old boc/murex relays??

[pastiche]

hi to all
i hope that some one can help the company who i work for recently purchased a boc(murex) transtig 375 as i had used one before and it always performed fine, how ever shortly after purchase there was no control of the power on the pedal and only power selection on the range swithes i.e in the 100- to 200 amp range i would get 100 amps in 20 -100 amps range(or whatever the range is writing this late can't remember numbers) i would only get 20 amps and no further control on the main power dial os mentioned the pedal.
we beleive this to be caused by failure of 1 or more relays in the machine? if any one knows better please help but if as we suspect it is the relays can anyone tell me where i might source the correct replacements as finding them is proving very difficult.
this request is quite urgent as we are only small company and not having the abilty to ali weld(we have a smaller dc machine) is costing .
if they are not available would it be possible to use anothe relay and maybe wire it direct into terminals rather than plug in.
thanks in advance

 

[Jake SS]

Doubt that it would be a relay problem, the relays are usually only for control circuits,
Does it work OK on local control with stick and or tig?
Check foot pedal pot and wires and where it plugs into machine and at the back of the plug internal
From memory there is a snubber PCB near the rectifier, maybe thats causing a problem.
Pull all plugs and check pins and sockets and plug back in
Look at every terminal and connection for heat, etc
Has been a long, long time since I have seen one of these machines. IF it is actually the machine that I am thinking it is.!!
I may have something at work on it, will check it out
Do you have a part number and serial number of machine?

Cheers
Jake

 

[pastiche]

have checked foot pedal twice and it appears fine altough the winding is loose in places the continuity appears to be good have not checked mma will do that today and will find out any numbers on it today and post later thanks for the reply

 

[piman]

Hello Pastiche,

as far as relays go, RS (http://rswww.com) components have a huge range so you should be able to find a suitable replacement. Don't worry about getting the exact make as you have installed, just get the right rating (amps) coil voltage which could be AC or DC and the correct contact arrangement.

Alec

 

[pastiche]

can not find any more id numbers and have checked with mma and there is no diff only get lower power from range selector and no control on main dial you seem to be right the relay does seem to be working so prob would appear to be elsewhere

 

[Jake SS]

Sorry mate cant find any info on your machine.

Can you post some close up photos of switches, dials, etc and photos of internals also, may help to jog my memory!
But if you are in a hurry take it to someone local

Cheers
Jake

 

[pastiche]

will take some phots jake taking it to some one local not much of a option i am in the algarve potugal not much back for welder fabricators in this part of the world just finding consumables can be hard work.
cheers for your time so far
later paul