after a bath, a Pioneer clicks no more

[vaklaff]

Hello

I got hold of a 32s that apparently suffered a beverage spill over the keyboard and then spent quite some time stored without usage. I gave it an overnight bath in distilled water, then rinsed it a few time with distilled water and IPA, baked it on an oven and then just let it lay on my desk for a couple of days, five maybe.

To my delight it works, it passes all the tests including the keyboard one. There's one wrinkle though. The keys work reliably and uniform, unfortunately they don't click, their action feels mushy. It's not a principal problem for me, I don't plan to use the calculator regularly, just for fun programming now and then. Nevertheless if there's an easy trick to restore the clicky feel then I'd like to try it.

Any experience, suggestions? Thanks in advance!
v.

[SammysHP]

The click comes from the domes embossed in one layer of the membrane, right? Maybe there's still some liquid between the layers?

[vaklaff]

(08-26-2022 07:57 AM)SammysHP Wrote:  The click comes from the domes embossed in one layer of the membrane, right? Maybe there's still some liquid between the layers?

Thanks, let's do some more baking then!

[franz.b]

if it helps, I have restored an HP-27s that had been flooded with water and then abandoned. I completely disassembled the keyboard and replaced the plastic rivets with micro screws. I cleaned all the various layers of film that make up the keyboard and restored the damaged tracks with a conductive marker. It worked well. You can find details here.

[vaklaff]

(08-26-2022 10:31 AM)franz.b Wrote:  if it helps, I have restored an HP-27s that had been flooded with water and then abandoned. I completely disassembled the keyboard and replaced the plastic rivets with micro screws. I cleaned all the various layers of film that make up the keyboard and restored the damaged tracks with a conductive marker. It worked well. I guess the 48 has the same construction philosophy. You can find details here.

What a thorough work, thanks for documenting it! I don't plan anything of such complexity, at least not at the moment and this calculator. If anything bad happens to my main Pioneer, your restoration record will be invaluable! Once again thanks for it, I love when people do and write such things, IMHO it's the best part of this forum.

On a related note, I "plan" to repair of a 28s. I suspect the only thing bad there is the pressing foam, making not enough pressure. With all those hard-to-remove labels and rivets it's a job for someone as skillful and resourceful as you are, not for my butter fingers. Currently I'm at phase 1, plucking up courage; this phase has already been taking several months :-)

[vaklaff]

(08-26-2022 08:43 AM)vaklaff Wrote:  

(08-26-2022 07:57 AM)SammysHP Wrote:  The click comes from the domes embossed in one layer of the membrane, right? Maybe there's still some liquid between the layers?

Thanks, let's do some more baking then!

The diagnosis was spot on, each baking session makes the keyboard action a bit better.
v.

[johnb]

(08-27-2022 12:32 PM)vaklaff Wrote:  

(08-26-2022 08:43 AM)vaklaff Wrote:  Thanks, let's do some more baking then!

The diagnosis was spot on, each baking session makes the keyboard action a bit better.
v.

A few years ago, I bought a nice-looking HP 32sII that was being sold for $10 as "broken" because someone had spilled an entire can of cola in it and just let it sit for months!

It took an entire Saturday of repeatedly performing the following cycle:

* 20 mins face down in ultrasonic bath of lukewarm distilled water
* gently shake out gunky water
* bake 2 hours in 150°F oven
* gently tap for maybe 10 minutes while astonishing amounts of brown powder came out
* clean the ultrasonic, replace with fresh water, and repeat again!

That slight mechanical agitation was key to getting all the gunk out.
I didn't stop until I could just tap-tap-tap and get NOTHING out.
I followed with one more baking session and let it sit overnight.

Here it is years later, it still works great, and is in my "daily driver" rotation.