Diodes needed for Murex Tradesmig 245

[willsussex]

Hi all
I bought this nice old Murex at a local farm auction supposedly working , but it plainly isn't. There's no voltage at the torch. (Wire feed runs)
Transformer seems ok, so I unbolted the main diode blocks (2 diodes in each) and tested them . The top one checks out ok with 300mv on each diode in one direction only but the bottom one is open circuit.
Does anyone have a new or used spare diode block? The part number seems to be MDD 130-04 9948 only similar looking EWM diode on ebay has a different internal layout looking at the diagrams on them. Hoping someone can help, I would imagine many machines used these diodes. Thanks.

 

[Ace Paul]

you can buy individual diodes off eBay for welders. Or. Rectifier

Just search.

 

[eddie49]

Here is an earlier thread about a MIG welder that uses an EWM diode module:

A

Thread 'Dan-Mig 140 Bridge'

Apr 10, 2021

I'm new to welding and welding equipment. I came across a Dan-Mig 140 that is free for me to use/learn on. The one catch is I need to fix it first. I'm pretty sure I found the problem, one of the diodes in the rectifier is shorted out. Problem is, I can not locate a replacement, and it doesn't look anything like the other bridges I've seen on this forum. Pictures below. Any help would be greatly appreciated.

• akrover
• Replies: 9
• forum: Migatronic, Thermal Arc

I have not found the exact MDD 130-04 dual-diode module. [ The 9948 is a date code, week 48 of 1999.]

This 1600v 200A module would do the job:

Pardon our interruption...

If you replaced the open-circuit diode pair with one of these modules and kept the working one, you would be replacing only 2 of the 4 diodes in a bridge rectifier, but I doubt if that would cause a problem.