lack of information to repair/fix ct312 multi welders

[philp aldworth]

I have a ct312 multi function welder which has failed but did function well for some time. I have spent some time examining the device with a multi-meter and oscilloscope but without a circuit diagram or block diagram it is impossible to trouble shoot. I consider it is well constructed, but scouring the internet, nobody has any help to give. I notice that there are a considerable number of indicator diodes which I presume help diagnoses. I assume the manufacturing company Pela Tools/Richmond/or Shenzhem wishes to limit the information available for financial reasons but I feel that it would enhance their product if they encouraged both DIY and professionals to repair what is a good product, with backup available, and would undebatably improve both sales and reputation. My feelings are that there are a good number of ct312 owners that feel frustrated that a product which is ideal for the DIY engineer is let down by this situation. Could there be any body in the forum foolish enough to collate the inputs from ct312 owners and forword to both manufacture/suppliers and possible develope a positive dialog. On a lighter note it took me twice as long to type this as it took me to angle grind my wellding down to level aceptable by a myopic MOT inpector.

regards Phil

 

[hotponyshoes]

I thought there was supposed to be some sort of directive now that forces manafactures to supply repair information and parts to end users?

Might be worth seeing if it actually exists then quoting it to them if they are not forthcoming.

That's presuming you have tried the nice "could you send me a diagram please" email to them first?

 

[Ace Paul]

Yanks. Right to repair.

See if sold in USA. Get USA member to ask for information.


Is it ‘cheap enough’. Buy another, new or used. Use to fix this one?

Is it totally dead? Can you fax some photos over?

 

[eddie49]

Hello and welcome to the Forum.

The Pela Tools CT312 is perhaps this 3-in-1 Plasm Cutter, TIG, and Arc welder:

Buy Plasma/TIG/MMA CT312 at Pela Tools

Buy Plasma/TIG/MMA CT312 at Pela Tools - Carefully selected High Quality tools since 2003 - For both professionals and DIYs!

pelatools.com

If so, did you do your MOT welding with TIG or Arc?

 

[Ace Paul]

Google each and every chip on the board. Enter number on it with that with data sheet

 

[philp aldworth]

Yanks. Right to repair.

See if sold in USA. Get USA member to ask for information.


Is it ‘cheap enough’. Buy another, new or used. Use to fix this one?

Is it totally dead? Can you fax some photos over?

Like the right to repair idea but there is no visual damage , no capacitors blown etc or overheating present and as I have sold my MG midget so no requirement at present to buy a new welder as I also have a stand alone MIG. It just seems a shame to dump what could be a good bit of kit and I like to repair anything I can. Thanks for response

Hello and welcome to the Forum.

The Pela Tools CT312 is perhaps this 3-in-1 Plasm Cutter, TIG, and Arc welder:

Buy Plasma/TIG/MMA CT312 at Pela Tools

Buy Plasma/TIG/MMA CT312 at Pela Tools - Carefully selected High Quality tools since 2003 - For both professionals and DIYs!

pelatools.com

If so, did you do your MOT welding with TIG or Arc?

.

 

[philp aldworth]

Bare with me as I finding it hard to know how to use the forum properly so if I have failed to respond please, take no offense, as I am not sure if I am to respond to each comment or just a global one here.

 

[philp aldworth]

Hello and welcome to the Forum.

The Pela Tools CT312 is perhaps this 3-in-1 Plasm Cutter, TIG, and Arc welder:

Buy Plasma/TIG/MMA CT312 at Pela Tools

Buy Plasma/TIG/MMA CT312 at Pela Tools - Carefully selected High Quality tools since 2003 - For both professionals and DIYs!

pelatools.com

If so, did you do your MOT welding with TIG or Arc?

Thanks for the welcome, I mainly used it in PLASMA mode to cut half the floor out on a MG midget but though I used the TIG a bit I used my stand alone MIG for most of the work.

 

[philp aldworth]

I thought there was supposed to be some sort of directive now that forces manafactures to supply repair information and parts to end users?

Might be worth seeing if it actually exists then quoting it to them if they are not forthcoming.

That's presuming you have tried the nice "could you send me a diagram please" email to them first?

I totally agree that the nice approach is always the way to go to get results but I have doubts as to the success of just one old moaner, such as myself will have. I may well have to rethink this negativity. Thanks for the input.

