Ferroresonant transformer supply repair

Lyle Bickley lbickley at bickleywest.com
Sun Sep 8 18:54:34 CDT 2019

Hi Kyle,

On Sun, 8 Sep 2019 18:42:06 -0500
Kyle Owen via cctalk <cctalk at classiccmp.org> wrote:

> Has anyone replaced the capacitor in a ferroresonant power supply with much
> success? My current understanding is that the capacitor and transformer are
> mated as a pair, so replacing just one of them would require careful
> consideration.
> The PDP-8/I I'm working on has a 704A in it, with a GE 8uF 660V capacitor.
> It measures a couple of nF on my capacitor meter, and I was told by the
> previous owner that it's dead.

We recently replaced the ferroresonant capacitor in a power supply on the CHM's
PDP-1. They do fail (thankfully, not often) - and they are not super-critical
as to value. If the one you're replacing has the same marked value, you should
be fine.

PDP-1 Restoration Team, CHM

73   NM6Y
Bickley Consulting West Inc.

"Black holes are where God is dividing by zero"

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