Testing motherboard - how much assembly?

[richk]

I am working on a problem where a small amount of water got onto a motherboard. Before I throw the old one away, I want to try to clean the mess and see if it will work. It's obvious where the water was (4 small places on the underside). The laptop sat in a puddle after water got onto the table where it was sitting. I cleaned up the stains with alcohol and a Q-tip and I want to know how much assembly is required before I can see if any lights come on. (Before I worked on it, there were no lights and no beeps) If I attach the battery, video cable and the power cord, is that enough to get the charging light? Do I need CPU? Memory? Anything else?

[kchung]

I worked on a T41 at my work that had some tea (luckily no sugar or cream in it) spilled in it. I don't know if any tea got under the motherboard but after dissaembling much of the laptop and letting air dry for 3 days, it started working again.

I removed everything possible, taking care to wipe up any visible water as I went along.

Removed power sources, took out hard drive immediately, took out CD Rom, took off keyboard, keyboard and touchpad bezel, opened the RAM Bay and took out both RAM chips, the PCMCIA slot assembly. I was pretty sure the liquid was only on the top the mobo. I also took the shielding off the hard drive to make sure no liquid hit.

At this point I put the laptop on it's side with the lid open and left the system for 3 days. My work is air conditioned, so the air is fairly try so I'm sure that helped get rid of any left over liquid.

Re-assembled and it worked fine.

To get the charging light you would need the battery but I doubt anything else.

However my recommendation is that you air dry the system for several day and using an air duster (canned air), try to see if you can get any water to be visible. I recommend you shoot the air from the keyboad side of the mobo with the laptop on paper that will clearly show if any water comes out. If any water does come out, wait a few more days before applying power.

Good luck!

[carbon_unit]

The last one I seen with liquid damage had puddles between the motherboard and the lower case. If the owner had actually removed the motherboard and cleaned it up the motherboard would have been OK, but they only removed the keyboard and cleaned what they could see. Bad mistake.
I could see the burn marks on the insulator sheet after I removed the motherboard.

[Lazarus]

I could not agree more (out of my own painful experience) that its seldom the water you see that hurts you, but the one you don't.

So I highly advise you to go to e.g. Fry's and get yourself some
water displacing cleaning fluid, it is specially designed to clean electronics (might not be to healthy to be used indoors).
They used to use Fluor based compounds for that, but I think that changed for environmental reasons.

In any case, you should drench the equipment in the cleaning fluid, then use an air duster to get as much of both liquids out as possible and then thoroughly dry the rest (e.g. with a hair dryer).

DO NOT JUST LET THAT WATER DRY ON ITS OWN!
The corrosion damage would be worse than anything a short circuit could do, because to be honest at 12V water is a lousy conductor.

*After* that you can put the components back together, one after the other.
You will need a CPU to boot of course, and also some memory.
All else is optional. You should also connect the display, but not the hard disk or CD/DVD at this time.
Be careful with the power supply. If you don't use the battery make sure your power supply did not get wet, too.

In any case, I found its easier to pull the plug of the power supply in case anything goes wrong (as the off switch function is no longer a mechanical one, but controlled by the motherboard's firmware), then trying to pull the battery out a Thinkpad while the sparks are flying

[richk]

Corosion seems to be what I have. The original owner took it to a dealer right away who said you need a new motherboard and put it back together. It sat for a month without any cleaning. After I cleaned it up, I cannot see any obvious problem, but I get no power lights. I checked all the fuses I could find. I'm not sure if it is worth any more of my time.

[Lazarus]

Corosion seems to be what I have. The original owner took it to a dealer right away who said you need a new motherboard and put it back together. It sat for a month without any cleaning. After I cleaned it up, I cannot see any obvious problem, but I get no power lights. I checked all the fuses I could find. I'm not sure if it is worth any more of my time.

Those are multilayer motherboards and if the corrosion damaged even a single layer, your whole MB is shot.

You might also have a bad connection in any of the many sockets of your system, preventing circuits from properly initializing, a single Diode that doesn't switch correctly can mess up your whole day.

You need a volt meter and maybe also an Oszillograph and measure that board through to see if the CPU gets power and the correct clock speed.
W/o that all else is in vain anyway.

If no layer has been damaged, you might still combat the corrosion with the forementioned (strong) cleaning fluids.

But don't get your hopes up. My own experience is that water damage can be almost totally prevented if treated aggressively right away.
But its a lost cause after just a few days.

I once had some keyboard that got water/coffee spillage.
The ones I treated right away, I could safe.
The ones that lay around for even a few days were all lost causes.
Even after I managed to clean up the mechanics and repair the damaged connections, something still didn't work right.

There's a reason why they assemble that kind of stuff in clean rooms - dirt kills electronics faster even faster than heat does.