Bill Garber wrote:

>"John" <twohandsfree@hotmail.com> wrote in message
>news:e639cb5b.0312161712.75cd35c2@posting.google.com...
>: FWIW .....
>:
>:   For my ZipGS I made it's CPU cable out of an old IDE HD cable
>and a
>: 40 pin insulation dipslacement connector from Jameco - nothing
>: special, or maybe I was lucky.
>:   Of course a Zip is not a Transwarp, but I haven't had any Zip
>: related problems on this ROM 03 for years. (I try not to remove
>or
>: touch that cable.)
>
>Thanks, I'll look up that connector. I think
>the problem is that I have to reverse the pins
>in the 40 pin IDE connector that comes from the
>card itself. They may be getting damaged when I
>press the cable back in. Probably should get new
>ones. Once the wire is pressed between the forks
>they can spread open and not make contact

I've always had good luck using a vise to clamp the "top" onto
the connector while it is seated in a disposable 40-pin socket.
I stop compressing _just after_ the top has made good contact
with the body of the connector.

The socket protects the pins and allows the right amount of
force to uniformly seat the cable wires in their "forks".

I have never had a problem with IDC connectors that were
properly seated, even if manhandled.  The problem arises
if the wires were _not_ fully seated.

The design of the IDC "fork" is such that it first cuts the
insulation of the wire, then abrades the wire(s), removing
any oxidation, and in the process brings the edges of the
"fork" into very intimate contact with the newly exposed
fresh metal (of both the wires and the fork).  The resulting
metal-to-metal junction, under pressure from elastic forces,
is hermetic, and will not be subject to oxidation.

If the connector is under-compressed, the connection will
not have enough pressure to withstand inevitable movement.
If it is over-compressed, or improperly aligned during compression,
the "forks" will be overstressed, and they will not be able to 
maintain sufficient pressure to maintain hermeticity.

There are, of course, special tools to compress IDC connectors,
with dies for each connector type, but they are a bit pricey for
occasional use.  ;-)

-michael

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