Jeffrey,
I personally don't wash large capacitors. Maybe critical paper capacitors -
if they were used as the basis for an oscillator that had to have a tight
frequency range. Usually these capacitors are found in radios, and usually
there are means for readjustment.
I don't make a habit of washing big filter capacitors - I just replace
them. Usually they are found in heavy-duty power supplies and after twenty
years of use are ready for the trashcan. They get removed, the board goes
into the dishwasher with it's brothers, and a new capacitor gets installed.
My video games get the same treatment. For example - I have a Lunar Lander
that needs the 5v filter capacitor replaced. It was made in 1979, so it's
22 years old. When playing, and you give it full thrust, the rumbling
thrusting sound causes the 5v supply to drop to about 4.7 volts and you can
hear a distinct 60Hz power line "hum" in the speaker. The capacitor is shot
- it's a chronic problem in early Atari games.
I'd consider this when firing up an old computer and you get strange, silly
behavior. Put your voltmeter into "AC" mode, and check the AC voltage on
the various DC supplies. If you get 1/4 volt (250 millivolts) or more of AC
"ripple" on the DC supply, the power supply needs repair. Probably one of
those big filter "caps" needs to be replaced. Such an excessive ripple on
the DC supplies to the computer could very easily cause it to go wacko and
give erronious results, claim that 1 + 1 = 7, etc., etc.
The video game collecting guys sometimes will go bonkers troubleshooting
logic problems for days, before they realize that the filter capacitor on
one of the power supplies is shot and causing the game to act silly.
- Matt
At 02:53 AM 12/15/2001 -0600, you wrote:
>On Sat, 15 Dec 2001, Matthew Sell wrote:
>
> > I know that a good percentage of you are skeptical. Every one of my
> > games in my arcade collection had at least the CPU boardset in the
> > dishwasher. Several others had every single board through the wash.
> > All of them work, and did so before going into the dishwasher and
> > immediately after drying. Others had the monitors powerwashed. I took
> > an entire 11/780 out into my driveway and I powerwashed the chassis
> > AND backplane!
>
>I thought we weren't supposed to use the dishwasher on anything with
>capacitors.
>
>--
>Jeffrey S. Sharp
>jss_at_subatomix.com
Matthew Sell
Programmer
On Time Support, Inc.
www.ontimesupport.com
(281) 296-6066
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Received on Sat Dec 15 2001 - 12:12:59 GMT