BOC Mig Master 130 Turbo Mig welder fault

[john fletcher 1Participant @johnfletcher1]

I have a BOC Mig Master 130 Turbo Mig welder. The wire speed control has stopped working altogether. I have removed the small board which controls the wire feed motor and notice 3 very small components looking burnt, Diodes ?  Has anyone had a similar experience and how did they solved the problem, in particular the component identification on the Pcb. ?  John

[Stuart Smith 5Participant @stuartsmith5]

John

Can you post a photo of the board and components?

A quick google found this circuit diagram which may be similar to yours:

https://www.mig-welding.co.uk/forum/threads/boc-autolynx-130-manuals.117352/

Stuart

[noel shelleyParticipant @noelshelley55608]

The original BOC Autolynx was made in the early 70s, rated at about 160A. This was probably the best small MIG ever made. 50 years ago it was VERY expensive at £750. You get what you pay for and mine is still working. Tell me more about the unit – does it have finitely variable power settings or steps ? The 70s version came with all the circuit diagrams, test procedure and a full list of components. Sadly BOC went down hill from there to some rather poor units and refused to give even main agents circuit diagrams Etc. I got caught – I bought a BOC plasma cutter – it didn’t last long. I have the diagrams Etc but I don’t think they will be any help – is the wire feed motor a wiper motor or is it much smaller? Noel.

Looking at the diagram above it is nothing like mine. Pictures of the board and blown components might give us a clue. Seeing a meter on the unit means it is probably a modern item.

[john fletcher 1Participant @johnfletcher1]

Hello Stuart and Noel, my welder is basic and old, nothing like as shown on your circuit diagram Stuart. I’ll get the granddaughter to post a picture for me when she is around. The machine is very simple, half wave rectifier and choke, the the gun energies a small relay which applies a variable 24 volt DC to the the wire feed motor. Regarding the power settings, there two rocker type panel switches, which give 8 power levels. Simple, but has worked well for many years. Its the 50 x 50 crowded wire motor feed board which is burnt in one area, relay OK. I will concoct a Vero board job if nothing turns up. It would helpful if a circuit diagram turns as I have most of the required bits. Thank you both for coming back to me.  John

[Dave HalfordParticipant @davehalford22513]

If I’m not mistaken it’s a BOC / Snap-on / uncle tom cobbly badge engineered Turbo 130A made by Cebora. I had one, nice little welder gas valve in the torch operated by the trigger.

I’m assuming the contactor still clunks nice and loud, before you mess with anything else check the contactor is feeding the motor board and if not check the torch contacts.

Contactors are known to play up also the wire feed motor plastics are brittle.

A Google search turns up quite a lot.

[noel shelleyParticipant @noelshelley55608]

Dave has it ! I have something very similar, the wire feed was what let these units down. The feed roller pressure is often poor, the plastic bits tend to flex and the feed motor speed not steady. The last issue can be cured by making a separate power supply rather than the internal one which can fluctuate. The main power transformers/rectifiers are OK (for what they are ) and for the sake of copying one of the better made machines wire feed it would make it a very nice machine. One trick is to have geared top and bottom rollers so that the wire does not slip, my big machine  has a separate feed unit with this idea. Being able to control post gas flow is good and pre gas is even better, but now things are getting complicated ! Ah well.   Noel.

[john fletcher 1Participant @johnfletcher1]

When the welder failed it didn’t do any thing at all it stopped. I have looked around, and others say it is the same or very similar to a Cebora. All I would like is a clear picture of the PCB, unfortunately on mine the identifications are burnt. So, if anyone has component details of a Cerbora please let me have a copy.  I’ll keep looking, shame to scrap it John

[Clive FosterParticipant @clivefoster55965]

“Universal” replacement wire feed controllers can be got for around £80-90 (ish). Expensive compared to a repair but if you can’t find a circuit or repair fails may be worth investigating.

