Author Topic: Water damage  (Read 446 times)

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Offline Audiorepair

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Water damage
« on: June 22, 2021, 09:15:30 pm »
Here is a rather sad photo of a digital piano mainboard that has water damage.
https://www.eevblog.com/forum/repair/water-damage-284182/?action=dlattach;attach=1229914;image

I'm really not sure I want to progress much further as this is a close-up.
https://www.eevblog.com/forum/repair/water-damage-284182/?action=dlattach;attach=1229916;image



The close-up appears to show the damage has got within the PCB layers?  Don't know, haven't really seen that ever before, but it looks like it has at least got under the solder resist.



Would be interested in anyones experience with this kind of thing.


(Sorry, I haven't yet learned how to put the photos in the correct paragraphs when posting)





« Last Edit: June 22, 2021, 10:08:42 pm by Audiorepair »
 

Offline MIS42N

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Re: Water damage
« Reply #1 on: June 22, 2021, 11:04:20 pm »
My limited experience is components will stand being dunked in water for a while. What are your options: 1. chuck it 2. try to fix it. I would submerge the board in clean water for a while. Use a soft brush to shift the gunge until it is clean. Dry off around 50 - 60 centigrade if you have some way of doing it (or a hair dryer and hope) until bone dry (a few hours). Leave it for a day. Do whatever tests you can to see if there are shorts. No shorts, power it up and see what explodes. You really haven't anything to lose except a few hours. I had some very old boards that had a rats nest built on them, along with rat poo. They cleaned up OK with a couple of components needing replacement. May not be representative as they were single sided with wide tracks. I have washed other boards successfully. Problems happen if tracks are corroded away (notorious RTC batteries on motherboards), hopefully your damage hasn't gone that far.
 

Online tunk

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Re: Water damage
« Reply #2 on: June 22, 2021, 11:32:20 pm »
Quite a few years ago I had a graphics card displaying artifacts.
I removed the heatsink and fan, and put it in the dishwasher.
I think I let it dry for quite some days before testing it.
It didn't fix the problem, but neither did it get worse.
YMMV
 

Offline NathanFulton

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Re: Water damage
« Reply #3 on: June 22, 2021, 11:54:52 pm »
I have fixed boards with leaked batteries and electrolytic capacitors that appeared this bad. This might be a little unorthodox, but here's what's worked for me on "lost" boards:

1. Dunk it in distilled white vinegar for a short amount of time, no more than 5 minutes, scrub the corrosion with a toothbrush. (Don't do this for too long because the vinegar will begin to eat other things than the corrosion...)
2. Soak it for twice as long in distilled water and/or ~70% isopropyl alcohol to neutralize the vinegar, dry it with warm air.
3. At this point, assess the damage. Look for traces on the PCB that are corroded all the way through. Do a continuity test between a few components to find out how bad it is.
4. You will definitely need to replace the capacitors. Re-flowing other components with fresh solder and lots of flux will help a lot of things. After that, it's trace-repair/bodge-wiring until it either works or you run out of patience.

Here's a good tutorial on fixing this kind of damage:


Good luck! :)
 

Offline Manul

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Re: Water damage
« Reply #4 on: June 23, 2021, 12:05:07 am »
It is sad, I agree. Once I spent almost half year repairing a water damaged device, it was a horrible experience. The worst things are: 1. corroded vias between layers, especialy if it is 4 or more layer board, 2. corroded, unmeasurable capacitors and resistors, 3. corroded (black) copper pads, which are very hard to clean and solder, 4. corroded or totaly lost BGA pads.

I would say clean it and look better under microscope. Test the board. If you see some of the signs mentioned earlier, better just search for a new board.
 

Online RoGeorge

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Re: Water damage
« Reply #5 on: June 23, 2021, 12:13:38 am »
how to put the photos in the correct paragraphs when posting

To embed the attached pics, first publish the post with the attachements (at the end), then click on the thumbnail pic so it goes big, then right click and copy the link address of the photo (when it's enlarged).

Once you get the link of the big photo, edit your post and insert (paste) that link in your message, and put the link between the tags [ i m g ] y o u r   p h o t o   l i n k [ / i m g ], or just select the pasted link and press the "Insert Image" button of the editor, like this:

Code: [Select]
[img]https://www.eevblog.com/forum/repair/water-damage-284182/?action=dlattach;attach=1229916;image[/img]


For the board, try to clean the are with a small brush or a cotton swab and IPA, maybe the internal PCB layers are still OK.  If not, replace the damaged components and rework each pin with wire-wrap.
 
The following users thanked this post: Audiorepair

Online Mario87

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Re: Water damage
« Reply #6 on: June 23, 2021, 10:47:12 am »
Oh! That looks horrible. Water damage is a pain to deal with, but first thing to do is clean it all up properly, dry it off in an oven and then re-inspect.

Here is an example of some water damage I repaired recently on a 2016 Yamaha R1 digital dash. Had to repair the traces, scrape away damage solder mask & repair and also get a new EEPROM as one of the legs broke off while being removed. Was a bit of a pain to repair the traces due to the pitch (0.65mm between centres & 0.3mm wide)

Luckily was able to use a bit of wire for the leg in the programmer and dump the data. Once a new EEPROM was obtained, programmed and re-installed it was drowned in an acrylic conformal coating to prevent the same happening in future.









 
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Offline Audiorepair

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Re: Water damage
« Reply #7 on: June 23, 2021, 05:52:47 pm »
Thanks for all the replies.

I have repaired water damaged stuff before, but maybe I didn't make my original post clear enough.


I cleaned off the horrible mess with IPA to see what was beneath, and it mostly showed things weren't actually that bad.
Until I took a look under the microscope.

What really concerned me was as the photo shows, around each via is a darker ring which looks like it might be inside the PCB.
Like somehow the water has got through the via and migrated into the PCB substrate itself.

If it has penetrated the PCB then I can't see justification for spending much time cleaning drying etc.

I dunno, maybe its just discolouration on the surface, but I thought someone might have been here before.


Thanks.





 

Online Mario87

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Re: Water damage
« Reply #8 on: June 23, 2021, 06:03:29 pm »
If you poke at that discoloured bit with fine tweezers does it start to move about or flake?

If it’s solid and hasn’t separated then I wouldn’t really worry. Is the board a basic 2 layer (looks like it could be) or more layers?

I would shove in the oven at 80c for a couple of hours, then let it cool naturally. That will remove all moisture from the board.

That’s what I would do first.
« Last Edit: June 23, 2021, 06:13:00 pm by Mario87 »
 


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