Plasma argon TSE225 AC DC Tig repair

[JOEPRO]

This is a new Chinese AC DC Tig welder which kindly offered foc by @BrokenBiker on the forum. There is therefore no warranty etc. Having had success repairing a couple of welders before I received this one today.

It is as described in that it powers up OK and arc works fine. Welds happily.

But when in TIG mode the display looks OK and goes through all the settings OK but does not respond to the Tig torch button at all. No gas no clicking no nothing. It did work and tig weld OK then stopped with po.

I tested the tig torch and button and it works OK. I get continuity right up to the plug on the top circuit board of the welder from the torch terminals.

Please see some quick and not great photos of the internals below:



Visual examination doesn't show any obvious issues.

Where to go from here? I am thinking to keep tracing the torch switch circuit and see where it takes me on the board. Maybe also check continuity with all the various plugs to the circuit boards incase one is loose. I'm betting i can't get a circuit diagram but also that any parts on this welder are likely to be cheap and generic so if I can find the issue then I could get the parts.

Pardon our interruption...

 

[BrokenBiker]

This is a new Chinese AC DC Tig welder which kindly offered foc by @BrokenBiker on the forum. There is therefore no warranty etc. Having had success repairing a couple of welders before I received this one today.

It is as described in that it powers up OK and arc works fine. Welds happily.

But when in TIG mode the display looks OK and goes through all the settings OK but does not respond to the Tig torch button at all. No gas no clicking no nothing. It did work and tig weld OK then stopped with po.

I tested the tig torch and button and it works OK. I get continuity right up to the plug on the top circuit board of the welder from the torch terminals.

Please see some quick and not great photos of the internals below:

View attachment 482576View attachment 482577View attachment 482578View attachment 482579View attachment 482580

Visual examination doesn't show any obvious issues.

Where to go from here? I am thinking to keep tracing the torch switch circuit and see where it takes me on the board. Maybe also check continuity with all the various plugs to the circuit boards incase one is loose. I'm betting i can't get a circuit diagram but also that any parts on this welder are likely to be cheap and generic so if I can find the issue then I could get the parts.

Pardon our interruption...

Thats it...no returns now

 

[voipio]

What does "stopped with po" mean?

 

[JOEPRO]

What does "stopped with po" mean?

Po means previous owner.

So I was describing that it did work until recently.

 

[BrokenBiker]

Just a thought, and I did mention it in a previous post regarding that welder, possibly on my first tig welds thread, but the last time it worked, I was running around 180 amps on DC...obviously a wp17 torch isn't going to like that too much so it got hot pretty quick and I did notice faint smoke coming out the cup...I assumed I had just started to cook the torch so shut it off and let it all cool...that's the last time the tig function worked.

That said the wp17f I have put on this hit box will happily sit at 200 amps for a 3x 150mm welds on AC so I'm starting to think it wasn't the torch cooking itself but I don't know what could cause smoke in the gas system

 

[eddie49]

It is odd that the fault is in a low-power control circuit, rather than the more fragile high-power inverter components that usually fail on these machines.
I would start by unplugging and re-seating every plug on the inter-board wiring harnesses and flat cables. Then, as you said, continue tracing the circuit from the TIG button across the top circuit board. It won't be long before you run into a low-power integrated circuit. Note the type number, and check the soldering.

 

[JOEPRO]

It is odd that the fault is in a low-power control circuit, rather than the more fragile high-power inverter components that usually fail on these machines.
I would start by unplugging and re-seating every plug on the inter-board wiring harnesses and flat cables. Then, as you said, continue tracing the circuit from the TIG button across the top circuit board. It won't be long before you run into a low-power integrated circuit. Note the type number, and check the soldering.

Great suggestion Eddie - it's working again!!

I removed all plugs in the red circle below:



I then sprayed the plugs and sockets with electrical contact cleaner and blew them out. I also noticed there were fine metal (grinding?) particles on the boards. Very fine but it was there. I also noted one of the sockets had flux staining in it.

