On Fri, 8 Mar 2002 at 22:52:34, Dave wrote:
(ref: <[EMAIL PROTECTED]>)
>
>
>On Fri, 8 Mar 2002, Tony Firshman wrote:
>
>> 1) Keybounce. They produced a replacement 8749 to 'cure' this, which it
>> did. Unfortunately it killed ser2 (8-(# Hermes/superHermes have cured
>> key bounce with all keyboards using the pcb connectors.
Any comments on bounce? Mind you I wouldn't mind at all if users had to
buy Hermes (8-)#
>
>> 2) The pcb was sub-standard, and the 'gold' plated contacts weren't.
>> After maybe 5 years, all the contacts need cleaning - quite a major
>> dis/re-assembly job
>
>There's a lot of incentive to have poor or false gold contacts - having a
>large PCB like that plated will more than triple the cost of the PCB. I'm
>looking for a way to do quality 24K gold plating in-house - it looks like
>it will cost a few hundred dollars to buy the equipment, and a couple of
>days practice and training to learn how to use the equipment properly.
That sounds very good. There really is no substitute for 24K gold, but
yes, it is expensive. It added about 40p to the cost of RomDisq pcbs.
>
>> 3) The ribbon cable was soldered each end, and fractured very easily
>
>My design will not have soldered ribbons. It will have IDC cable and
>connectors, for simple re-usability.
That is perfect - that means the kbd can be removed, presumably, without
removing the ribbon cable.
>
>> 4) The thin pcbs weren't thin enough and ruined the connectors for std
>> membranes
>
>The trick to this was to stick a couple of layers of tape to the back of
>the ribbons to make them thicker.
Yes indeed - have done that myself. It makes for a good tough end of
tails too. I in fact routinely add one layer of tape when fitting
membranes to QLs (when I remember)
> However, my design will have thin pins
>which enter the two sockets.
Flattened pins? If not, then the contact area might be
small.
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