Help Identifying Electrical Components

[tardis454]

My friend got a Thermal Dynamics Pak Master 50XL Plasma cutter for free. The reason it was free is because someone hooked it up wrong and fried some components on the Fet PC board. He identified most of the parts, but there are 3 cylinderical parts above the Mosfets with no markings. I told him they look like high voltage rectifier diodes. The service manual doesn't have a schematics parts list making it a crap shoot on what to buy seeing that we don't know what the part is and/or what size/values to buy. The components in question are circled in red. See photos...

[SuperBuickGuy]

yeah but those aren't the problem, they're just what burned. I had a 50XL - and I know your pain because you cannot buy another board for it. It died exactly the same way, but the welding repair place got asked the very same question you're asking, they replaced the capacitor and a couple resistors then it burned again. The problem is there is a flaw in the control chip .... and that's proprietary, so there isn't someone who makes a replacement. I used my 50XL as trade-in on a new plasma (got $200).... wonder if someone dumpster dived it and it's now on your friend's counter....

[SuperBuickGuy]

remember, I've made all the mistakes - it really is the only thing I'm good at...

[tardis454]

Thanks for the input Mr. Christensen. I sent my friend this link to let him know what he's getting into.
He also mentioned a trade in credit from Thermal Dynamics, and that may be the route he goes with this.

[Beagle]

I know less than nothing about it, but would a datasheet for the MOSFET give you a sample circuit that might give a clue?

[SuperBuickGuy]

Thanks for the input Mr. Christensen. I sent my friend this link to let him know what he's getting into.
He also mentioned a trade in credit from Thermal Dynamics, and that may be the route he goes with this.

I'm not in love with my new thermodynamic - but not so hating of it to sell it and get a Miller. Buy a Miller. I have a dastardly plan and am getting the parts made right now to build a plasma table. I'm buying enough parts to build 4. My plan is get the first working with the thermodynamics then make it someone else's problem by selling it then getting a miller... oh and then using my laser welder and converting it to a laser cutter.

More specifically, the problems I have with the TD is:
1) they sell proprietary parts, Airgas has their 'own' torch so you're stuck buying consumables from them. So consider - TD didn't keep building boards for 10 years after stopping production of the 50XL, how long do you think it will be before I'm buying another torch because Airgas says "it's not selling consumables fast enough?" ... I don't know which I dislike more, TD for doing this, or Airgas for not mentioning it when they sold it to me.
2) it is not as powerful as they claim it is - also it flat eats consumables. I think it'll be better with the plasma table that has Z control, but in the end, even with the drag tips, it might get 48" of 3/16 cut before the tip is gone....

and there is an implied 3) they put the cuss in customer service.


Buy a Miller or even Hypertherm....

[Barry Donovan]

green means it could be a one off "experimental"

before rectify and burned, I would guess they attempted resistance,being one circuit bigger than the other for rectify.

either way the engineer lost.

I far from expert, I learn by burning things.