Message-ID: <247@ssc-bee.UUCP>
Date: Thu, 18-Oct-84 16:31:47 EDT
Article-I.D.: ssc-bee.247
Posted: Thu Oct 18 16:31:47 1984
Date-Received: Sun, 21-Oct-84 14:04:48 EDT
Distribution: net
Organization: Boeing Aerospace Co., Seattle, WA
Lines: 170
Thanks to all of those who replied to my help for cleaning circuit boards:
"My Apple motherboard has gotten quite dusty from
running without the top, and I suspect oxidation
has occurred to some of the socket and chip contacts.
I want to clean up all the contacts. Is it safe to
immerse the whole board with all chips, resistors,
capacitors, etc. in place? If so, what cleaning
agent is recommended? Is it likely to help?"
I was quite surprised at the different methods of cleaning available.
Here is a one line summary of each method (ranked in approximate
difficulty/risk):
1) If it ain't broke, don't fix it!
2) Vacumning/compressed air.
3) Remove all chips; clean contacts with ink eraser.
4) Freon bath; air dry.
5) Soap and water bath; air dry.
6) Hutto's Blue Dip Industrial Cleaner (bath?).
7) Freon, soap and water, or alcohol bath; *** oven dry ***.
The text of most messages I received follows. (My apologies to those who
replied, but are not represented below. I seem to have lost a few
messages.)
===============================================================================
> From ssc-vax!uw-beaver!cornell!vax135!houxm!ihnp4!zehntel!hplabs!hao!seismo!harvard!wjh12!genrad!decvax!decwrl!dec-rhea!dec-dosadi!binder Sat Feb 5 22:28:16 206
> Subject: Re: How do clean motherboards?
> IF IT AIN'T BROKE, DON'T FIX IT! Think about it: If a machine or board
> is working properly, nothing you do to it is likely to improve the
> situation. So don't risk immersion in solvents or physical manipulation
> to clean contacts. Even gentle manpulation can break component leads,
> and many solvents leave behind worse deposits than they remove.
> However, dust and various airborn grime definitely can be deleterious to
> boards. First, dirt can attract or retain moisture, leading to
> corrosion as well as current leakage paths. Second, and more important,
> accumulated dust can significantly reduce air circulation around and
> beneath chips, thereby reducing cooling, thereby increasing operating
> temperature, thereby increasing the liklihood of component failure.
[ed. note:I wish I hadn't lost the messsage quoted above. -- Mike Eve]
Oh, how true! My machine's keyboard began, over a period of time, to become
flaky - it'd transmit F when I pressed S, S for F, 4 for 2, 2 for 4, and so
on. The failures occurred more frequently when the weather was warm and
humid. I figured the encoder chip was bad and replaced it, with TEMPORARY
success. The new part began to do the same thing. I checked the power and
everything else I could think of, and finally in desperation applied a solvent
cleaner after blowing at the thing for a while with my lungs. The keyboard
STOPPED working altogether. I could see that it was covered with soaked-down
dust kittens and other gunk, and so my last great act of defiance was to take
a toothbrush to it, dislodging all that yecch, and lo and behold, I have a
working keyboard again, with a spare encoder chip for use when the one in use
DOES finally die. I don't recommend this course of action, but it is clear
that a) solvents can do more harm than good, and b) dust, etc., can cause
serious problems to an ordinary PC board.
Cheers,
Dick Binder (The Stainless Steel Rat)
UUCP: { decvax, allegra, ucbvax... }!decwrl!dec-rhea!dec-dosadi!binder
ARPA: binder%dosadi.DEC@decwrl.ARPA
==============================================================================
> From uw-beaver!tektronix!hplabs!ucbvax!mlsmith@nadc.arpa Thu Oct 4 01:58:24 1984
Denatured alcohol and Q-tips is a safe procedure.(Ethanol is also acceptable)
I do not recommend emersion as parts are likely not hermetically sealed.
If you must emerse, bake at 150 degrees F for at least 8 hours to dry.
good luck,
mlsmith@nadc.ARPA
==============================================================================
> From uw-beaver!tektronix!hplabs!hao!seismo!mcvax!sara70!gijs Wed Oct 3 07:59:26 1984
You can spray the board with freon. The best is to take all the chips
out of their sockets, clean their pins with an (ink) eraser, spray
sockets and pins with freon and put them back again. You can also
use this system on interface cards, but be carefull with gold
plated fingers. Use the eraser very gently on them or the gold will
disappear too. Freon should be sold in electronics parts or
computer supply shops. Good luck, Gijs Mos @ Free University Amsterdam
==============================================================================
> From uw-beaver!tektronix!hplabs!sdcrdcf!sdcsvax!akgua!uf-csv!leo Tue Oct 2 16:51:48 1984
This may sound a bit odd, but when I was in the military we cleaned boards
with plug-in chips & everything else in place in SOAP & WATER! Has little or
no effect on most things & works well, particularly if used in an ultrasonic
bath. You do have to let it dry thoroughly, though. No "close enough for
government work" attitiude will do.
=============================================================================
> From uw-beaver!tektronix!hplabs!sdcrdcf!sdcsvax!bmcg!mikel Wed Oct 3 07:59:20 1984
I use Isopropol Alcohol 75% is ok, but if you can find 90% that is better. Use
an old tooth brush and scrub. Alcohol is one of the best no distructive
cleaning agents that I've found. If someone spills anything on anything, get
out the alcohol. I have cleaned cranberry drink out of carpets and clothing.
Computers love it too. Try to use it outside, and avoid breathing the fumes.
The other agents used in the computer industry, but are harder to get are MEK
(Methel Ethel Keytone) and Freon (liquid).
Good Luck!
[Row, row, row your bits, gently down the stream...]
Mike Lesher
Burroughs ASG, San Diego, CA.
(..!bmcg!mikel)
===============================================================================
> From alcmist@ssc-vax Tue Oct 9 18:56:47 1984
I don't know where an individual can get it, but I have seen something
that would do the job nicely.
A repairman from Leasametric fixed a malfunctioning board on one
of my old group's HP terminals by spraying it with a freon cleaner.
I'm not talking about the quick-freeze stuff for chilling
components. This was slow-evaporating stuff that was liquid in a
plastic bottle under fairly low pressure.
He just hosed down the board with the freon. It took off the dust
like magic. It's chemically inert -- you can let it drip on the
carpet.
I'm sorry I can't remember any brand names or suppliers. The repairman
did say it was expensive.
Fred Wamsley alcmist
Oh yes...The repairman did claim that the freon he was using
stripped off oxidation. I am skeptical. -fred
==========================================================================
End of summary
About Hutto's Blue Dip: This tip came from some hardware types who
have used it to clean ICs to improve solderability. The ICs are removed
from the board, placed in a plastic tube with the Hutto cleaner, shaken
for a few minutes, and, presto!, clean pins. Supposed to remove tarnish.
I have been unable to locate Blue Dip locally, but here is the address if
any wish to pursue it:
The Harvey Co.
P.O. Box 66245
Houston, TX 77006
Normally, I don't believe in disclaimers, but, due to the nature of this
text, neither I nor my employer either endorse or warrant any of the above
procedures and/or products. You are entirely on your own!
--
Mike Eve Boeing Aerospace, Seattle
...uw-beaver!ssc-vax!ssc-bee!eve
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