PDP 11 gear finally moved

Mark J. Blair nf6x at nf6x.net
Mon Jul 20 20:05:21 CDT 2015

> On Jul 20, 2015, at 18:02 , Tothwolf <tothwolf at concentric.net> wrote:
> I replace wax paper types with polyester (mylar), polystyrene or ceramic discs, depending on how they are used in the circuit (note however that for wound foil types, modern replacement parts do not mark the outside foil, which needs to be at ground potential in many tube circuits, otherwise the circuit can pick up noise and hum).

Funny that you mentioned that! I just watched a YouTube video today about how to experimentally determine which lead is connected to the outer foil for applications where that's important. Modern film caps may have a stripe on one end, but it doesn't appear to reliably indicate which lead goes to the outer foil.

Mark J. Blair, NF6X <nf6x at nf6x.net>

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