Bought a new to me Airco Dip/Stick 160 multiprocess welder

[Aeronca41]

The capacitors SHOULD be discharged by a safety bleeder resistor that is part of every good circuit design. However, don't trust them. Just get an old screwdriver (dry) holding only the well insulated plastic handle (no wooden handled screwdrivers) and use it to short the bus bars and/or capacitor terminals together. Hold it there for a couple of seconds, pull it off, wait a minute, and do it again. The second time may not be necessary but I have seen occasions where some residual charge reappears. Not sure how or why but it does happen.

[Hondacivic247]

The capacitors SHOULD be discharged by a safety bleeder resistor that is part of every good circuit design. However, don't trust them. Just get an old screwdriver (dry) holding only the well insulated plastic handle (no wooden handled screwdrivers) and use it to short the bus bars and/or capacitor terminals together. Hold it there for a couple of seconds, pull it off, wait a minute, and do it again. The second time may not be necessary but I have seen occasions where some residual charge reappears. Not sure how or why but it does happen.

Should I unhook the wires that connect to the bus bar that connects all 3 ?

Sense there all connected on the bus bar will i need to do all 3 or will they all drain down if I just do one sense there all connected.. in the picture I posted you can see the Philips head screws that I will be grounding with the screwdriver and how there all connected.

In the background you see the diodes up high well one of them they look to be press fit I believe in the bridge there's a nut on one side and a wire rope that connects the other so would I just need to unhook the wire rope and leave it in to test those? Or will I have to pull them completely out?

[Hondacivic247]

Here's a good picture of the diodes on the rectifier

[Hondacivic247]

[Hondacivic247]

Also once the capacitors are discharged the diodes will be safe to handle or can they still hold a charge?

Sorry so many questions I've never worked on anything like this and I'm trying to learn and not die from not asking enough questions

[Aeronca41]

Should I unhook the wires that connect to the bus bar that connects all 3 ?

Sense there all connected on the bus bar will i need to do all 3 or will they all drain down if I just do one sense there all connected.. in the picture I posted you can see the Philips head screws that I will be grounding with the screwdriver and how there all connected.

In the background you see the diodes up high well one of them they look to be press fit I believe in the bridge there's a nut on one side and a wire rope that connects the other so would I just need to unhook the wire rope and leave it in to test those? Or will I have to pull them completely out?

No, don't unhook any wires before discharging the caps. You don't want to touch anything in there until after you ensure the machine is unplugged and you discharge the caps. {Keep your face/eyes a good distance away while discharging. We had a large capacitor (much larger than you will find in a welder) we used as a doorstop on one shop I worked in-- with a large screwdriver welded across the terminals. Needless to say the kid who was discharging it got quite a surprise-and some flying hot metal on his arm. Always be careful!}. You can just put the screwdriver (an old one) across the two bus bars, connecting them together with the screwdriver. That will discharge all the caps hooked to the bus bars. If there are other single caps somewhere else in the machine you can just short across their terminals.

To check the diodes just disconnect the braided cable; you only need one end of the diode disconnected to test it.

[Hondacivic247]

No, don't unhook any wires before discharging the caps. You don't want to touch anything in there until after you ensure the machine is unplugged and you discharge the caps. {Keep your face/eyes a good distance away while discharging. We had a large capacitor (much larger than you will find in a welder) we used as a doorstop on one shop I worked in-- with a large screwdriver welded across the terminals. Needless to say the kid who was discharging it got quite a surprise-and some flying hot metal on his arm. Always be careful!**. You can just put the screwdriver (an old one) across the two bus bars, connecting them together with the screwdriver. That will discharge all the caps hooked to the bus bars. If there are other single caps somewhere else in the machine you can just short across their terminals.

To check the diodes just disconnect the braided cable; you only need one end of the diode disconnected to test it.

Thanks for taking the time to explain I'm going to mess with the wire and feeder tonight before I did everything inside the machine

[Aeronca41]

Glad to help. I've received lots of help from this site-it's a great group of people. On the diodes-no, they will not hold a charge. Only have to worry about capacitors in that way.

[H80N]

Glad to help. I've received lots of help from this site-it's a great group of people. On the diodes-no, they will not hold a charge. Only have to worry about capacitors in that way.

Aeronca41
I am awfully glad to see another electroniker elbow deep in helping members diagnose & understand problems...
VERY COOL..!!....

[Hondacivic247]

I think my problem is the capacitors one read 2400 and another read 4700ish. I would assume they need to be 10,000.

The capacitors say

FAH 10000-50-C3
10000 MFD
50vdc
7726 CDE

My klein reader would say it's reading and then stop and say "Lo" , once I removed the leads it flashed the 2 readings I listed above.

I'm going to bring them to work tmrw and hook them up to a fluke multimeter to confirm as I bought mine used and want to double check to make sure it's close with the fluke

[Hondacivic247]

http://kaizerpowerelectronics.dk/theory/capacitor-code-table/

[Hondacivic247]

This explains the 7726 CDE code on it.

My meter starts it's reading in nF then changes to uF. It's not a u but you know what I mean.

[Hondacivic247]

Tested the 2 diodes on the one side of the machine I'm working on and they both are good. Had a reading of 375ish and only flowed one way and we're closed the other. I figured they were good cause the machine welds.

Does anyone know where I could find capacitors with the same rating incase mine are no good

[H80N]

Does anyone know where I could find capacitors with the same rating incase mine are no good

These are 10K uF @ 50WVDC right...??

Try Ebay

http://www.ebay.com/sch/i.html?_odkw...000uf&_sacat=0



BTW... you can use caps with a higher working voltage if need be... just NOT lower than 50WVDC..

[Aeronca41]

For capacitors check out Surplus Sales of Nebraska. (Surplussales.com). You might have to fudge some mounting details, and sometimes you just have to get the correct part if a generic won't physically fit, but often you can make it work without getting too kludgey. I've bought capacitors, relays, diodes, switches, fans, hydraulic parts, and who knows what else from those guys over many years and never been stung. I would check the caps when you get them but I've never had a problem. I think they have 10K MFD caps for $10-15. If my MM200 ever needs caps they would be my first try.

H80N, as I said earlier, glad to try and help. I don't have the welding knowledge many of you guys have; I think I know enough to know how much I don't know, made worse by what I've forgotten after being away from it for 25-30 or more years. But, I spent 50+ years fixing stuff and training maintainers ( both military and commercial) and many years (concurrently) in systems engineering, so there are some things I can help with. Ya do what ya can! I really value the amazing breadth and depth of knowledge here, coupled with the willingness to help people.