Ask HN: How to deal with a possibly liquid-damaged monitor?

1 pointsby RGammavor 3 Jahren11 comments

Greetings,

yesterday a small liquour-filled rack detached from the wall and a bottle of sugary liquour crashed on my SO's monitor (recent AOC 28" 4k panel).

The frame split cleanly open and a few ml of liquid spilt through the ventilation grate on the controller board and internal PSU.

Instantly pulled the plug (it was on standby), and turned it on its head which seemed to have prevented worse. On first inspection the panel doesn't seem to have cracked or sustained liquid damage, but I'm worried about the PSU. Searching online I could find quite a lot about cleaning "regular" PCBs, but nothing about PSU components (seems to be forbidden territory).

Pictures, bad quality I know:

PSU front: https://ibb.co/JnLpf67 (a few splodges)

PSU back: https://ibb.co/0rH65HG (most visible gunk)

Controller front: https://ibb.co/BgxhSpT (some gunk here too)

The controller back looks pristine.

The panel power supply port (top of first picture) has stuff in it as well. My plan is to carefully clean with 99% isopropyl alcohol on a Q-tip and a tooth pick for the hard to reach places, e.g. inside the connector, followed by hair dryer treatment. I read some soak it, but that might not be a good idea with the coils, foil and all and is probably overkill.

Then I would stress-test it for a few hours in the yard and see if it goes up in flames.

Do you think this is a sane way to handle this? Any (longer-term) failure modes I should be aware of?

I would be sad to throw it away since it's quite new and expensive. Thanks in advance.

12 comments

jaclazvor 3 Jahren

Usually the "forbidden territory" about PSU's is only about the fact that they are (were) connected to mains, if you give the PSU the time to let the capacitors discharge (a few minutes in the worst cases) they are perfectly safe.

What I would do would be to wash it with distilled (or demineralized) water first.

If the gunk goes away, there is no need to use the isopropyl alcohol at all, but otherwise a quick immersion in isopropyl is also ok.

Both with distilled water and isopropyl alcohol, I would find a suitably sized container and put in it just the right amount of liquid to cover the part(s) where the gunk is visible (the top right connector in your case).

Distilled water won't do any damage and you can leave the PCB in it as long as you want (to give it the time to moisten/dissolve the sugary gunk), with isopropyl alcohol there won't be any damage to the actual components, but if you keep it for long you may well have some esthetic damage (like discoloration of some plastic).

There should be isopropyl alcohol available in spray cans too, I wouldn't go for contact cleaners if not for the actual connector pins, after they are cleaned, at least the types I am familiar with do leave a (protective) residue that is good on the actual connectors, but that you don't want elsewhere on the board.

RGammavor 3 Jahren

I ordered this one now: https://www.weicon.de/en/electro-contact-cleaner-cleaner-for...

Judging from the product pictures, it seems to be safe to use on the entire board. Will let you know what happened :)

jaclazvor 3 Jahren

Yes, that one is (from its specs sheet) only a mix of (volatile) solvents, it should not leave any residues after evaporation.

RGammavor 3 Jahren

Monitor is working again. I could remove most of the gunk with the weicon cleaner, Q tip and an old toothbrush. There's still some white non-sticky residue left in some places, but it seems to be harmless.

The panel was damaged by the impact, but it's not too bad. Whew!

anenefanvor 3 Jahren

I've used isopropyl but as a fast flush to remove a quantity of moisture / water, followed with a prompt drying with a blast of air. Isopropyl will actually absorb moisture from the air so sometimes it's not an ideal choice for boards that are already dry and there's no access to compressed air via an earthed (ie human skin contact who themselves are grounded) steel nozzle.

Note, isopropyl does not agree with some plastic surfaces or finishes.

Probably I'd suggest using a quality electrical contact cleaner, which usually is available as a pressurised spray pack. Generally they're designed to dry residue free, some offer contract cleaners offer a protective coating as well.

RGammavor 3 Jahren

Thanks for the suggestion. A quick search turned up https://www.weicon.de/en/electro-contact-cleaner-cleaner-for... and https://www.canford.de/Products/55-101_KONTAKT-60-Electrical...

Will order one or the other and use that instead then.

jaclazvor 3 Jahren

That kontakt 60 is not good (it is one of those that leave the protective layer).

I found some reference on how it is recommended to use the Kontakt WL to clean the residues of the Kontakt 60:

http://www.kontaktchemie.com/koc/KOCproductdetail.csp?produc...

So you want the Kontakt WL and not the 60:

http://www.kontaktchemie.com/koc/KOCproductdetail.csp?divisi...

[deleted]vor 3 Jahren

pr07ecH70rvor 3 Jahren

Isopropanol should befine.

Some years ago I did something similar on my DELL monitor, but with coca cola. Cleaned everything with isopropanol, let it dry for a day just to be on the safe side, and tested. It still runs even today. PSUs are robust.

RGammavor 3 Jahren

Good to know. I'm most afraid of missing something, it liquifying and shorting the PSU. Guess I'll be extra thorough.

imaginarycodervor 3 Jahren

Usually that’s not random, how in the world did you manage to do that? All the best.

RGammavor 3 Jahren

Wasn't in the room when it happened. The cheapo shit shelf (not my buy btw) couldn't hold the sixth bottle. We were lucky it was just the one that broke!