Given that the wire feed unit on these machines was never the best it’s possibly worth considering upgrading the wire feed system as well as new control board. Not cheap but still usefully less than half price of a new welder with a decent duty feeder.

Crappy wire feed drives my temper up past the red “Danger UXB line” faster than an auto dark helmet reacts to the arc striking!

Clive

[Dave HalfordParticipant @davehalford22513]

Pocket Turbo 130 wire feed. | MIG Welding Forum

 

[john fletcher 1Participant @johnfletcher1]

Many thanks to you all. The picture which came via you Dave above is just the board I need, but at that price of £70 plus I will wait a while. If I knew the burnt component values its not a long job to make one on Vero board. I’m fortunate as we have a semi industrial ( car garage type) Mig at MATES of which I’m a member, so I’m not stuck. But a Mig in the workshop available anytime  is the way to go. Many thanks to all respondents.   John

[Robert Atkinson 2Participant @robertatkinson2]

If the control relay is still working could you use a generic 24V PWM motor speed controller?
Completely random example from ebay

https://www.ebay.co.uk/itm/406752328157?

Robert

[peak4Participant @peak4]

I do have a Cebora version in the workshop, but will be unable to look at it until well after the weekend.
I’m a but loathe to try and strip it, as the internals might all be a bit brittle and it’s working at the moment.
Have you seen this ebay advertiser, who lists repairs to several different PCBs

https://www.ebay.co.uk/str/yorweldsupplies

Are you anywhere near Bristol?
https://www.ebay.co.uk/itm/298123396794

Also; I’ve not seen this all the way through, the camera shake was making me seasick

Bill

[john fletcher 1Participant @johnfletcher1]

Back yet again, to Robert. Yes that’s an idea which I have thought about, at ebay prices, its hardly worth warming up the soldering iron, however, I do enjoy a bit of DIY construction. I have also had a look at Yorkweld, the repaired PCB is much than I original paid for the pre owned welder, so I will give them a miss.

To you Peak4. I’m in Scarborough and PLEASE don’t start dismantling your WORKING MIG, much as I would like PCB details. I did a conversion on my BOC 130 which enabled me to use GAS or Wire only, that was 5/10 years ago. I did another MIG conversion several years ago and details were published in Model Engineering Workshop magazine, maybe 20 years ago.

[Dave HalfordParticipant @davehalford22513]

I asked the guy on the Mig forum

 

[john fletcher 1Participant @johnfletcher1]

Thank you Dave, I have joined welding Forum and was unsuccessful searching for my PCB details, you got there, good. Its those two diodes top right and the resistor between, which are burnt. Diodes no problem but can’t see clearly the band colours on the centre resistor. Anyway a move in the right direction.    John

[David JuppParticipant @davidjupp51506]

Looks like Brown, Black, Black, Gold to my eyes – 10 Ohm 5%.

Physical size should give some idea of the power rating.

[john fletcher 1Participant @johnfletcher1]

Thank you David, mine is badly burnt and is so very thin, never seen one like it. I’ll give it a try over the week end, and report back.  John

[Robert Atkinson 2Participant @robertatkinson2]

Hi John,

Not trying to teach you to suck eggs, but resistors don’t normally burn out on their own. Something else has probably failed. The electrolytic capacitors are prime suspects.

Robert.

[Dave HalfordParticipant @davehalford22513]

The resistor by the biggest capacitor looks to have the same value too.

[john fletcher 1Participant @johnfletcher1]

Blimey, never thought I would receive such useful help, yes Dave, I had noticed that resistor being of similar value. Granddaughter visited and she soon got me sorted on the Welding forum, and I now have a very good colourful picture of the board. Amazing how these young people can see the obvious and I couldn’t, such is life. Eventually I will rebuild the board, test the important components Capacitors, Transistor, and Thyristor and go from there. I have a small stock of bits. But grass is starting to grow, then it will be hedges, so playing might have to wait until the autumn.  John

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