Hello and Help!!!! sip topmig 195

[ruuman]

Hi all,

I'm a long time reader and I swear I used to have an account here, but that was many moons ago

I'm looking for a bit of advice, my long serving Sip topmig 195 has stopped working. After much reading I've come to the conclusion it must be the PCB but just want to ask your advice.

The welder has lead a hard life and I must be the 4th owner, I got it non-working for fixing an air compressor. After fitting a eurotorch it's been pretty good apart from the usual SIP crap wirefeed issue, was never any use on thin metal ethier.

So the problem is the power light still comes on, the fan turns, I pull the trigger and nothing. I've checked with my multimeter the power switch, torch trigger, remote relay and thermal cutout and they all seem to be fine.

PCB board, it's the two wire type

The remote relay, I hoped the black burning ment this was the issue, but after cleaning, it makes and breaks fine with good continuaty.

I'm just getting into more complex electric circuits so could someone please identify the components here.

Any ideas what else I could check? is it worth trying to repair the board, or just buy a new one, thing is I don't have much free money at the moment, so cheaper is always better

Many thanks
Ruu

 

[BChild]

So the problem is the power light still comes on, the fan turns, I pull the trigger and nothing. I've checked with my multimeter the power switch, torch trigger, remote relay and thermal cutout and they all seem to be fine.

Power to the wire feed motor?

 

[ruuman]

I'll check the voltage to the motor in the morning, but the relay isn't energised and the air solenoid doesn't open, hence why I think it's the board.

Must say BChild, just finished reading your epic cosmos thread, really good and a great pointer for mods. Very jealous your getting a nice new mig, I had the pleasure of using using a lincon electrical mig the other day. Was so odd not spending 10mins dicking around with wire speed/feed, just pull trigger and enjoy!! your going to be a happy chap I think

 

[BChild]

I'll check the voltage to the motor in the morning, but the relay isn't energised and the air solenoid doesn't open, hence why I think it's the board.

Ahh more info - I'm not good with electrics sorry

Must say BChild, just finished reading your epic cosmos thread, really good and a great pointer for mods. Very jealous your getting a nice new mig, I had the pleasure of using using a lincon electrical mig the other day. Was so odd not spending 10mins dicking around with wire speed/feed, just pull trigger and enjoy!! your going to be a happy chap I think

On the cosmo front I'll get the bloody thing working right even if it kills me!!! (it probably will)

Meantime I have some welding I need to get on with so I've sold my soul and bought what I hope will be a decent bit of kit

 

[the snooper]

1 diode, only lets current pass in one direction
2 small bridge rectifier
3 mains transformer to power relay

 

[the snooper]

i would check all of your connections as the pcb is really nothing more then a speed controller for the wire feed, unless the transformer has gone.
you would need to check that the transformer on the board is getting 240v and also has an output i have checked a known working pcb for transformer output (same welder) and whilst still on the pcb can give a miss-leading reading of zero so it would be best to take it off the board and test for continuity and an ac output

 

[pedrobedro]

The number 2 looks like the transistor which went on my 130 Autoplus and cut the wire feed. It had 3 pins.

 

[the snooper]

number 2 is definatly a rectifier if you zoom in to 400 %
you will see a + and 2 ~

~ = ac input
+ positive dc output

 

[rtbcomp]

This should be the circuit:-

 

[ruuman]

thanks all for the help so far.

rtbcomp that looks like the circuit to me.

Right progress so far. I've checked continuaty across the PCB and all related connections. 240ac is getting to the board no issue. but after the transformer the voltage is non-existent. So at the moment it's looking like the issue. I'll be taking it off the board to double check in a second like snooper suggested.

Thanks
Ruu

 

[ruuman]

right taken the transformer off the board and tested seperately, nothing at all on the output. so that appears to be the issue. Only problem is no markings what so ever on the transformer.

anyone have any idea what the spec's would be? I'm guess 12v (the relay voltage) or 24v (what eveyone else talks about on here)

No idea on the ampage required ethier. HELP!!!

also found the exact diagram for the welder on the sip site

Cheers

 

[R Kraft]

The transformer should be a 220v to 12v at about 100ma.
Just enough current and voltage to run the relay.
Robert

 

[ruuman]

woohoo, it's working again and better than before

I decided to just use any 12v supply I had, found an old monitor transformer

I thought about breaking it down to it's components, but decided against as it had a nice heatsink and was already well design so just wired it back into the old SIP circuit

works perfectly, oddly it welds much better and the lower settings are usable again, this could be down to me fixing some other minor issues I found, who knows. I think i'm going to add a motor brake relay though as it now runs on more than it did.

Thank you all very much for your help.
Ruu

 

[rtbcomp]

You may like to alter this circuit to provide dynamic braking as well pre & post flow.

Explanation here:-

http://www.mig-welding.co.uk/forum/album.php?albumid=988&pictureid=3006

 

[ruuman]

ooooh, I like it, just like a big boys welder!!

First thing I think I'll do is extend my earth lead, it's a bit silly having a 4m euro torch and a 1meter earth!!

 

[the snooper]

i would doubt very much that you could break down the new psu they dont use a transformer the voltage will be lowered electronically the fact it works with that which is a straight dc output may suggest that a diode has gone on your board which now doesnt matter as you already have dc current

 

[ruuman]

ahh cool, I choose it as I thought it would probably have the smoothest output out of all the transformers I had and there were a lot of bit's inside!!

 

[the snooper]

ah i see yours does have a small transformer it looked very thin in your picture
yes it will have a very smooth and regulated output compared to your old psu that is the rolls royce of psu`s

 

[Tomw3324]

Hi there, I know I'm resurrecting an 11 year old thread, but, my SIP top mig 150 welder has decided to stop feeding the wire. I have seen the above modification but can't really see/figure out where the monitor power supply 12v output goes to. If there are any members still active here, could you help?

Best regards,

Tom

 

[Hutcho]

Hi there, I know I'm resurrecting an 11 year old thread, but, my SIP top mig 150 welder has decided to stop feeding the wire. I have seen the above modification but can't really see/figure out where the monitor power supply 12v output goes to. If there are any members still active here, could you help?

Best regards,

Tom

Will go back to the board - the small ac transformer is prone to fail in these - 240v ac in and 12-15v ac out - , primary side (240v) will the two pins furthest apart from each other - secondary (12-15v) will the other two pins