ADM3A keys sticking

[johnx993]

On the keyboard... other than spills, the keys can stick because the white square plastic tube the key peg sits in gets cracked over time.
I've tried super-glue, epoxy, and MEK from plastic model building. Nothing seems to work.
But it may not be working as I use small amounts of glue - for fear of freezing the movement.
Next, I'm considering using a fine point hot iron and melt the inner edges of the square tube. (as it always cracks on the edge).
Anyone have any experience with this? Or am I headed in the completely wrong direction?
-J

 

[ldkraemer]

If you have some Dental Floss or Dial Cord, you can wrap it around the Plunger, then use a bit of
UV Glue to put in the cracked edges, Cure with UV light and see how it goes. This is about the
ONLY way to hold the Plunger together and allow the keycap to stay in place. You can remove the
Floss or Cord after the UV Glue is hardened.


Larry

 

[RolexTM]

Had the same problem. After cleaning still some keys stuck. What worked is, bend the upper edges of the outer plastic cage a bit outwards with a small plier.

 

[johnx993]

All good and logical suggestions.
Sadly, none of them worked in my case.
I think my cracks are just too long.

What did work for me was to remove the plunger keeping the key still attached then use a fine tip soldering iron at 450 deg F to gently scrape up little mounds of plastic to fill the crack and reinforce the area. Then run the side of the soldering iron over the area to make it smooth. Then sand the exterior of the plunger sides as needed to ensure they are square. And finally apply a little silicone grease to the plunger sides to ensure smooth operation.
Very tedious work and care is required to take up just enough plastic and not melt a hole in the plunger and also, of course, to be careful not to mar the keytop!
I found keeping the key attached allows you to form the plastic in the stressed position. Performing this procedure without the key means stress is applied to the crack area again once the key is inserted - and in some cases caused the crack to re-appear. Leaving the key attached will form the plastic with enough stress to hold the key but not enough to cause a crack.
-j