 

[eddie49]

Although this thread is 15 years old, it may provide some useful background to the topic of plasma cutter repair:

J

Thread 'Plasma Cutter Repairs'

Nov 12, 2010

Below are the details of a top quality repairer for Plasma Cutters...especially the Cut40 Series. I was one of those cheapskates who bought a Giant Cut40 off ebay on the hope it was working...guess what...it wasn't. Now the thought of having a useless piece of rubbish sat in my garage with no one else to blame but myself really really got my goat..Endless Google searches etc and a previous thread from this forum got me the details of the following..

www.cut40.com

All i have is praise for this company. The owner Mike Howard is the most approachable bloke you could ever wish to talk...

• Jim142
• Replies: 32
• forum: Plasma Cutters

 

[philp aldworth]

Although this thread is 15 years old, it may provide some useful background to the topic of plasma cutter repair:

J

Thread 'Plasma Cutter Repairs'

Nov 12, 2010

Below are the details of a top quality repairer for Plasma Cutters...especially the Cut40 Series. I was one of those cheapskates who bought a Giant Cut40 off ebay on the hope it was working...guess what...it wasn't. Now the thought of having a useless piece of rubbish sat in my garage with no one else to blame but myself really really got my goat..Endless Google searches etc and a previous thread from this forum got me the details of the following..

www.cut40.com

All i have is praise for this company. The owner Mike Howard is the most approachable bloke you could ever wish to talk...

• Jim142
• Replies: 32
• forum: Plasma Cutters

I can identify with the the thoughts generated by the presents of a non functional bit of kit every time I open my garage door. It is taking up bench space and stating yet one more failure to add to my collection of buying cheap and expecting reliability. Still cannot resist the chance of a good cheap buy. Thanks for the input.

 

[eddie49]

Both inverter welders and plasma cutters have similar power circuits, so this troubleshooting process should apply:

Start by disconnecting the machine from the mains and waiting an hour or two for the capacitors ( with up to 325v DC ) to safely discharge. Then remove the covers and check for:
- loose push-on spade tags at the back of the mains power switch and on the bridge rectifier ( rectangular alloy block mounted on a heatsink, with 4 tags, - there may be two rectifiers in parallel )
- loose bolted connections on heavy internal cables and copper or aluminium busbars, at heatsinks, and on thick tracks on the PCBs, and at the back of the front panel sockets.
- loose or poorly-seated plugs on the multi-wire harnesses between the PCBs
- any sign of blackened, burnt, or split components, especially the multiple paralleled power semiconductors ( MOSFETs, IGBTs, and diodes ) that will be attached to the large finned heatsinks.

If you are confident working on live equipment, measure the DC output from the bridge rectifier(s). It should be about 325v DC, after smoothing by the large electrolytic capacitors. It is this DC bus that runs the machine.
There is usually a soft-start circuit, using a resistor or thermistor bypassed by a timed relay, to lessen the initial power-on current surge as the capacitors charge. Check if you can hear this relay click just after switching on the machine.

This thread describes the successful repair of an inverter DC TIG welder:

Thread 'Parweld XTT182DV no power'

Oct 27, 2021

I have an XTT182DV inverter set, which is currently not showing any signs of life.

A preliminary investigation is showing that I am getting AC voltage to the first pair of rectifiers and when the DC side of the rectifiers is disconnected from the main PCB there is 240V DC. When the DC side of the rectifiers is reconnected, the voltage is pulled down, possibly indicating a short circuit.

Since the DC voltage is getting pulled down, there is no voltage on the control side, therefore no power indication light or anything else. Nothing is tripping as the short circuit load is being...

• The_Motorcyclist
• Replies: 20
• forum: GYS, Parweld, Jasic

Tec-Arc in York offer inverter welder repairs.
You could also try contacting R-Tech in Tewkesbury. They service and repair their own machines, but also offer repairs for other major brands

 

[gaz1]

there is a cut40 schemetic that they could follow as it might help

Post in thread 'cut 40 repair info'

Jul 10, 2017

@AdrianH has also done one with a cut 50 machine

http://www.mig-welding.co.uk/forum/...d-idea-for-cheap-thc-control-for-cut40.68564/

• gaz1

 

[philp aldworth]

Thanks again for inputs. So far I have pulled off all connectors and replaced them one by one. This failed to fix problem so resorted to the old method of lifting and repeatedly dropping on bench but no fix. Will try listening for relay next and I am assuming that it not the large relays which do switch when changing the mode of operation, plasma/tig/rod.
regards Phil