Maybe the flux caused the delayed bad connection.

I then tried it and it worked! HF start and DC welding test working.

My tungsten is old and dirty so I'm going to look out new fresh consumables to fit and try again later.

Fingers crossed it keeps working at this point.... that bit remains to be seen but very good progress all the same.

 

[JOEPRO]

Well this is bizarre!

There are times when it happily welds away on and off in DC and AC modes. Quite nice to use actually. Hf start working flawless.

Then there are other times when it will start the HF spark, but stay low on the workpiece. Not welding but a small stable arc. Then it won't stop with the trigger released. When you pull the torch away it then sits arcing on its internal HF points continously with the buttons not responding at all until you turn it off at the wall and go again. When it might do the same thing or work perfect again.

I think I'll disconnect and clean more plugs inside the machine as thoroughly as I can. I only cleaned the top plugs but there are more in there on the control panel and bottom circuit board.

How long should it sit to self discharge before I carry out this deep clean with relative safety!?

Anyway it's working now to some degree so hopefully with more time and cleaning it will come around fully to working reliably. To be fair to it, it welds really nicely in AC mode. As nice as my £1k SIP.

 

[JOEPRO]

Trying to show the metal contamination inside the machine as best I can:

Front inside:



Back inside:



The circuit boards are coated with this.

That could be part of the problems here too I suspect. Some sort of interference going on at times.

If problems persist beyond that cleaning I may also re flow the solder on those plugs I cleaned today.

 

[eddie49]

I think I'll disconnect and clean more plugs inside the machine as thoroughly as I can.

How long should it sit to self discharge before I carry out this deep clean with relative safety!?

I suppose that the moment you switch off, the power transistors stop conducting and so the charge from the 1,000-odd microFarads of capacitors is no longer getting fed into the primary of the inverter transformer. There will be some leakage, and auxiliary power supply board(s) will also help to drain the charge.
If you can locate the input bridge rectifier(s), which is across the mains feed and possibly after a mains filter circuit, you could monitor the 325v DC there, and watch it fade away. A 1k Ohm 5 Watt resistor with insulated croc clips could be used to speed up the process.

I would be tempted to wash all that dust off, and also use a pointed probe or small screwdriver to tighten up the female sockets of all the Molex-type plugs.

 

[JOEPRO]

I suppose that the moment you switch off, the power transistors stop conducting and so the charge from the 1,000-odd microFarads of capacitors is no longer getting fed into the primary of the inverter transformer. There will be some leakage, and auxiliary power supply board(s) will also help to drain the charge.
If you can locate the input bridge rectifier(s), which is across the mains feed and possibly after a mains filter circuit, you could monitor the 325v DC there, and watch it fade away. A 1k Ohm 5 Watt resistor with insulated croc clips could be used to speed up the process.

I would be tempted to wash all that dust off, and also use a pointed probe or small screwdriver to tighten up the female sockets of all the Molex-type plugs.

If I left it unplugged for say 24 hours before cleaning it carefully should thay be enough for it to return to safe levels?

Yes I'll also see if I can tighten the female plug connections a little too certainly can't hurt.

 

[eddie49]

I'd say that waiting a few hours should be enough for the caps to discharge by leakage.
A couple of 230v 100W filament bulbs in series could also be used instead of a bleed resistor.

 

[JOEPRO]

I cleaned the whole welder out tonight. Air compressor blast, spray with contact cleaner and blow that off right away. Appears to have done a good job.

I also remove the other 10 or so remaining plugs and cleaned them. I see a second one had some traces of yellow flux in there.

I opted to put the cover back on and take the welder indoors overnight where it's a little warmer to help dissipate all traces of the contact cleaner solvent before testing it again.

Re the molex female terminals, they are so small there is no practical way to try and tighten them. It would likely result in damage so I left them alone for now. Ideally a good clean and cleaning and re seating of all plugs will be enough to make it work reliably.

 

[Misterg]

I think I'll disconnect and clean more plugs inside the machine as thoroughly as I can. I only cleaned the top plugs but there are more in there on the control panel and bottom circuit board.

