Broken BoroMig 160 single phase can anyone help ?

[nicnoo]

hi all

i've been donated an old boromig 160 which looks the dogs, but i quickly discovered the reason it was given and not sold.

at first everything seems to be fine the wire feed moves freely the cooling fan cools and it makes all the right noises. trouble is when i actually come to weld something it has no power. it seems to just melt the wire onto the workpiece with no penetration (a little like a birds nest) even on the highest power setting.

i have changed the tourch and earth leads for known (tried and tested) ones which improved a little (melts much faster now). but still no luck.

any ideas ?

thanks nick

 

[madkayaker]

sounds terminal. Hope I'm wrong

 

[simon718]

Open circuit rectifier diode??

 

[sloderby]

My old SIP ended up with the same symptoms, turned out it was one of the output connections from the transformer. The (Aluminium) transformer wires were connected with steel washers & the washers had corroded where the Aluminium was in contact.
At the sort of currents used to weld, it doesn't need much in the way of extra resistance to stop the welder working. I replaced the washers & checked all the connections & it worked - well it worked as well as it ever did as a SIP!

It would be worth taking the cover off (unplugged) & checking all the mains input connections & the transformer output connections in case it's just a bit of extra resistance. Failing that then I would suggest looking at the rectifier as simon718 suggested.

 

[nicnoo]

are rectifiers available ? are they set specific or are they a standard item ?

 

[Jake SS]

Yes rectifiers are available, you may not be able to get an original, but you should be able to get one that will suit, as in physical size and current rating, if there are capacitors then you would have to check them also, be a good idea to take it to someone that knows what they are doing to do any replacements, should not cost a great deal, you will have to ascertain the problems first,

 

[nicnoo]

Excelent.

I am off to work now armed with my multimeter to give the diodes a good roasting. I have a few pics that i will put on so people can see what i'm talking about.

many thanks for everyones continued help

 

[nicnoo]

Heres a pic of an identical welder to mine. i have some close ups of the regulator i will post later

 

[nicnoo]

just a few pics of the rectifier. any ideas ?

thanks

nick

 

[R Kraft]

Wow, thats a (physically) huge rectifier.
I would suppose about any modern rectifier unit, would fit where that one was.

The small orange unit on the end looks a lot like a selenium rectifier, but they haven't used those for years.
Robert

 

[Jake SS]

From what I can see the rectifier looks OK, but you would have to check the diodes, normally the "tails" of the diodes not all but some will fuse off. May have to check your switches, main transformer, power in, contactor etc
Cheers