berlan bmig140 arcing without trigger being pulled

[croagy]

The wire at w goes to the wire feed motor.

 

[croagy]

Bump

 

[mike 109444]

Bump

Q1 Did you check the resistance across the X an Z for a short ?
Q2 Did you get and fit a new transformer ?

 

[croagy]

Yea there was resistance across x and z
Fitted a new transformer and it blew up as soon as it was switched on..

 

[mike 109444]

Is it possible that you fitted the new transformer the wrong way round ?
How much resistance did you find when you metered across x and z ?

 

[the snooper]

Is it possible that you fitted the new transformer the wrong way round ?
How much resistance did you find when you metered across x and z ?

My thoughts exactly when I read it

 

[croagy]

Don't think so.. I repaired the original one as a test. and it did the same thing..
What could cause them to blow in the first place? Before I buy another one to blow it too

 

[mike 109444]

It could be you have a "short circuit" on the secondary side of the transformer as in across X and Z. You said you got a resistance reading across there, what was the reading ? Try unplugging the 4 pin plug and note the reading then, is it different ?
Does the wire feed control connect to the 3 pin plug at bottom of pcb ?
If the W pin connects to the motor where does the second wire from/to the motor go ? (back onto the pcb 4 pin plug?)
Also note the small transistor at the bottom looks to have a blob across the bottom two pins ??

 

[the snooper]

de solder the transformer (make sure you are safe) power it up and measure for a voltage on the output side of the transformer there should be no voltage but the only way it can go bang is if you put mains into the secondary windings of the transformer

 

[linuxmadeira]

Can you help me
I have my machine Berlan bmig 140
I disassembled my machine, to paint, because it had metal rust, lost the wire connections, no spark and not even advance the wire :-(
I need a scheme, or complete photos, I really need bmig 140 to work
I already did fuse test, it gave ok and others, there are no burned parts
thank you very much

 

[linuxmadeira]

I already tested all the parts, relay, diode, torch, motor launch wire (12V), button, everything is ok,
When I turn on the welding machine, only one piece fan is working, rest is all stopped ???
PCB board receives 240v and goes to 24v
I tested with multimeter, all wires, not broken, everything is ok
There is anything is hidden, I am not seeing the source of the problem !!!

 

[linuxmadeira]

I could do a direct test, with the machine turned on, connect relay (PCB) with 12v battery with correct polarity, to see if it gives some current voltage signal,
but I do not want to do the dangerous experiment, can give very big problems!

 

[linuxmadeira]

sorry i write bad english i am portuguese But you understand I'm trying to convey my machine problem

 

[eddie49]

A search for Berlan BMIG 140 does produce a few results, with some internal pictures that may help you to confirm that you put all the wires back in the correct places. For example, this Czech site:
http://www.svarforum.cz/forum/viewtopic.php?id=11511

On the PCB, you have 24v - is that AC only, or is there a rectifier, and have you also checked the 24v DC ?
The T-shaped blue object is the relay which should be enabling power for the primary of the main welding transformer. If you can identify the relay coil connections, there should be about 100 to 200 Ohms resistance there. The relay contacts will probably have wider printed tracks and will go to external wires that feed 240v AC mains to the main transformer.
You could put your voltmeter across the relay coil and, carefully with the machine powered up, check that voltage is applied to the coil when the torch trigger is pressed.

And welcome to the Forum ! Do you run Linux ? ( I'm on Ubuntu 14.04 )

 

[linuxmadeira]

my berlan bmig 140 - PCB

 

[linuxmadeira]

I found the problem

 

[linuxmadeira]

I found the problem

 

[linuxmadeira]

correct connection

 

[linuxmadeira]

multimeter test

 

[linuxmadeira]

test lamp 24v