On Sat, 9 Mar 2002 at 20:19:17, Al Feng wrote:
(ref: <[EMAIL PROTECTED]>)
>BTW. Just as many want to hold to their notion that the material
>selection, alone, is the problem, I will maintain my belief that if the
>tails were not located in proximity of the heatsink that the problem of
>premature aging would probably not have occurred.
I don't think so. I have seen brittle membranes in QLs that have been
very little used (according to their owners). Heat would certainly
accelerate the aging, but oxygen and evaporation are also factors.
>
>BTW2. The fact that the chimney effect draws smoke out the vents behind
>the heatsink MEANS that is the hottest location inside the case. The
>fact that a peripheral is usually plugged into the expansion slot means
>that the optimal air flow that might cool the tails just doesn't occur.
>Think about it.
>
>As noted by almost EVERYONE, the failure IS, indeed, usually at the bend
>in the membrane tails which is adjacent to the heatsink when the upper
>half of the case with the keyboard is in place above the motherboard on
>MY QLs rather than being at the "opposite (?) end" as you seem to
>suggest!
That is _only_ because of the sharp bend. The material is just as
brittle at the pcb end, but not under stress. The tail is equally
brittle along its whole length in my experience. Often when removing
the old membrane, a sliver is left in the socket.
It the manufacturers had installed with a gentle curve, then I don't
think we would have seen any membrane failures on unopened QLs.
.... and I have repaired a lot of keybosrds (8-)#
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