Ultrasonic cleaning? Any experiences?

[Jim Creybohm]

Hi all.

I read a note posted by another reader on using an ultrasonic cleaner to clean his HP calcs. I am curious to know from others with more experience in this what kind of cleaning fluid they are using.

Are the calcs dismantled? I would think that cleaning some circuit boards might be OK, but certain mechanical things such as solder connections would or could break down? I can definitely see grime being taken off the keypad, for example thus perhaps eliminating the nasty wipe lines that you often see around the keys.

Are you using deionized water or something more exotic? I would think only water would be preferable?

And last, what calcs have you cleaned using this procedure?

[Frank Boehm (Germany)]

I purchased such a cleaner 15 years ago or so (when they were really expensive <g>) - the results were not too impressive. It's a nice thing for removing dust from small parts. A different story for 30 years old fat (fingerprints plus dirt) on plastics though - you can't use any aggressive solvents. The HPs are made of "good" plastics, still the prints might fade or the plastics might suffer when cleaned with the wrong stuff.
I'd suggest to disassemble the calculator; keys (2-shot-molds) are well suited for the cleaner, using some standard detergent. For the case, I'd suggest to use hot (warm) water with dishwashing detergent and a mostly-soft sponge. Don't clean the printed parts this way, only the plastic ("rough") parts...
For everything else, I'd suggest using window cleaner (without ammonia and without solvents) and q-tips. Be *very* careful, as you still could easily ruin the surface or printing. Better test this in advance.
It's usually not necessary to clean the electronics; window cleaner works well if desired. Be sure to dry the parts before using the calculator again.

So, if you can get your hands on a cheap cleaner - go for it, it might be useful. It's not suited for a whole calculator though - you nede to disassemble it....

[Thomas Radtke]

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Are the calcs dismantled? I would think that cleaning some circuit boards might be OK, but certain mechanical things such as solder connections would or could break down?

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Recently I cleaned a -45 purchased from a heavy smoker. I completely dismantled the machine and applied the german cleaner 'Sidol Küchenkraft' on all parts, including PCBs. It is not very agressive but as soon as you spray it on the parts, you see the tar running down with the cleaner. After that treatment, I applied lots of warm water (beware, if too hot, some plastic parts may deform!). There was still some dirt under the key contact arcs which I had to remove by hand (with a wooden toothpick thinned to less than 500 microns). I wonder how it could get there since the plastic sheet was still intact.

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Are you using deionized water or something more exotic? I would think only water would be preferable?

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This 'Sidol' works great, have used it for several calcs, including a TI-66 and a Casio. Unfortunately, no ingredients are given on the bottle:(.

About the ultrasonic bath, I have used them in the lab but never tried to clean something in them. If I got this right, Randy is using this method to not have to dismantle the calcs. In this case, no cleaner should be applied as it would be nearly impossible to get it out afterwards. At least, my 'Sidol' can be quite sticky if not washed away _very_ thoroughly.

Good luck,

Thomas

(Edited: You find a picture of that shiny 45 in the 'how to open 82001A battery pack' thread)

Edited: 22 Mar 2006, 7:30 a.m.

[David Smith]

When I have to use ultrasound on a machine, I use three cycles of distilled water, shaking as much as possible out between cycles. I have added some window cleaner in the first cycle and some Kodak PhotoFlo wetting agent in the last one. You can then dry the thing in a LOW oven or hot car.

I had a MINT HP-55 with a bad power switch and some flakey keys. I tossed the whole thing in the ultrasound since I did not want to mess with the rear label. It came out working perfectly. Also has worked wonders on HP42's that were dropped in mud and rivers.