HP-21 Disassembly Help...

[Geoff Quickfall]

I will give that a try! Thanks Katie.

Been using the silicone for years, no problems (yet?).

Geoff

[PANAMATIK]

(04-17-2016 06:59 PM)PANAMATIK Wrote:  

(04-17-2016 05:31 PM)Geoff Quickfall Wrote:  Good fix Bernhard!

Do the centre keys have the same snap as the edge keys?

Geoff

The center keys are working perfectly! No touch and feel difference to the other keys.

Bernhard

This was a good question, which shows the knowledge of a real master restorer.

After a while I needed to add glue also to the center keys, because the ENTER key didn't keep the snap. But now it is stable since months. It is important to hold the two boards tight together until the glue is fixed.

Bernhard

[EdS2]

(12-03-2016 03:42 PM)PANAMATIK Wrote:  After a while I needed to add glue also to the center keys, because the ENTER key didn't keep the snap. But now it is stable since months. It is important to hold the two boards tight together until the glue is fixed.

Bernhard

Bernhard, many thanks for the photos and the update. Do I take it that 8 blobs of epoxy was not enough, and that you now used maybe 18 or 20 more blobs?

(I have an HP-25 which was disassembled before I got it, and I can't tell how many of the little plastic pillars would originally have had mushroom heads and be holding the keyboard together. Do all of them need reconstruction?)

[PANAMATIK]

(06-25-2020 07:25 AM)EdS2 Wrote:  Bernhard, many thanks for the photos and the update. Do I take it that 8 blobs of epoxy was not enough, and that you now used maybe 18 or 20 more blobs?

(I have an HP-25 which was disassembled before I got it, and I can't tell how many of the little plastic pillars would originally have had mushroom heads and be holding the keyboard together. Do all of them need reconstruction?)

Yes, as many heat stakes as possible should be fixed with epoxy, also in the middle part of the keyboard. If one or more are loose, when a button is pressed the keyboard PCB is not stable enough and deforms, this changes the click and feel of the inner buttons and makes them wobbly.


Bernhard