Brymen 235 water damage (beer) - Page 1
Forum section: electronics / repair

author: Badams
author_rank: Newbie
timestamp: November 13, 2017, 12:29:26 am
content: Hey all,About a month ago I decided that I needed another multimeter for home projects and decided on the Brymen 235. Yesterday I went down to my local watering hole where they were having major issues with their P.A. system. I told my friend, a bartender there, that I'd spend a bit of my Sunday seeing if I could track down some issues. Today I went in, set my multimeter and some basic tools on the stage and started tearing into it, tracing cables and cleaning up the absolute tangled rat's nest that every bar venue sound system turns into. I was about 5 minutes into it when I had to do some acrobatic maneuver in between a tip-toed step and an awkward jump onto the stage, and sure enough I knocked a nearly full pint over onto my meter. Notice that I said nearly full: I was pretty sober, I promise!Anyway, now the meter is giving me "InEr" on any range other than mA/microA, even after letting the board sit in a bag of rice for a few hours. I'm looking for troubleshooting tips.I foundhttps://www.eevblog.com/forum/testgear/what-do-you-think-of-your-eevblog-brymen-bm235-multimeter/50/This thread which says:"Input warning detection uses a comparator inside main chip. While A or mA/uA input terminal is without being plugged-in by test lead, the compared signals are from battery voltage and from a fixed voltage around 3.6V. If battery voltage is more than 3.5V, that comparator may misjudge and display “InEr”."For now I'm going to keep letting it dry out while crossing my fingers, and take it to work tomorrow morning to begin probing around near the input jacks.

author: gnavigator1007
author_rank: Unknown
timestamp: November 13, 2017, 12:49:13 am
content: Rice isn't going to help. What kind of beer was it?

author: Badams
author_rank: Newbie
timestamp: November 13, 2017, 12:54:55 am
content: It was a cheap watery lager, probably Pabst Blue Ribbon.

author: gnavigator1007
author_rank: Unknown
timestamp: November 13, 2017, 01:03:35 am
content: Less sugary residue to clean off then. Give it a good cleaning with isopropyl alcohol instead of the rice. Might want to upload pictures too.

author: Badams
author_rank: Newbie
timestamp: November 13, 2017, 03:05:17 am
content: Bingo! Cleaning both sides of both boards with isopropyl did the trick.More proof that alcohol solves all problems, even those created by alcohol!Here's some information on the electrical conductivity of beer for fun (interesting to me because I do a lot of work in application-specific food industries):https://www.eolss.net/sample-chapters/C10/E5-10-01-02.pdf

author: IanB
author_rank: Super Contributor
timestamp: November 13, 2017, 03:21:05 am
content: For future reference, disassemble and wash boards and switches thoroughly with distilled or deionized water to remove contaminants, followed by a wash with isopropyl alcohol to remove the water. Keep liquids away from parts like LCDs that are not safe for washing.It seems IPA worked for you, but water is better at dissolving and washing away conductive contaminants and things found in watery substances like beer.

author: texaspyro
author_rank: Super Contributor
timestamp: November 13, 2017, 04:56:11 am
content: Geeze, guys... everybody knows you should clean beer damage with Everclear (190 proof grain alcohol) instead of isopropyl.I used to work where we had a Control Data 6600 computer with the 808 disk drives. These drives used a huge stack of 26" or so diameter platters. When there was a head crash the platter stack was remove with a crane and disassembled. The individual platters were then placed on a stand and cleaned... with Everclear. A little for the platter, a little for the techs, a little for the platter, a little for the techs, a platter for the little, a tech with a wobble.The head of the computer center used one of the platters as a coffer table. It didn't quite measure up to the 39" Bryant platters.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 13, 2017, 06:16:37 am
content: Quote from: Badams on November 13, 2017, 12:29:26 amI see the rice myth doesn't just apply to iphones ... From Jessahttp://mendonipadrehab.com/entries/general/rice-rantFrom Louis, but with more colorful language

author: GreyWoolfe
author_rank: Unknown
timestamp: November 13, 2017, 02:36:02 pm
content: Quote from: texaspyro on November 13, 2017, 04:56:11 amGood Lord! I once, in my misspent youth, took a slug out of a bottle of Everclear. I never made that mistake again. I lived in New Jersey at the time, the state where Everclear is made but is illegal to sell.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 13, 2017, 02:40:45 pm
content: If you ever have a spill, rinse the board with demineralized water or isopropyl alcohol. Be sure to do this while the spill is fresh, once things have dried, the problem and residu becomes significantly harder to solve.

author: CJay
author_rank: Super Contributor
timestamp: November 13, 2017, 03:16:45 pm
content: Quote from: Mr. Scram on November 13, 2017, 02:40:45 pmImportantly though, if it is at all possible, remove any power source from the device, the presence of power will accelerate corrosion.Then clean thoroughly with deionised water, pure isopropyl is a good way to flush water from under chips before you leave the board to dry.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 13, 2017, 03:34:40 pm
content: Quote from: CJay on November 13, 2017, 03:16:45 pmYes, I thought that bit was obvious, but it isn't quite. Remove power. Also remove any components that may be susceptible to water if possible, like a screen.

author: stj
author_rank: Super Contributor
timestamp: November 13, 2017, 08:51:22 pm
content: next-time drink the beer first.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 14, 2017, 11:20:07 am
content: Quote from: stj on November 13, 2017, 08:51:22 pmBeer that's already been drunk over your multimeter really isn't a good idea, whichever end it turns out to be.