cut40 repair

[MrFluffy]

Does anyone have any pointers as to repairing a chinese cut40? I have access to a oscilliscope and other bits and bobs but no strong idea of whats going on inside which bit or a circuit diagram. Its from a well unliked german supplier a few years ago now, but theyre long since gone let alone supplying spares.
I emailed shop river a photo of the affected part and he said its not from the same factory as theirs so can't help with a replacement pcb.

Id like to blame chinese nastyness, but I left it on a dirt floor for weeks then fired it up without letting it dry out, so I think it arc'd out downwards and fried the lower pcb. Now it just sparks inside and makes burning smells.
A pic...

 

[mike os]

best bet would be ********** (uk based)

 

[MrFluffy]

Interesting, I havent been here in years because I have only just got my lathe/mill/tig etc hooked back up to 3phase in a new workshop, and suddenly the board is autofiltering useful links. Sad.
Im going to wager that the regexp doesnt work ifyou stick some spaces in it. So at risk of getting banned (I havent needed this place in years, so whats to risk...) ill take a guess you meant cut 40 . co . uk , which turned up on a google search.
Thanks for trying to help mike.

 

[malcolm]

If I recall correctly they joined the forum pretending to be members who were delighted with their service. We politely asked them not to. Then they were reported for spamming via PM. Link censoring seemed the best option.

Good to see you drop by Mr Fluffy, sorry you are so disappointed in the forum.

 

[mike 109444]

Mr fluffy The area you are pointing to looks to be the basic power supply part of m/c (the lower pcb) I would lable the plugs that go from the lower board to the upper. Then unplug them to protect the upper pcb. then do basic power board checks. If where your arrow points is the burned cooking parts then probley one or more of the bridge diods may hav shorted. also the blue discs which are (can't think what there called, long day...) are usually to dump spikes on the power input and if shorted will cause problems you discribe. All of the above assumes that you are confident with mains and using a dvm if not.. stay clear and get a sparkey to check the power supply pcb. Any more pics of pcbs ?

 

[R Kraft]

If they are surge suppressors,they would be called MOVs or varistors.
In the tiny picture that circuit looks like a bridge power supply or a voltage multiplier.
Robert

 

[MrFluffy]

Robert, WAS a bridge recitfier area is probably the best way for me to put it.
Back (lower closest to the case bottom) side of the pcb, you can see the burning pattern which suggests the arc originates from the spark gap area.
http://gallery.pipandphil.com/v/Vehicles/workshop/plasma2.jpeg.html

On the upside, is the remains of the bridge rectifier area, along with some now very deceased unidentifiable components.
http://gallery.pipandphil.com/v/Vehicles/workshop/plasma1.jpeg.html

The people mentioned above have offered to supply a replacement pcb for 26 pounds, which given the time and effort I would expend with digikey and research represents good value for money to me, so the pcb is going on holiday in a jiffy bag to the uk.

 

[R Kraft]

Horribly carbonized,not likely repairable by anyone,glad you found a replacement.
Robert

 

[MrFluffy]

It lives!

Just to update this, like I do, I got in touch with the above not to be mentioned company and arranged to send them the melted pcb from my unit, as shipping from France for the entire unit would have put the price up considerably.
Although I said in advance I doubted there was much to be done with the original, they offered to take a look anyway and see if they could replace damaged components.

Mike @cut40 looked at it and pronounced it dead (as rightly it was) and sold me a new complete pcb from stock for 26 quid. Ive just received it and its working perfectly, so I'm a happy chap who wont be leaving his unit for months on soil floors again!
Any delay between the above and now were down to myself, the turnaround from cut40 has been really quick, with good communication via email.

Sounds like a advert Malcom I know, but I think you know I call a spade a spade, and end result is a working plasma which is really where I needed to get to.
Going to butcher my van with it tomorrow now, after watching a round of the 2cv supercross which is local

Thanks to everyone who helped.

ps there'll be a round for the renault 4's too, but theyre not as exciting to watch as they seem more careful than the hardcore nutters in the citroens. Has to be experienced to be understood, 4 autocross racing prepped 2cv's entering a muddy corner wide enough for two abreast at best with huge banked sides, mostly sideways