Can you short a motherboard with ethanol?

Thread Starter

rambomhtri

Joined Nov 9, 2015
397
Hi, so I had this falling apart laptop and I wanted to repair it. First thing I did was take it apart and clean it thoroughly, using ethanol 96%. I applied ethanol to the mobo with the help of a toothbrush and rubbed, as it was kind of dusty and dirty. Then, after cleaning it, I used a hair dryer to evaporate the probably already evaporated ethanol, had the motherboard naked over the bottom case/chasis, connected all the cables and everything, naked/without the rest of the case, and proceeded to turn it on. It turned on and was working fine, the laptop screen as well as the external monitor via HDMI, so I shut it down.

Today I noticed the HDMI port was kind of rusty and dirty as well (green and brown stains here and there), so I poured ethanol in the hole and rubbed. I poured it vertically, so the excess of ethanol run all the way through the motherboard, although there was "only" the RAM slots in the way. They could have soaked a little bit, or not, I don't know. This time I hadn't the hair dryer accessible so I blew a little bit the area, which evaporated whatever I could see quite quickly. Waited for a few minutes and tried to turn it on. This time, it's not responding at all. I've checked for 30 min every cable and the plug and everything, nothing, no sign of life.

So, my first question is... can you short the mobo by deep submerging it in ethanol?
If the answer is "no, ethanol 96% can not conduct electricity at all, you can literally put a turned on PC inside an ethanol tank and it will work fine", then I must look for the solution. If the answer is "yes, if it wasn't gone and you did not dried it properly, it's possible you short it", well, I could be the idiot of the month.

I've checked the volts, 20V on the motherboard itself, so it's being fed. I've reset the BIOS battery. Don't know what else can be. May be some weird security circuit that closes if you have the case on or something?
 
Last edited:

Thread Starter

rambomhtri

Joined Nov 9, 2015
397
Update: checked the power on button itself, works fine, so it's not a faulty button...

I've also read that, since ethanol does not contain any electrolytes, then it can't conduct electricity. Is that right? Is there any exception such us "it could have mixed with the dirt and that could conduct"?
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
397
Kinda rusty HDMI port means it was a little green here and there, and brown here and there, but it was working fine because I tested it the first time. I just wanted to clean it as good as I could. Besides even if I broke the HDMI port, which I have not at all, the laptop would not be totally dead.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
397
Update: after waiting for 20 min, kind of expecting to have shorted some thing like a total dumb, I have tried it again and BOOM, worked. What in heavens is going on... If it does not respond after everything I did, clearing CMOS, remove battery, etc... It would be safe to say something shorted and it's not turning on. But this nonsense of waiting and fixing itself... Wth
 

ThePanMan

Joined Mar 13, 2020
83
Cleaning a board doesn't mean dissolving contaminants, it means flushing them from the board. If you wash the board and simply move the "dirt" elsewhere, you can end up with a short. Ethanol is not conductive. However, the contaminants suspended in the ethanol, contaminants from the "rusty" USB port ARE (or can be) conductive.

An experiment I saw when I was maybe 5 or 6, an electrician took a bucket of water and a 120 volt test lamp and stuck the two leads in the water. The bulb did not light. But after sprinkling a pinch of salt in the water, when the probes were stuck in the water the light bulb lit. The water with salt acted like a switch, turning the light bulb on. It wasn't the water, it was the contaminant - salt - in the water that made it conductive. So if you clean a board with ethanol you have to do more than evaporate the ethanol. Doing so you leave the contaminants behind to short something.

The fact that it's working now suggests it's possible you had a connector that was holding some dirty ethanol.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
397
Oh, I know, I just didn't pour ethanol right on the dirt and dust and let ethanol become black and spread all over the board. First, the board was already clean, I did it some days ago so it was pretty much new. However, I forgot to clean the ports. All were fine except the HDMI which had dust, dirt and some green and brown layers here and there. I first cleaned it dry with a brush, and when there was nothing else that a brush could clean, I poured the ethanol on there. Hence, if it went to the other side of the mobo it was pretty much clean, I guess. My question really was, just to make sure...
Can you submerge a PC in ethanol? (Forget about fan flow)
 

AlbertHall

Joined Jun 4, 2014
11,498
If it is 96% ethanol that means it is 4% not ethanol. What is that 4%? Water?
When ethanol evaporates it will get cool and possibly attract condensation of water from the air. Water evaporates more slowly than water. As stated dirty water can be conductive. It sounds like you did not get enough drying to get rid of all the water. Parts of a mobo circuit are quite sensitive to stray conductive paths which are not short circuits but even quite high resistances can disrupt the circuit.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
397
I looked for that but it does not show in the bottle what's that 4%. It only says 96% v/v. May be it's water, but with that much ethanol the mix will evaporate so quickly.

Is that right?
I thought that the moment something does not turn on due to liquid spillage, the chances of short and dead mobo are like 99.99% compared to "it only caused high resistance here and there that somehow avoided the correct function".

I mean, I can understand if you spill something in the power on button area, you could temporarily avoid a connection that turns it on, but "general" spilling over a motherboard that causes it not to turn on?
Sounds weird, I don't know.
 

AlbertHall

Joined Jun 4, 2014
11,498
Yes a very little water can stop proper operation. On a mobo there will be some BGA chips. These have many connections underneath the chip in a very narrow gap. Liquids will get under there by capilliary action and because very little of the that liquid is exposed to the air it will only evaporate slowly.

