cleaning the boards

[Steve Harrison]

At 11:32 AM 1999-12-15 -0800, Ed Kotkiewicz wrote:
>kevin smith wrote:
>
>> does anybody know whats good to clean the circuit boards without hurting
>> the components on it. i got one that's real dirty and to tight to get at
>> by hand.
>
>EK> What George and Steve have stated is good info.

TNX; but...

>I would also recommend keeping those old toothbrushes around for those
scrubing jobs.

NEGATORY!!! Don't take the chance of having a toothbrush dissolve in the
alcohol, and ESPECIALLY any flux cleaner, most of which used to be far
stronger than alcohol. Yes, some plastics resist the alcohol; but some
simply soften first and then gradually dissolve. I wouldn't chance it.
Obviously, toothbrushes work great when not used with solvents.

Also, DON'T be rough with the brush when it comes to cleaning components
with painted or stamped labels; the labels often will dissolve, with the
ink running all over the component. Heathkit crystal filters, in
particular, do this.

>I wouldn't be too concerned about the aftereffect of
>that slight clouding that you see after using alcohol.

I wasn't concerned about any OPERATIONAL effect, as much as the fact that
the white residue, whatever its cause or composition, was really, REALLY
unsightly. When it happened on prototype boards in the labs, we couldn't
show them to the customers, who might think we weren't using decent-quality
parts or something. Here, we're talking mostly about restoring older,
becoming-scarce equipment where one of the reasons we're doing all the
extra work is to clean them up to restore the older, pleasing appearance.
So I'd be EVEN MORE concerned than with newer, none-boatanchor stuffs.

Bottom line, especially on the older equipment: DON'T USE A SOLVENT unless
you absolutely have to; and restrict the application to the immediate area
where it's necessary, if at all possible. In other words, don't just pour
alky over the radio then start scrubbing.

>When making your final cleaning step, blow some air over the board.

I've got a high-velocity muffin fan hanging on the test equipment rack for
cooling soldered coax connectors and alky-washed stuffs like that. Also
comes in handy when I let the smoke outta something inadvertently :o)))))))

And remember the fire danger of using alcohol, too: don't smoke while
you're using it. If the fumes are heavy enough on your workbench, you can
even cause a flash fire should you do something that causes a spark, such
as hooking up a power supply to something or other, or even plugging in
your soldering iron, while waiting for the alky to evaporate. I saw a young
tech one day about 20 years ago forget about this while using spray flux
cleaner; he happened to spray the stuff toward his ashtray on the
workbench: POOF!!! Set off the fire alarms (but not the sprinklers) ;o))))

Use Situational Awareness, in other words.

73, Steve K0XP

Sponsored by the City of Tempe 

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