MLS2300 possible PCB fault

[Shox Dr]

Opened my set up today for its annual clean/check, and found this



On the other side is a bank of doodads

And they get hot.


Set shows no faults (barr facia knob). Although it does some times not want to start inC 30amp (ish) 1.2m tungsten 5lpm on bright 316 sheet. Not tried anyother setting this week.

Are they any Kemppi techinal support/dealers reading please feel free to pm me.

Or comment here.

Anyone

 

[eSCHEn]

Possibly bleed resistors?

They're 47kΩ SMD resistors. That bit I'm sure about.

 

[Shox Dr]

Might be

They certainly get bleeding hot

 

[Richard.]

Have a part no for that board?
I think I've a parts list for it somewhere if you need it.

 

[Shox Dr]

Not yet, I'm waiting on a mate having a look, he hasnt got back to me yet

 

[Richard.]

If it's a genuine replacement board needed id imagine it's a pricey fix.
On the other hand it's a top class machine and certainly would be worth the spend.

 

[HughF]

If you want them changed, I do smd rework for my day job (amongst other things)...

 

[the snooper]

If you want them changed, I do smd rework for my day job (amongst other things)...

could do to find out why they are getting so much current

 

[HughF]

Figure that out, no... Change them once you know they are problematic, that I can do... I'm not a board level repair engineer, more of an smd rework genius, the engineers tell me what to change, I do it...

 

[daleyd]

more of an smd rework genius

Nobody likes a show off Hugh ...

 

[Shox Dr]

I'll be calling Kemppi first thing Monday, to ask about any known faults. Hopefully they'll help

 

[the snooper]

I'll be calling Kemppi first thing Monday, to ask about any known faults. Hopefully they'll help

give them the numbers of the resistors that are heating up, I have 2 amplifiers that are known to blow 2 diodes on the PSU from a certain production run, and mine was one of them, repaired FOC but a pain when you are using them and all of a sudden the subs are off

 

[Shox Dr]

I doubt this will be repaired foc, its 9yrs old. Plus they charged me 65quid to replace the main control dial, said it was a known fault, the set was less than 2yrs old. They then lost me panel and had to replace with the high end version, and thats on the blink ad well.

Mate said the part's around 6quid. So he might as well do that at the same time.

He can be a bit funny at times though, so thanks for the offer

 

[Robotstar5]

I'll be calling Kemppi first thing Monday, to ask about any known faults. Hopefully they'll help

I've had a few problems with them before, bought a new welder to integrate with a robot and couldn't get it to work properly so phoned Kemppi and was told "Oh that's a known software issue, we'll send an engineer out to sort it", why didn't they sort it before selling us the welder?

 

[500e]

Looks like heat soak after a period of use\time if your mate is good with SMD get him to put 1\1.5 mm support blocks between solder pad & resistors, the air flow should stop the board going crisp.
Have done this on expensive commercial boards that have a habit of turning to charcoal in sections

 

[Richard.]

thats on the blink ad well.

What's wrong with the panel shox. My acx panel was as good as gold. I've heard they are a fortune to get new.

 

[Appyasme1]

Kemppi will only sell you a new PCB,no Service Exchange.Yes Richard you are correct,you are looking at at least £600.00 for a new PCB plus carriage plus labour.Not good.There have been several updates to your machine.I can help you with this info if you wish.

 

[Appyasme1]

Kemppi will only sell you a new PCB,no Service Exchange.Yes Richard you are correct,you are looking at at least £600.00 for a new PCB plus carriage plus labour.Not good.There have been several updates to your machine.I can help you with this info if you wish.

Kemppi will only sell you a new PCB,no Service Exchange.Yes Richard you are correct,you are looking at at least £600.00 for a new PCB plus carriage plus labour.Not good.There have been several updates to the machine.I can help you with this info if you wish.

 

[xmetal]

Looks like heat soak after a period of use\time if your mate is good with SMD get him to put 1\1.5 mm support blocks between solder pad & resistors, the air flow should stop the board going crisp.
Have done this on expensive commercial boards that have a habit of turning to charcoal in sections

That would be the best option and my preferred solution. Even discrete resistors standing away from the PCB (if they didn't change the board characteristics) would be better than doing nothing.

 

[wilbur]

They're clearly intended to dissipate a lot of power (i.e. heat), because no-one uses SMD resistors in big packages like that, or parallels them up like that, unless they want to dissipate lots of power. I suspect that they might have considered the rating of the individual resistors without thinking about the effect of six of them in one block together - the resistors are probably fine but the PCB is struggling with the temperature. You should expect them to be (very) hot, that's probably not a fault.

I would probably replace them with some wirewound resistors of a suitable rating - if you measure them accurately (digital calipers) you can (I can if you want) work out what rating resistor you need. You only need 1 or 2 parts to replace them all, because they're in parallel pairs.