Any time you put any liquid on an electronic circuit you need to allow plenty of time to be sure it has all evaporated. For wet mobile phones it is usually recommended to leave it in a bowl of uncooked rice for two days to allow it to 'suck' out the water.
https://tinhat.co.uk/blog/how-fix-water-damaged-phone-8-simple-steps
 

Yaakov

Joined Jan 27, 2019
3,482
96% ethanol is denatured. That is, adulterants are added to make the alcohol unfit for human consumption. It is general sold as a fuel, and is a terrible choice for electronics because some denaturants are incompatible with materials used, such as acetone.

If you need an alcohol solvent, use 99% isopropyl alcohol (IPA, isopropanol). Keep in mind, this is not anhydrous, that is, it does contain some water—albeit a very small amount. Because of this, thorough drying is advisable, though it doesn’t take long because the water is very little of the volume.

Distilled water is an excellent solvent for electronic use as long as it is thoroughly dried afterwards. Water is a solvent for things that alcohol will not touch and vice versa. Warm air is an excellent way to dry things and works very quickly.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
397
Thanks for the advice... I am really shocked about what you said about ethanol. I've been using it to clean all kind of electronics (mostly motherboards from PCs, laptops, CPUs...) all my life. Well, not ethanol, but whatever I had in my bathroom: alcohol, ethanol, etc... I mean, I very rarely pour a liquid like that on a motherboard, it has to be a really dirty mobo with green stuff that a brush just can't get through, like this time.

Ethanol works fine unless it has acetone on it, right?
 

Yaakov

Joined Jan 27, 2019
3,482
Thanks for the advice... I am really shocked about what you said about ethanol. I've been using it to clean all kind of electronics (mostly motherboards from PCs, laptops, CPUs...) all my life. Well, not ethanol, but whatever I had in my bathroom: alcohol, ethanol, etc... I mean, I very rarely pour a liquid like that on a motherboard, it has to be a really dirty mobo with green stuff that a brush just can't get through, like this time.

Ethanol works fine unless it has acetone on it, right?
Ethanol is not used as an electronics solvent, isopropanol is. Things on boards are not necessarily insoluble in ethanol. I would never use it in the way you are doing. Stick yo 99% IPA. The 70% is 30% water and will not evaporate quickly.

It will only take one case where there is something unexpected on the device for ethanol to ruin your day.
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
397
Totally, thanks! I've looked it up and I've been using this one brand of alcohol 96% almost all the time, but sometimes I had ethanol and they looked and worked exactly the same. Good to know I should avoid ethanol if possible.
 

shortbus

Joined Sep 30, 2009
8,803
can you short the mobo by deep submerging it in ethanol?
The usual problem with ethanol and computers is it short circuits the person using it.
"As a central nervous system depressant, ethanol is one of the most commonly consumed psychoactive drugs.[31]

Despite alcohol having psychoactive properties, it is readily available and legal for sale in most countries. However, there are laws regulating the sale, exportation/importation, taxation, manufacturing, consumption, and possession of alcoholic beverages. The most common regulation is prohibition for minors" From - https://en.wikipedia.org/wiki/Ethanol#Recreational
 

SamR

Joined Mar 19, 2019
3,484
Several folks here have mentioned using a dishwasher to clean boards. I would use a detergent such as Alconox instead of regular dishwasher soap or just leave it out and stick to a water wash and dry.
 

Tonyr1084

Joined Sep 24, 2015
6,253
I have used AND DO NOT RECOMMEND lighter fluid. It works. But I don't recommend it because you never know what it may attack. Automatic transmission fluids are recommended for particular transmission types because some fluids in the wrong transmission will attack plastic parts. Some devices with plastic covers or screens state that you should NOT use certain types of cleaners because they will attack the plastic. And I've learned that lesson the hard way when I got some spray chemical on a plastic surface and turned it white.

My wife decided one evening to deep clean the microwave oven. After the deep cleaning it didn't work. She used Simple Green and it definitely dissolved the grease, but the dissolved grease ran down onto the control board. She was very upset and thought she would have to buy a new oven. I took it out in the garage and washed it down with 91% Isopropyl Alcohol, then blew it dry with an air hose. Put it back in the oven and it worked.

One doesn't always have the right cleaner at hand. Substitutes will work but may not be recommended. Proper cleaners are available; but the board construction is also a part of the equation. Some board manufacturers (and companies who utilize them) may specify use of a "No Clean" flux. Meaning you don't clean the board after manufacture. Some fluxes are "Water Soluble", meaning you clean the board with De-Ionized Water. Tap water contains lots of minerals that can be conductive. Then there's rosin fluxes that need to be cleaned or they will continue to degrade the board and solder joints. We USED to use MEK (Methyl-Ethyl-Ketone). But with the nature of MEK, Cirrhosis of the liver was a serious concern. We switched to something called "Safety Kleen", but on the label it said "Warning may cause death if inhaled". Then we switched to spray cans of "Alcohol-Freon" (I think - it's been many years since then). There are a wide variety of cleaners out there and various fluxes that will or will not clean depending on what you use to clean them. For now, your alcohol has done the job. Be glad there was no (apparent or immediate) damage.
 

BobaMosfet

Joined Jul 1, 2009
1,848
Ethanol is not used as an electronics solvent, isopropanol is. Things on boards are not necessarily insoluble in ethanol. I would never use it in the way you are doing. Stick yo 99% IPA. The 70% is 30% water and will not evaporate quickly.

It will only take one case where there is something unexpected on the device for ethanol to ruin your day.
Ethanol can also dissolve protective finishes, sealants etc, and soak into things like capacitors, etc. Never ever _dip_ a PCB into a solvent. If one finds that things are now oxidizing (aka rusting), it means you may have removed a protective varnish.
 
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