Check the solder on the header pins on the boards (where the plugs fit) for cracks/bad joints if you have them out. Might be worth re-flowing them all as a precaution (unless the boards are lathered in conformal coating or similar goop).

 

[JOEPRO]

After visual inspections failed to show anything the no response to the TIG torch trigger fault returned. It's not working at all now.

With no spare parts or circuit diagrams available I came up with a genius plan.

That's right- Buy another one!



They sent me a 350 amp one. Which must be inspired by Spinal Tap as the dial goes to 350 but it's still a 200 amp Tig from what I can see.

 

[JOEPRO]

As can be seen in the above photo, my foolish decision to buy another one does have some immediate diagnosis benefits.

I swapped the control panel over from the none working one and no difference so I can rule out the control panel.

In terms of taking readings with a multimeter at least I have an identical working unit to compare readings to.

What I am temped to do next is swap the lower HF control board over between welders and see does the fault lie in that board.

 

[chrismac]

There is counselling available for such conditions, please talk freely here if you wish, you wont be judged anymore than currently
You are going to town on this one!!

 

[BrokenBiker]

you actually bought another one? thats an impressive effort...

does the fake 350 work properly?

i notice in one of your other replies after you got it working you said it is lovely to use, which is the most annoying thing about this whole thing as i actually feel like that little chinese unit welded smoother than the hitbox i replaced it with, and it was more stable at really low amps even with a 2.4mm tungsten. the hitbox arc will start to wander below about 40 amps unless i go down to a smaller tungsten, but that plasmargon thing would taper off right down to 10 amps beautifully...until it died on me of course. the hitbox does have that going for it, it still works

hopefully having a working test subject will atleast lead you to the actual fault now though, and if not you have atleast got a box of spares for the working one

 

[JOEPRO]

you actually bought another one? thats an impressive effort...

does the fake 350 work properly?

i notice in one of your other replies after you got it working you said it is lovely to use, which is the most annoying thing about this whole thing as i actually feel like that little chinese unit welded smoother than the hitbox i replaced it with, and it was more stable at really low amps even with a 2.4mm tungsten. the hitbox arc will start to wander below about 40 amps unless i go down to a smaller tungsten, but that plasmargon thing would taper off right down to 10 amps beautifully...until it died on me of course. the hitbox does have that going for it, it still works

hopefully having a working test subject will atleast lead you to the actual fault now though, and if not you have atleast got a box of spares for the working one

The 350 sort of, nearly works

It won't start welding with a normal gap. Aka the HF spark works OK but it seems like you have to hold it about an inch off the workpiece for it to weld normally.

I sent a video to the ebay seller and they ended up sending me a £180 refund. No actual technical or spares support!! Ps it seems like these have dried up on ebay in terms of the cheap ones, they are all out of stock. £597 on aliexpress.

It is still usable just a little irritating. It could be poor quality earth lead too.

Anyway it's working on the trigger so as you say it's certainly useful having 2 of them now as I should be able to swap parts and narrow down the problem area on the none working 225. I'll tinker at them as and when I get time with the intention of trying to get both of them working properly.

 

[BrokenBiker]

The 350 sort of, nearly works

It won't start welding with a normal gap. Aka the HF spark works OK but it seems like you have to hold it about an inch off the workpiece for it to weld normally.

I sent a video to the ebay seller and they ended up sending me a £180 refund. No actual technical or spares support!! Ps it seems like these have dried up on ebay in terms of the cheap ones, they are all out of stock. £597 on aliexpress.

It is still usable just a little irritating. It could be poor quality earth lead too.

Anyway it's working on the trigger so as you say it's certainly useful having 2 of them now as I should be able to swap parts and narrow down the problem area on the none working 225. I'll tinker at them as and when I get time with the intention of trying to get both of them working

I noticed the 225 would do that thing with the long arc every now and then, I just assumed it was me to be honest as I was still only a few days into trying to figure out tig welding