restoring a Pulsar Y739 keyboard

[albertofenini]

ciao a tutti, (hello everyone)
I'm trying to restore apulsar Y739.
The module is working fine and keyboards contacts do work as well.
The problem with these watches is that (differently from seiko's)
the rubber of the keyboard usually get rubbish and break apart.
Does anyone have ever tried to replace it with something different ?
I was thinking about using a micro spring for every keyboard contact or a a different rubber layer.
Any idea or suggestion is very much appreciated.
Thanks for help, Alberto


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[Kasper]

hi Alberto,

can you also post a shot of the other side of the watch and the module so i can have a look?

[albertofenini]

I sure will, I have several watches of this type.
These were manufactured by both Pulsar and Alba.
In some of them I have the keyboard completed removed
so that it can be seen how the micro buttons work.
I'll do it after the weekend, take care Alberto

[albertofenini]

Another idea I had, but never tried to, was to use molded silicone,
like that one used by the dentist to make an imprint of a tooth.
I believe that it could be used to create a rubber layer that could
replace the original one.
Anyone has tried ?
take care Alberto

[retroleds]

Alberto:
The rubber pieces CONDUCT electricity(fine metal powder in the rubber). So regular silicone won't work. Those are quite a dissapointment - I personally shy away from them. If it was as simple as having something press a switch, you could use any number of materials. Alas, it is not so.

Idea: Go to store that sells cheap, made in China products and find a calculator watch. Buy it and go outside and tear it open. If the rubber used for the contacts is the right size, you are in luck. The only other realy usable part I have found was the contacts from a large "mystery hands" LCD watch(llooks like an analogue), which had a round matrix of contacts, one for each minute/second point. No, I cannot give up the few I have.

[albertofenini]

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[albertofenini]

Dear All, I have uploaded all the possible interesting pics.
There is the module, the lcd holder, the keyboard (front and back),
the buttons.
The most interesting thing, is that the rubber DOES NOT need to conduct
It's true, it does in most of this type of watches, but not in this case.
Looking at the pictures, you will see that the keyboards contacts on the module are closed by pressing the yellow layer thru the keyboard holes.

As a matter of fact, I was able to get the watch in calculator mode, press two digits (8) with a toothpick, which is definetely not conductive.

This said, I can think of a couple of options :

Option number 1 : micro springs. these will be placed under every button and kept in place from the white plastic shield, and will also have the effect of keeping the buttons well "up".

Option number 2 : molding a replace part with some silicone and then have it underneath the keyboard like the original one. In this case I'm afraid that the silicone will be too soft and will not apply the right pressure to the keyobard layer.

Also, I need to figure out how to replace the gasket that keeps in place
the faceplate of the keyboard. I suspect that originally is was all in one
with the rubber layer.

What do you says ?

There are often a number of these pieces on the "auction site" at cheap prices, exactly because of the keyboard failure, so I thought that the study of a replacement may be of interest for few of us.

Thanks in advance for any help, tip or advice.
take care Alberto