Unimig Multi 250K Pulse Mig KTRPM250K Questions & Answers

Hi David, please contact our service department, they will be able to assist you with this: external link 

So I don’t have any wire feed at all circuit board has around 18v and when jumped wire feeding starts it’s not getting any signal. Switch is definitely working as gas solenoid is clicking. Any help would be appreciated.

I would presume that the problem is more in the board. I have got rid of some issues by pulling apart( very carefully) some of the multi pin electric plugs, then cleaning them as much as possible with a quality electric spray for cleaning joints and boards, put them back together and apart a couple of times. Put it all back together and try the trigger. If that doesn't work, I get mine to go by lifting it up 100 mm then dropping it on concrete. That has been working for a few years now. A good welding electrician may be able to diagnose it better but some only want to swap boards until a.machine works.$$$$. Hope this helps. Russ.

Yeah ok I’m pretty sure I can replace boards if that’s the case I’ve hardly used this welder.

Hi whitweld, I have some similar problems with my 250 k. I have to make sure the filler wire isn't close to the work when I pull the trigger or it can go nuts, especially if I have the arc length on negative for more wire feed. It also blasts up to peak amps when it gets warmed up and I do a long weld (over 75mm). You are probably right about the programming, but previous experience of this type of thing usually means swapping out parts of the electric boards until it works and can be expensive. Give the Sydney agents a call and suss it out. Keep me posted, my email is [email removed]

Hi Russell , I did a few different setting and sometime it work fine than for no reason start to play up again. I had it repair a few years ago by a Unimig contractor in Brisbane and after two go at it it run even better than new. I did fit the push pull gun which made the machine very useful.But now it is playing up and as I said the program is out of wack. There is a plug inside to up grade the software so I think it should be possible to reinstall it as well. Will need to contact Sydney and find out but don't want to have to send the machine and the Brisbane technician is not working with Unimig any more .I though may be some one would have try to do the software up date ( my software is the latest so Brisbane technician must have up dated it when he service it, as my welder is one of the first one it didn't have the board for the push pull gun preinstall? Will call Sydney tomorrow and ask .Thanks

If it burns through, you've got too many amps. You may be on the wrong arc length which will act like slow wire speed. It's on the up/down button to the right of the main dial . Press it until (arc length) appears above the numbers. Alter the main dial until you get a minus number which means shorter arc which means it pushes more wire to shorten the arc. Play with that and see what happens. Rule no.1 with Ali is that even new stuff needs to be wire buffed or hit with a grinder before trying to weld as the oxide on it doesn't melt as easy as fresh oxide and practice with 3 mm thick or more to start with.

Thanks I'll try that I am welding 3mm tubing I did manage to get a reasonable bead with the material thickness dialled down so perhaps I'll bring that back up and adjust the arc length to suit, thanks for the heads up on buffing it back I'd never heard that before

Hi Maso, my machine also comes up with this occasionally. You can ring Welding Guns Australia, which are Unimig agents in Sydney and the tech guy there may have the answer or they may want to check out the machine. The method I use which seems to work, is to turn off the machine , leave it until the lights go out and then lift it about 75mm off the floor and drop it to give it a good shake up. When I turn it back on ,it has worked every time. I think it all stems from dodgy connections in the multi pin plugs in the machine. At one stage I pulled them all apart and cleaned them with contact cleaner and all went well for a while. Of course the risk is that the thing will break, but my anger levels got to me the day it locked up on that code and it made me feel better to thump it, and I've never looked back. Mine has probably had about thirty shake ups and no bad side effects , so its your call. Good luck, Russ.

Hi Jim! Haven't had that error message on mine. Welding Guns Australia in Sydney can explain the error message. I would guess it might mean 'test alarm' which might mean it's tested it's circuits and isn't happy with what it has found. Check earth and clamp or find a competent welder repair guy. If you want to go further yourself pull off the side and top cover, pull apart all the bayonet connectors you can see 'carefully' and put them back together and try again. Good luck!

Thanks Russell....I were thinking along the same lines and had already removed the covers and main ribbon cables ,gave all the boards a blow with low pressure air (was a bit of grinding dust and a few spider webs around ).Re assembled and it fired up no problems.