wire feed problem

[mk2 gti]

murex 135 tradesmig ,wire feed motor runs as soon as its switched on ,it hasent been used for a few years ,at first the contactor wouldnt work wen triggers pressed ,now the contactor works but the wire feed motor runs consantly ,the longer its on the faster it gets ,id rather not buy another welder as this was a good one ,ive seen today on ebay a place doing pcb boards ,im also thinking some of the switches either didnt turn or was really tight , any ideas anyone

 

[eddie49]

Hello and welcome !

There are a couple of earlier threads that may be useful:

Thread 'Eland 160 Wire Speed Full On'

May 23, 2020

Hi All
The wire speed on my Eland 160 is stuck on full. I've replaced the IC and the power transistor (although I'm unsure whether these are related other than seeing these mentioned on other threads related to wire speed control) and this has made no difference.

I've also checked out both the wire speed potentiometer and the connections to the PCB and these are fine. POT resistance varies from about 10K ohms down to zero.

There doesn't seem to be any breaks on the circuit board or dry joints. It was working OK for about half hour after I first switched it on after not using it for a...

• Graham Francis
• Replies: 6
• forum: Welders and Welding Machines

T

Thread 'Spark but No Arc - Murex 135'

Jun 29, 2019

If anyone has got any ideas why my trusty Murex Tradesmig 135 has stopped working I would really appreciate it.
I've had this machine for years, bought it second hand and not used it in a while.
Everything seemed fine, got gas and wire feed, can hear the relay kicking in on trigger but I get a spark but no ARC.
I thought it might be the earth, so I tried another lead but the same. I opened up the cabinet to look for loose/dirty joints, went all through them making sure they were tight, the capacitors look ok to me so I have run out of ideas.
Any thoughts or suggestions gratefully...

• TR6 Rebuild
• Replies: 18
• forum: Murex & BOC

The circuit diagram in Post #15 of that thread shows that the wirefeed motor connects to Pins a7 and b9 ( for that version of the PCB ).

The fault on your welder could be an electronic fault on the PCB ( e.g. a shorted transistor ), or it may just be a loose or corroded connection or a dry soldered joint. To start, try rotating all the dials and switches forwards and backwards several times, then set all the options to Zero or Off. Please post a photo of your control PCB.

 

[mk2 gti]

would it be worth buying a pcb board ,ive no idea wot im looking at

 

[badabec]

Try the knob twiddling and switch switching first. Once @eddie49 has seen the picture the solution may be easy.
A new board may not solve any switch issues.

 

[mk2 gti]

its been standing a good few years ,the contactor wasent working an i did turn one of the nobs an it did work but now the wire feed motor runs all the time as soon as its switched on ,i wouldnt even know of anywer near to me that i could take it to to hav it fixed ,it was a good welder an id rather hav it fixed than buy a new or second hand one

 

[mk2 gti]

that nob is really stiff

 

[badabec]

With the lid off, have you tried repeated good squirts of switch cleaner whilst you rotate the knobs?

 

[mk2 gti]

i hav sprayed the switches ,the red switch that you use to feed the wire ,the one by the motor ,just tried an that isnt working now iether

 

[badabec]

Good pictures of the pcb next.
What did you spray them with?

 

[mk2 gti]

wd40 contact cleaner an some other stuff , wen i turn the switch the one in pic ,the contator wont work but if i turn it a bit it does work ,an that switch is really stiff to turn , never let me down this welder

 

[mk2 gti]

this is the pcb board

 

[mk2 gti]

wen i press this red button ,wot usually feeds the wire ,it now slows the motor down

 

[Seadog]

You need some illumination on those shots.

 

[mk2 gti]

i kno mate ,not the best pics