> analogue switches in packs of 50...
I have 4 spares for 2 CMI keyboards which I've not used yet. Just lucky I guess.
> 'Orrible crappy things that they are.
Agreed, and fairly noisy, too by modern standards. I think maybe part of their general longevity in the CMI keyboard context is that it's a bit of a sheltered workshop for them in there. They only ever see signals well inside their operating spec, are gated very gently, and they sit on a big piece of cool circuit board attached to an even bigger piece of metal, that doesn't get very hot, unlike the system enclosure. The CMI use case is unlike some 4051 uses which come direct from outside world plugs, or nearly so, which I'm sure you've seen in HAM circles. And of course CMOS is way sensitive to ESD, which I think is probably the main degradation/faiure culprit for most old chips that have survived normal use for more than a few hours of burn-in, and the keyboard 4051s never see any static unless you play your CMI in a Van de Graaf room or a lightning storm, like the famous photo. :-D
Joe
On Sat, Mar 5, 2011 at 2:50 AM, Gordon JC Pearce <gordon@gjcp.net> wrote:
On Sat, 2011-03-05 at 02:29 +1100, Joe Sleator wrote:That said, I don't do many synth repairs really but I still buy 4051/2/3
> Personally I've seen connections and springs fall off and get filthy
> way more that I've ever seen 4051s blow up from normal use.
analogue switches in packs of 50...
'Orrible crappy things that they are.
Gordon MM0YEQ