stichill99
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- 94
After fitting new fuses welder still does not spark. Lights up when switched on and wire feeds but will not spark. I have cleaned and checked the earth cable/clamp which is fine. Anybody got any ideas?
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Murex 235 Tradesmig Problem
- Thread starter stichill99
- Start date
stichill99
Member
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- 94
Any Ideas out there?
When you press the trigger on the MIG torch do you hear the gas solenoid open, and the main Contactor ( heavy duty relay ) "clunk" on?
The Contactor may have a manual-on push-button in the centre of the top. If so, try pressing that button ( e.g. with an insulated screwdriver ) and test if you can get an arc at the MIG tip.
The Contactor may have a manual-on push-button in the centre of the top. If so, try pressing that button ( e.g. with an insulated screwdriver ) and test if you can get an arc at the MIG tip.
stichill99
Member
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- 94
Hi Eddie I think it is silent. I will look tomorrow and see if I can see a button on contactor. Cheers
stichill99
Member
- Messages
- 94
The welder makes normal sound when starting,you can hear fan running . Reset button didn't work so I am still stuck.
If the wire feeds when you press the torch trigger, that means the auxiliary supply ( small 24v transformer ) is OK, and the PCB sees the trigger contacts closing, The gas solenoid should switch on - this may be audible, and the main Contactor should pull in - you would definitely hear this if it happens. If it is not pulling in, then either the power is not being sent to it from the PCB, or the operating coil on the Contactor has burnt out. There may be a label to show the coil voltage - 230v AC, or 24v DC. Check for that voltage across the coil when pressing the torch trigger. With the machine disconnected, use an Ohmmeter to check if the Contactor coil has gone open-circuit.
Even if the Contactor does not close when pressing the torch trigger, you should be able to close it manually with the button, and then you should get an arc at the torch tip ( with the machine on, trigger pressed, and the manual button held in ).
Even if the Contactor does not close when pressing the torch trigger, you should be able to close it manually with the button, and then you should get an arc at the torch tip ( with the machine on, trigger pressed, and the manual button held in ).
stichill99
Member
- Messages
- 94
Took welder to a local electrician and he fitted a new capacitor and all working again.
JohnHodgson
New Member
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- 5
- Location
- Carlisle
Does the main contractor bring in the gas solenoid?
Will try operating the contractor with an insulated screwdriver to see if what you say works.
If it’s a yes how do I replace or test the capacitor?
Will try operating the contractor with an insulated screwdriver to see if what you say works.
If it’s a yes how do I replace or test the capacitor?
There are Murex Tradesmig circuit diagrams here:
The diagram for the single-phase 245 shows that the solenoid coil of the gas valve is in parallel with the operating coil of the Contactor. When the electronics on the PCB tells the Contactor to pull in, the gas valve will also open.
However, on your machine it looks like the Contactor is not getting the signal to pull in, so to test what is going on, we can push it in manually. That will help to diagnose where the fault is. With the machine plugged in, switched on, the torch trigger squeezed, then the manual button on the Contactor held in with a screwdriver, you should get wirefeed running and an arc at the wire tip. I don't think the gas valve will open, but let us know if it does. This test will help to decide if it is the operating coil of the Contactor that is burnt out, or the electronics on the PCB.
This old thread from 2019 is for the 3-phase model 235, I think it would be clearer to continue this discussion in your new thread for the single-phase 245:
Your machine does have 6 large capacitors across the welding output, but the machine in this thread, the 235, does not have any. Being a 3-phase machine the output is already smoother, and does not need capacitors, so I don't understand the solution that was referred to in Nov. 2019.
The diagram for the single-phase 245 shows that the solenoid coil of the gas valve is in parallel with the operating coil of the Contactor. When the electronics on the PCB tells the Contactor to pull in, the gas valve will also open.
However, on your machine it looks like the Contactor is not getting the signal to pull in, so to test what is going on, we can push it in manually. That will help to diagnose where the fault is. With the machine plugged in, switched on, the torch trigger squeezed, then the manual button on the Contactor held in with a screwdriver, you should get wirefeed running and an arc at the wire tip. I don't think the gas valve will open, but let us know if it does. This test will help to decide if it is the operating coil of the Contactor that is burnt out, or the electronics on the PCB.
This old thread from 2019 is for the 3-phase model 235, I think it would be clearer to continue this discussion in your new thread for the single-phase 245:
Murex 245
I have a murex 245 single phase welder which is probably 30 years old. When I press the trigger the wire feeds but no gas or anything else happens. What do you think is the problem?
www.mig-welding.co.uk
Your machine does have 6 large capacitors across the welding output, but the machine in this thread, the 235, does not have any. Being a 3-phase machine the output is already smoother, and does not need capacitors, so I don't understand the solution that was referred to in Nov. 2019.
JohnHodgson
New Member
- Messages
- 5
- Location
- Carlisle
I have tried what you advised, with the contractor pressed in I have an arc at the weld tip,as you said the gas solenoid is not working!
What do you advise next,
Regards John
What do you advise next,
Regards John
This old thread is for the 3-phase Murex 235. I think we should continue discussing the problem with your single-phase 245 welder on your new thread:
I have posted an update there.
Murex 245
I have a murex 245 single phase welder which is probably 30 years old. When I press the trigger the wire feeds but no gas or anything else happens. What do you think is the problem?
www.mig-welding.co.uk
