MAXSTAR 200DX problem

[Careless]

Let's try this again.

Maxstar 200dx bought used.

worked for 2 or 3 hours on 120v/60hz @ 1ph.

brought to another shop with plug in which we use for 180amp and 225amp mig welder. have used it multiple times with various MIG & ARC units.

wired up Maxstar 200dx for use according to operators manual and double checking wires coming from transformer. All was well.

plugged 'er in. used for 30 or 40 minutes. no error codes displayed. functioned as normal. laid some tig beads on 316 SS. It then started to smoke up, so we shut it off. opened the case up to find that the front-most 450v 1500uf capacitor had leaked electrolyte from underneath. it must have leaking from the time I started to use it, as I smelled it long before the smoke was visibly pouring out the back. It was even on and striking arcs just seconds before shutting it down.

So thinking that it was just the caps and the 3 items (diode, igbt, voltage reg) on the heatsink on the PC2 input power board, I replaced the two large caps and those 3 items, inspected all components on the board, and used Miller Dynasty 200dx tech manual as a reference to test things they have in common.

She won't start up anymore. I can hear a faint humming noise, but no display. Looking at Power Module PM1 to be the culprit. Any other ideas before I test? Is PM1 easy enough to replace?

[cruizer]

Both mods are toast interconnect board is toast, possibly inverter board is toast as well. Usually caused by a improper hook up inside the machine, or primary's too squished inside of strain relief on machine.

replacing board individual components is completely useless. Think I mentioned this all before....

[cruizer]

With a tech manual, Im guessing you failed to do the preinspection procedures

[Careless]

We did the preinspection procedures. But using a Dynasty 200dx tech manual, not the Maxstar 200dx manual for this machine- as I do not have one.

When you say "boards are toast" what do you refer to? because we tested each individual component, and there is no burning on any of the boards, and all components check out individually.

Yes, my father went through practically each and every component except for the IC's. The PM1 seems to not be outputting any power at all to the test points (RC5, I believe).

Would replacing PM1 not fix the issue at all? is there no possible fix other than to replace all the boards? IF PM1 IS at fault, would that prevent the display from powering up?

[Irritantno9]

wow, this sounds rather familiar!

I hope you don't give up on this as I'd like to see you resolve this problem.

i would love to see someone come up with an open source welder that isn't so dependent on proprietary parts.

since your issue seems to mirror mine, I'll update as I make progress

[cruizer]

Well. no pre regulator, no go, go juice. Now the problem here is, that you guys are replacing parts on the boards. Replacing a cap after it has failed, should not get you too far, as these caps are over rated for thier use. So popping a cap means either an inrush of AC, or a over current of DC. Simply put, they don't up and fail.

Now some units have 2 mods, some have 1.

[Careless]

wow, this sounds rather familiar!

I hope you don't give up on this as I'd like to see you resolve this problem.

i would love to see someone come up with an open source welder that isn't so dependent on proprietary parts.

since your issue seems to mirror mine, I'll update as I make progress

What's wrong with yours?

[Careless]

Well. no pre regulator, no go, go juice. Now the problem here is, that you guys are replacing parts on the boards. Replacing a cap after it has failed, should not get you too far, as these caps are over rated for thier use. So popping a cap means either an inrush of AC, or a over current of DC. Simply put, they don't up and fail.

Now some units have 2 mods, some have 1.

This unit has one MiniSkiip Mod.

It's a 270 dollar piece (at the very least). I have found some used ones from other parts of the world for less than 10 dollars. They must be take-offs. At this point, I'd probably try a used one to see if it works.

I'm going to take a closer look at each part before I start replacing the PM1 or anything else. But up until the 3 screws on the board right after the power switch, I'm getting power. Those go to the Semikron Skiip as far as I can tell via the fat traces on the board, so If power is going in there, and not coming out... it's worth a shot to swap it out, me thinks.

[Irritantno9]

Well. no pre regulator, no go, go juice. Now the problem here is, that you guys are replacing parts on the boards. Replacing a cap after it has failed, should not get you too far, as these caps are over rated for thier use. So popping a cap means either an inrush of AC, or a over current of DC. Simply put, they don't up and fail.

Of course. I have never worked with a Semikron, and discussing it with someone else, we both decided that AC had gotten into this section. I don't have any idea what else it took out, but I have a load of patience

I haven't replaced anything other than two TVS. while something did cause the one TVS to fail, I replaced the other one due to destructive testing. ( I cut it loose from the board to isolate it.


The risk/reward ratio was in my favor. It still is. I don't have a lot tied up in this machine. Since I do almost no AC welding, I can afford to wait this out.

Might even hook my torch up to my golf cart battery pack and get get some scratch start time in.

I used to be in a welding business. With the exception of one welder tech I dealt with, all the others seemed to follow The Law of the Instrument.

[Irritantno9]

What's wrong with yours?

Same exact thing as yours.

Cap blew ( 450V 1500 uF) on sunday.

http://www.millerwelds.com/resources/communities/mboard/showthread.php?34087-Dynasty-200-SD-blown-capacitor

[Irritantno9]

This unit has one MiniSkiip Mod.

It's a 270 dollar piece (at the very least). I have found some used ones from other parts of the world for less than 10 dollars. They must be take-offs. At this point, I'd probably try a used one to see if it works.

I'm going to take a closer look at each part before I start replacing the PM1 or anything else. But up until the 3 screws on the board right after the power switch, I'm getting power. Those go to the Semikron Skiip as far as I can tell via the fat traces on the board, so If power is going in there, and not coming out... it's worth a shot to swap it out, me thinks.

If you can find one... I'd like to know the source. I have found some items, but not much cheaper than a new one.

[Careless]

If you can find one... I'd like to know the source. I have found some items, but not much cheaper than a new one.

I can see if they have two, and I can order one in and send it your way, just pay for shipping! I'll let ya know when I hear back.

[Careless]

Irritantno9, I sent you a PM regarding the SKiiP mods. Please let me know when you see it. Hopefully one of use can get these welders back up and running by changing a bunk module.

For the price that I'm acquiring them for, it's worth a shot.