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| Ever been so mad at a project you wanted to just smash it into the concrete? |
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| coppercone2:
It looks like the heavy coils come out OK, the entire magnetic front end of the welder is pretty serviceable, you need to bend some bus bars to get stuff out, or is it heavy square wire, whatever... maybe miller could cut some slots that are reinforced with plates so that stuff comes out with less bending though. Like unscrew a plate over a slot so that the heavy wires can lift out instead of having to be pulled out, you could probobly do it with 1 bent tab and a single screw or even some spring in place crap Lots of crap still in there, tried to get it off with spray alcohol and a air hose before disassembling but I see that the greasy dust aint gonna come out of there easily. And the plate choke could use some more laquer or a better paint process, it should not go off this quick with surface rust, but I guess it probobly gets hot down there at high currents so its probobly hard to prevent that And they gotta do a better job with that honey comb air vent thing they got going on, its clever for air flow but cleaning that is a total pain in the ass, they should have screwed in a structural vent there (that is both structural support but also a vent) that you can remove and wash. I do like that the large diameter air coil is on a bent bracket that screws in with only 2 big bolts, thats a really nice feature for cleaning. I would give the magnetic section a 4/10* for build quality, and the air intake system a 3/10 for clean ability, FUCK that caked up mill scale shit in the honey comb!! If you could take that vent out like a slot it would be REAL nice. Put a stainless pipe latterally to stabilize it and stop making god damn monolithic vents Bet this thing would have not exploded if it was easier to clean.... *I would have given it 8/10 but I renembered that the transformer is built mad bootleg. They stuffed a teflon tube into a winding and then jammed a wire thats loosely wrapped around a ferrite rod in there. Its like a gimmick capacitor style. That needs to be made a real part because its ridiculous! That component looks like it came off Hindu-hacktube! I dunno if that was an attempt at a adjustable core or something but holy crap if your just jamming wire into a tube thats super bootleg. Dude musta been a pump designer that transferred to electronics because its like hydraulic wadding or something lmfao, I don't want high power blunt wraps. Irma say that's 20/10 for prototyping power electronics but for premium retails GET REAL. I felt like I found a knife stuck in the patient :o |
| coppercone2:
lots of cleaning, every component resulted in a dirty ultrasonic bath (I put fresh liquid after each subassembly). Now I will bake them out, clean up some of the bigger connectors and conformal coat the reworked board, varnish the transformer exterior after a bit of rust removal, change the rusty bolts on the spark gap arc start, and hopefully it will turn back on again looking fresh inside ;D. Even the inside of the relay was filthy, I carefully dipped it in the cleaner as not to get the coil wet though, I don't trust those relay coils for getting wet. still cleaner then that one harrison power supply I got on ebay though, that think was RANK² |
| helius:
--- Quote from: coppercone2 on May 26, 2023, 08:48:15 pm ---what conformal coating do you recommend to recoat miller boards? I ordered mg chemicals silicone coating, so I can redo the coat on the mainboard. --- End quote --- I've had good results with it, but the fumes are noxious (ethylbenzene) and it takes a fairly long time to harden, like 6 hrs. It does flow and level very easily. |
| TERRA Operative:
We used to use MG Chemicals stuff in the workshop, but I'm not sure now what conformal coating we used exactly. It was a high voltage rated one in a spray can we bought from RS Components. If you buy the highest voltage rated one you can find in the RS catalogue, it was probably that. |
| coppercone2:
I was a little worried about temperature and flex because the PCB is kind of one of those bugs bunny things that wobbles like a diving board and there is some power resistors that over heat, so I got silicone But, if you compare the dielectric strength, its 1000V/mil, vs 3000V/mil for the dielectric/insulting one Do you need to get the higher value one? When I see a 300% difference I got a little worried i.e. silicone conformal coat vs super corona dope (1kV / mil vs 4kV/mil) This welder coating discussion has a new thread now, so I don't hijack the stories thread https://www.eevblog.com/forum/repair/conformal-coating-for-tig-welder-pcb-(milller)/new/#new |
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