14 years ago.
With most of the small MIG welders you start at the small relay on the control board. When you squeeze the torch trigger, you should hear the relay click and, if transparent, see it move inside. That should power-up the arc and start the wire moving.
If this does not happen, try to remove the plastic cover and then actuate the relay manually, using an insulated screwdriver.

 

[bourbon]

2009 to 2025... One of the better thread Resurrections

maybe useful for someone. I wasn't working for the place that long ago

 

[acc80]

Thanks