Transmig 180 pc board

[Bluestone72]

Hi Team.
Does anybody know where I can get a replacement pc board for my welder.
It's dead. I've had it repaired as best as the electronics guy can do but still can't get anything out of it.
Wire feed motor etc all seems to check out ok.

 

[eddie49]

Hello and welcome to the Forum !

This earlier thread has a copy of the manual attached to Post #4:

Cigweld 180 wire feed

Cig weld 180 brumby. Wire feed motor has stopped working. Was working fine, gave the machine a long overdue blow out now no wire feed. All other aspects seem to be fine. Still arked, fan, switching from trigger just no feed motor. Any help would be appreciated.

www.mig-welding.co.uk

and there are circuit diagrams of the welder and the PCB in there.
This thread refers to a different version of the board:

Cigweld transmig 180 se

Hi , just bought a transmig 180se , here in oz , works fine ,came with a large wire reel and gauge 350$ , the price of a new chinese one ! , the bloke had it sitting in his shed with minimal usage for years , has a newlinner/gun aswell , can anybody tell me roughly how old it is and how good or...

www.mig-welding.co.uk

Which version do you have, and what are the faults that you are seeing - i.e. failing arc, gas valve, or wirefeed, or all three?

If your board does not correspond to that circuit diagram, then if you could post photos of both sides of your board, and identify what external components connect to which connector pins, it may be possible to reverse-engineer enough of the circuit to suggest which components may be causing the problems, and what measurements to take for further diagnosis.

 

[Bluestone72]

Thanks Eddie.
Attached photo of model details

 

[eddie49]

The initial difference between the two versions of the board is that the one described in the manual, with circuit diagrams for the welder and for the board itself, has two 4-pin connectors and one 6-pin connector - but that does not correspond to the actual photos in that thread. The second thread linked above also has a similar photo of a board with three 4-pin connectors. If yours is like that second version, then unfortunately the diagrams do not apply - but they might be similar.

 

[Bluestone72]

The initial difference between the two versions of the board is that the one described in the manual, with circuit diagrams for the welder and for the board itself, has two 4-pin connectors and one 6-pin connector - but that does not correspond to the actual photos in that thread. The second thread linked above also has a similar photo of a board with three 4-pin connectors. If yours is like that second version, then unfortunately the diagrams do not apply - but they might be similar.

Hi Eddie
Yeah mine pc board has 3x4 pin connectors but it may still be helpful for the electronics guys.
Don't want to dump it as it's a great welder and in NZ is round $ 2500 to replace.
Can't spring that far just for intermittent use at home.

 

[eddie49]

When you squeeze the torch trigger, three things should happen:
1 - wirefeed motor starts
2 - contactor ( heavy-duty relay ) closes, powering-up the main transformer
3 - gas valve closes.
The wirefeed motor should run and feed wire, you should be able to hear the contactor close with a loud clunk, and maybe hear or feel the solenoid of the gas valve moving. Which, if any, of these three things happen? When we know that, we can start to focus the troubleshooting steps.

 

[Bluestone72]

When you squeeze the torch trigger, three things should happen:
1 - wirefeed motor starts
2 - contactor ( heavy-duty relay ) closes, powering-up the main transformer
3 - gas valve closes.
The wirefeed motor should run and feed wire, you should be able to hear the contactor close with a loud clunk, and maybe hear or feel the solenoid of the gas valve moving. Which, if any, of these three things happen? When we know that, we can start to focus the troubleshooting steps.

Hi Eddie.
None of those happen unfortunately

 

[eddie49]

If nothing works when the torch trigger switch is pressed, then the first thing I would suspect is the auxiliary power source - which should be providing power for the logic on the PCB, ready to start the welder functions.

According to the overall circuit diagram on Page 20 of the CIGWELD manual linked above, there are a couple of power sources. One is the fairly standard small transformer providing 24v AC. You need to find that transformer and verify the output.
The other source is a strange one, where a second winding on the fan motor effectively uses it as a transformer! Please check that the fan is running when the welder's main power switch is on, and check for an AC output across that "secondary". Mains power is supplied to the fan on two brown wires, and the output should be on two white wires.
Both these AC sources connect to the PCB, and I assume they are rectified there. After verifying the two AC sources, if you could post photos of both sides of your board, and identify which connector pins join to those two sources, it should be possible to trace the tracks and locate the rectifiers and smoothing capacitors on the board. The diagram for that version of the PCB shows the "fan-derived" AC connecting at Pins 1 & 2 of socket X1, and the 24v AC supply from the small transformer at Pins 5 & 6 of socket X3.

Another thing to check is the two overtemp thermal cutouts. There is one on the main transformer and one on the large rectifier. They should be closed circuits with zero resistance across the two terminals. If in any doubt, just short across them.

Does the contactor ( large heavy-duty relay ) have a manual operating button? If so, power-up the welder and press that button. This should send AC mains power to the main welding transformer. Check if that allows you to strike an arc at the tip of the MIG wire. There are live mains cables at the contactor terminals, so use an insulated screwdriver to press the button.

 

[Bluestone72]

Great and thanks Eddie.
I'll get my mate to check that out as he's the electrical engineer.

 

[Relic]

Good diagnosis Eddie.
Had a slightly larger cigweld headache recently.
Weld spatter got to wire feeder board smd chips.
Fan used as an auto transformer.
Cheap manufacturer.