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HP-25 Keyboard fix, dissambely advice ?
08-12-2018, 06:02 PM
Post: #1
HP-25 Keyboard fix, dissambely advice ?
Hi All
I have inhereted my fathers old HP-25 and the battery pack seems to have leaked and effected the keyboard. Got the case apart, but need to remove the board with the buttons from the front cover. Any advice on how to do this ? Does not seem to be an obvious method.
While were at it, seems like the battery door is stuck, and advice on this as well ?
Many Thanks
Allstonma
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08-14-2018, 08:51 PM
Post: #2
RE: HP-25 Keyboard fix, dissambely advice ?
The keyboard is heat-staked together and is not designed to be disassembled, unfortunately.

If it's just a few keys not working, though, this post may be of some help.
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08-16-2018, 07:07 AM
Post: #3
RE: HP-25 Keyboard fix, dissambely advice ?
Allstonma,

It is not easy but the keyboard should be fixable - I fixed a completely corroded keyboard a few months ago

The first step is to cut off all the little black bubbles (post tops that stick out of the keyboard back) with a razor blade
That allows you to disassemble the keyboard. You can then clean up the keyboard corrosion with vinegar (for example). You probably need to scrape off corrosion from under the ‘cricket mechanism’ (bent metal tabs that click to register the keys) - I used a thin enameled wire for that

After the cleanup, you should check that the keys register using an ohm meter
You also may want to cleanup the off/on and prgm/run sliders as well and add silicon grease to smoothen the sliding mechanism

To seal the keyboard back, make sure you clamp the front and back parts tight and drop ABS glue with a syringe on top of each post to replace the original black bubbles you cut off (I used successfully Oates medium black abs cement which I bought at a hardware store)

If the rest of the machine is completely corroded and does not work, you can get a Woodstock LP kit from Panamatik which will give it a new life

Good Luck!
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