Jasic 200P AC/DC Repair

[Justin K]

Zero between the yellow and black, remains at zero when trigger is pushed

 

[Jan-DIY]

Please take some pictures from mating pcb.

 

[Jan-DIY]

You can also disconnect the yellow cable and measure between yellow wire to the black.

 

[eddie49]

you can buy a new one for $1,800.00 AUD

Isn't this machine just a Jasic-badged version of the ancient WSME-200 analogue AC/DC TIG? They can be bought for £380 in UK - about 700 AUD.

There are threads on this Forum about repairs on the WSME-200, such as this one:

WSME-200 faulty

Hello everyone.. I’ve just bought a lemon (from a dodgy seller). I OC voltage tested and got ~60v across the terminals, so bought it home. now I know I have a lemon (and surprise.. the buyer refuses to take it back ‍♂️) I cannot find a schematic for it.. it appears clean and no obvious...

www.mig-welding.co.uk

 

[Jan-DIY]

For sure it is.

 

[Justin K]

Please find attached a copy of the boards the black and red wires go to. I have removed the connector in the last picture. The yellow wire goes to the rear of the AC balance dial on the front controls.

You can also disconnect the yellow cable and measure between yellow wire to the black.

 

[Jan-DIY]

Disconnect or cut the yellow wire and measure between black/yellow to check if there is a problem at the bottom board.
As i read elswhere mosfet circuit needs about 9-10V to perform.

Also please test it in MMA mode!

 

[Jan-DIY]

And be careful while touching this small pcb where Black/red cables land.
It may be connected to DC-link buffer which is very dangerous when its charged!!

 

[Justin K]

Disconnect or cut the yellow wire and measure between black/yellow to check if there is a problem at the bottom board.
As i read elswhere mosfet circuit needs about 9-10V to perform.

Also please test it in MMA mode!

Tested it and it is on about 10.4V on MMA and Tig with the trigger engaged

 

[Jan-DIY]

And 0 when release?

 

[Justin K]

Yep, drops gradually back to zero when the HF stops

 

[Jan-DIY]

So we are looking for problems on bottom board.

 

[Justin K]

So I will need to pull this bottom board out?

 

[Jan-DIY]

First take some pictures from components near 4pin connector .

 

[Justin K]

Pics attached I tried to get underside too (not great) nothing looks burnt or damaged.

 

[Jan-DIY]

This is from the link i posted yesterday.
So, next step is check diodes.
The glass ones are zener.
So make sure you measure them right.

In the beginning you can check if the relay gets energized.

Not the biggest fun to get there with your probes!

Again!
Dangerous Voltage is hanging around in this area!

 

[Justin K]

Thanks, I think that'll be a job for tomorrow morning. Thanks for your help again, greatly appreciated. I'll let you know how I get on.

 

[Jan-DIY]

No problem!
You are welcome.

 

[paulo1974]

On a standard inverter welder the first part is the rectification of the ac to dc. there should be two 24v outputs one for the fan other for the gas valve. As for the 24vdc valve unplug and give a 24vdc or less 20vdc should suffice to hear the valve click. On one image that you post i saw some burn mark near the fast diodes (converting the high frequency ac to dc)

 

[Justin K]

The solenoid unit works, I have had it working in another machine without issue. Are you able to circle the burn marks for me near the fast diodes?