Best way to clean a motherboard (to fix a possible short-circuit)

[Megaone]

I have this "open-bench" PC (by open bench, I mean the board and all the components were just laying on top of a desk) and it worked fine. A couple of years ago I stopped using it and just left the parts like that and never bothered to clean it so quite a bit of dust settled on top of it. Today I tried botting it up (after a quick clean of the components) and the system turns on but after a second or 2, shut down. This cycle keeps repeating. My guess is, with all the dust settled on the board, something is short-circuiting.

I've already used compressed air to blow the dust off the board but I wanna make sure nothing's shorting anything. I have a can of contact cleaner, can I just liberally spray it all over the board (including the PCI-E slots) and just wait for it to dry or maybe use a q-tip soaked in alcohol to go over the all the relevant bits? What do you reckon?

[IkeaGnome]

If it sat unplugged for those couple years I'd be looking for a CMOS battery before I assumed motherboard short.

[Megaone]

It sat plugged to everything and I doubt it's the CMOS battery, those things last for over 10 years. The board is like 5 years old. Not to mention a depleted CMOS battery wouldn't prevent the system from turning on

[manikyath]

household dust is msotly dead skin, which isnt conductive.

 

i'd say just reseat stuff or give every connection 'the industry standard wiggle'. depending on the age of the hardware a new cmos battery might not be a bad idea either.

[manikyath]

1 minute ago, Megaone said:

Not to mention a depleted CMOS battery wouldn't prevent the system from turning on

on some platforms it actually does. dont ask me which ones because it's WAY long ago, but i've seen it happen.

[Megaone]

hmm, maybe I'll just try again after blowing the dust off and reseating the cables

[Echothedolpin]

10 minutes ago, Megaone said:

It sat plugged to everything and I doubt it's the CMOS battery, those things last for over 10 years. The board is like 5 years old. Not to mention a depleted CMOS battery wouldn't prevent the system from turning on

Depends on the manufacturer, but older systems wouldn’t boot without a working battery. I’ve seen it on mostly OEM boards.

Some were no older than five or six years.

 

Might not be the problem if you have a non-OEM system, but it’s a fix that only takes a couple sense to try.

[mariushm]

8 minutes ago, Megaone said:

It sat plugged to everything and I doubt it's the CMOS battery, those things last for over 10 years. The board is like 5 years old. Not to mention a depleted CMOS battery wouldn't prevent the system from turning on

They last 10 years IF your computer is connected to a power supply that supplies motherboard with 5v stand-by ..  then 5v stand-by is used instead of the battery to keep the CMOS settings fresh, and the battery sits unused.

In a box, it's 2-3 years, maybe less. A battery is cheap, replace it.

 

If you want to clean the motherboard, get some isopropyl alcohol (doesn't matter what purity, but if it's less than ~97% you'll want to wait for the water to dry out) , put the mobo in a plastic box  and pour a bunch of isopropyl alcohol on it, and shake the box so that alcohol gets everywhere. If you want, use a soft brush to wipe surfaces.

After a few minutes of agitating the alcohol, you can take out the motherboard and put it somewhere warm to dry out. Remaining alcohol will evaporate fast... if it's less than 97% (ex. you should be able to easily find 70%-ish because that concentration is very good to kill germs/bacterias on hands) you have to wait for the 30%-ish distilled water to dry out.

 

[Megaone]

Hey guys, just a quick update: I tried again after just blowing the dust off and it worked. Although I found out the problem wasn't the dust nor the battery, it was the GPU not being fully slotted into the board. I have it on top of a piece of fairly sturdy foam (for height) so when I slotted the GPU, it flexed a bit and didn't go all the way in. I figured it out because I tried slotting it again but this time I put my other hand under the foam/board for extra support and then the system turned on just fine

[Echothedolpin]

3 hours ago, Megaone said:

Hey guys, just a quick update: I tried again after just blowing the dust off and it worked. Although I found out the problem wasn't the dust nor the battery, it was the GPU not being fully slotted into the board. I have it on top of a piece of fairly sturdy foam (for height) so when I slotted the GPU, it flexed a bit and didn't go all the way in. I figured it out because I tried slotting it again but this time I put my other hand under the foam/board for extra support and then the system turned on just fine

Glad to hear it was an easy fix! Good work figuring it out

[Megaone]

3 hours ago, Echothedolpin said:

Glad to hear it was an easy fix! Good work figuring it out

Actually I don't think that was it either lol. I think the system does that whole power on/power off cycle a few times every time you plug a GPU into a system that has had a previous GPU plugged in. I say this because after I "fixed" it by "reseating" the GPU, I then switched to a much older GPU (which I made sure was properly seated) and it still did that. Except I just waited and after a few on/off cycles, it then turned on for real and booted into Windows normally without me touching it.

 

Keep in mind that I switched a 3080 (with the latest drivers installed) for an old 8500 GT, which obviously can't even use those drivers. Maybe that was the reason. The system was probably like "da fuk did you just plug into me??" so it did that on/off thing until it got "acclimated" lol. That's my guess anyway

[ExalyThor]

Sounds crazy, but just take an old toothbrush and go to the sink. Brush the board with dish wash. You can even clean an lga socket with the toothbrush. The lga pins are more rigid than people give them credit. After you're done blow the board with an air compressor to get rid of all the water. Let it dry for at least a few hours. Your board is now as clean as new.