Little trouble with my argon

[bobhaha]

That mini LEM is looking like a good idea lol

I'm happy to drive 5 hours for a mini LEM... but I think we have more members in Sydney then you do down there...

I'll try make some time this week end to pull it apart and check it out. AUS it seems we will be in touch soon, with regards to the caps

 

[Things]

One of the things that was wrong with my PSU was a few exploded semiconductors. Your PSU is in a much better state in that it actually powers up, but maybe have a look at these 2 devices here and make sure they are OK:

 

[AUS]

I'm happy to drive 5 hours for a mini LEM... but I think we have more members in Sydney then you do down there...

I'll try make some time this week end to pull it apart and check it out. AUS it seems we will be in touch soon, with regards to the caps

Yep shoot me a PM about the caps.

Yes I'm happy to drive to Sydney. I'm flying there next week for work actually Won't have much spare time though.

We should organize something when it gets warmer. You are in Sydney, Mitch isn't far north of there, Lase is interested in coming down from Brissy too, and I'm sure we could find some others.

 

[bobhaha]

Well I got some time this morning to pull it apart. I found a lot of corrosion on most of the boards that deal with the 240V side of the power supply and the bottom board. I also found the nearest transformer to the interlock has rusty wires and is corroded.

But the biggest thing I found was some burn marks around one of the transistors leads on the bottom of the board. All the components on top of that look fine though and don't look like they have been replaced....

 

[Things]

That burn mark looks a bit suss. Is it from 1 of the devices I pointed out in my last image?


If so, the board I'm sending you has 2 brand new ones on it

The transformer lead on mine looks the same though.

Dan

 

[bobhaha]

Yup... mark is centered around these components...

 

[Things]

Got the equipment to test them? They're IRFBG30's IIRC.

 

[bobhaha]

What do I need? I have a DMM with an inbuilt PNP and NPN tester... is that all I need?

EDIT: UPDATE... I've put it all back together and now I when I measure the voltage across the filament output, I'm getting ~2-3Vac then it slowly drops to 0V within 1-2 seconds. I wasn't getting that before...

 

[AUS]

OK slowly dropping voltage usually indicates be a capacitor or resistor issue.

The burn marks on the board indicate overheating but not necessarily a fried comportment. I have seen boards get hot leave those marks but still work. Although its a sign something may not be right.

 

[Cyparagon]

Does your DMM have a diode test function? You can test those diodes that you boxed in-circuit.

 

[AUS]

You can kind of test MOSFET's with a multimeter too, at least it will tell you if they are open circuit or not.