Waterlogged Scrap Recovery

[nymetropolitans]

So here's a pretty boneheaded maneuver I pulled a few months back...

I found a Dell Dimension 8200 that looked to be in decent shape sitting on a curb one day, brought it home, plugged it in and nearly electrocuted myself when enormous sparks started flying out of the power supply.

I completely forgot that it had rained the night before....crapola. It's been sitting in a closet since then because honestly, after that experience I'm scared to even touch it! I had planned all along to just salvage the CPU and DVD-ROM for a transplant into another machine. Is it possible that these components are still working after I fried the P/S? I'm not really that familiar with PC power supply construction, but I would assume there is a fuse or some kind of circuit breaker between it and the motherboard connector that should prevent voltage spikes like the ones caused by an idiot plugging it in wet from reaching the more sensitive stuff....or I'm hoping at least??

Anyway, my real question is this: is it safe to pull this stuff out and try it in another machine (especially the CPU) without risking damage to any parts of that non-fried PC? Common sense tells me it's fine and the worst that will happen is that nothing works, but these parts are going into my main computer and I can't risk really screwing it up....so I have to ask on here, like a wimp

 

[channelmaniac]

Take an ohmmeter and check the resistance from +12 and +5v to ground. If it's not shorted then power it up without the data cables connected. If no smoke comes out then give it a try.

RJ

 

[Chuck(G)]

Make sure everything is dry, dry, dry. Water can hide in the darnedest places on a PCB and make your life less enjoyable if you apply power to it.

Compressed air can help to force some of it out.

 

[DimensionDude]

I deal with waterlogged electronics on a daily basis (food processing plant that requires daily washdown).

My most used tool is a hair dryer. Components generally can take a lot of heat as long as they aren't powered up. I also use an aerosol contact cleaner to force the water out of hiding, following that with a shot from the blow dryer.

Indeed, some may find it a bit odd to see a $250,000 machine being "repaired" by someone wielding a hair dryer.

Just as an aside, I didn't kill the power to a weighing/packaging machine before spraying one of the load cell pre-amp boards with contact cleaner. When the resulting frost melted and bridged the 30vdc power, it was quite spectacular.

Kent

 

[nymetropolitans]

Alright let me get this straight, are you guys telling me to test the components in the PC with the power supply I exploded? Do you think that would be safe? I seriously doubt it'll even turn on....the smell in the aftermath wasn't pleasant.

I just wanna pull out the CPU and DVD-ROM....just wondering if that was safe, or if it was likely the exploding power supply had damaged other parts in the PC.

Maybe I'll try plugging it in anyway....what the heck! :mrgreen:

 

[Unknown_K]

If you actually smoked the PS I would not even bother trying it since I would expect it to blow up any day.

Try the other parts in a different machine to see if they work and use them.

How nice is the case? I have the PS and motherboard/cpu for a Dell Dimension 8300 but no case. So if you are going to gut it and toss the tower case any chance I can snag it for shipping (I would just need the case, mounting rails, and the fan/shroud that goes over the cpu.

 

[nymetropolitans]

If you actually smoked the PS I would not even bother trying it since I would expect it to blow up any day.

Try the other parts in a different machine to see if they work and use them.

How nice is the case? I have the PS and motherboard/cpu for a Dell Dimension 8300 but no case. So if you are going to gut it and toss the tower case any chance I can snag it for shipping (I would just need the case, mounting rails, and the fan/shroud that goes over the cpu.

Yeah, I'm just being a wuss thinking plugging this possibly screwed up CPU into my main PC is somehow going to mess it up. The more I think about it the more retarded I sound.

The Dell is actually a Dimension 8250, but I'm like 99.9% positive its the same case as the 8300. I'm gonna pull everything out of it tomorrow, the case is in good shape - after that it's all yours! I'll send you a PM tomorrow night. The plastic enclosure is a little loose fitting, but I'm pretty sure they're just built that way. It's one of those cases that comes apart like a freaking Transformer or something. Took me a half hour to figure out how to open it

 

[Druid6900]

Turn it on. What do you have to lose?

I have an Apple /// that I work on, from time to time, and, once, after about 10 years, I turned it on and smoke came pouring out of the supply but it started up.

Turned it off for a couple of hours, turned it back on, a little more smoke and that was it. It was burning 10 years of accumulated dust off of the PSU.

 

[Unknown_K]

I have heard that you can blow a tantalum capacitor on a motherboard (loud pop and smoke) and if it was not doing anything too important the machine will keep on running like nothing happened.

 

[Unknown_K]

Yeah, I'm just being a wuss thinking plugging this possibly screwed up CPU into my main PC is somehow going to mess it up. The more I think about it the more retarded I sound.

The Dell is actually a Dimension 8250, but I'm like 99.9% positive its the same case as the 8300. I'm gonna pull everything out of it tomorrow, the case is in good shape - after that it's all yours! I'll send you a PM tomorrow night. The plastic enclosure is a little loose fitting, but I'm pretty sure they're just built that way. It's one of those cases that comes apart like a freaking Transformer or something. Took me a half hour to figure out how to open it

Thanks.

Dell used the same cases (with a little change here and there in the plastics) for a long time. I hate how the motherboard is connected to a metal plate that only fits their cases, and the I/O bezel is part of that plate (and it looks like a custom arangement to boot).

Those lime green mounting rails (if that unit uses them) are also a pain to find. And they have those special cables to turn the unit on along with routing usb to the front.

 

[chuckcmagee]

On the tants, I just go in with diagonal cutters and chop off the remains first. I have found the charred remains like to continue to short out, so chop and power on. My exploding smoking tant count is now 6, getting almost boring.

 

[Micom 2000]

Make a test circuit from an old power cord and a light-bulb socket. Cut one side of the cord and put an alligator clip on each of the resulting ends. Screw in a !00 watt bulb. This becomes a handy fused circuit. Just attach the alligator clips to the neg. and pos. circuit you're testing and switch on the bulb. The bulb wll pop before you do any more damage.

Lawrence

 

[chuckcmagee]

Make a test circuit from an old power cord and a light-bulb socket. Cut one side of the cord and put an alligator clip on each of the resulting ends. Screw in a !00 watt bulb. This becomes a handy fused circuit. Just attach the alligator clips to the neg. and pos. circuit you're testing and switch on the bulb. The bulb wll pop before you do any more damage.

Lawrence

Sad but true -- we go through life, amassing all this valuable knowledge. Then, dead. They do say that the internet is forever. One day, 80 years from now, an internet search will find some of our tricks. Small consolation, I suppose. On the other side, we do have websites going down and staying down after that every day.

 

[Unknown_K]

The internet is not forever. How many people posted drivers and fixes on compuserve expecting them to be around for ages? Where are all those things now?

There are plenty of websites that are not that old but are gone, their contents lost forever because the owner excluded the site from googles spiders (robots.txt).

I have also noticed newsgroups such as sci.electronics.repair has posters who make sure their post expires and is not archives, so they can help a specific person with their issue but the knowledge will expire in a few weeks as the post is removed.