DaveC wrote in
:

Relay-logic controlled printing machine, 110 vac.

A 300mfd (150v) electrolytic cap is used together with 25K (25 W) ohm
wirewound pot and a 5K ohm relay coil to control a variable time delay
before the relay opens.

The cap is shot (measures less than 1mfd). I'm having a hard time
finding a replacement locally. (Yeah, I know: Digi-Key, et al) But I
need to get this up and running today.

What other common types can I use in place of this can-type cap? (It has
2 wings that rivet to the sides of the opening in the chassis and solder
terms make the connection below the chassis.) Maybe poly-somethings, two
in series or parallel?

It's a Mallory FP119A.

Can I use a non-polar electro? (The wiring diagram shows a polarity
indicator.)

Or a motor-start cap? ::

http://tinyurl.com/y9d3ks6


A motor start cap should be ok. They're meant for intermittent use under
heavy load so they don't accept heavy ripple currents for lomg, but this one
won't have to, with a few tens of kilohms between it and the mains.