[R-390] Drop-in, GFCI-friendly line filters for R-390A's?

[Tim Shoppa]

Roy wrote:

> The line filters normally do not "leak".

I'm not sure exactly what the filter terminology is when they
specify leakage current, but getting to the filter topology

>  The capacitors in side there pass 
> ac current because of the basic nature of capacitors. There
> happen to be a lot of capacitance [...]
> Each of these capacitors has the value listed as "Part of
> FL101, listed for reference only."  One email some time
> ago indicates that they are 0.068 uF paper caps.  Thus, the
> capacitance from the hot line to chassis is 0.136 
> uF.  Let's refer to an capacitance calculator at:
> http://www.opamplabs.com/rfc.htm
> and get a "resistance" of about 19.5 kilohms.

Well, AC impedance.

> Then the calculator at:
> http://www.opamplabs.com/eirp.htm
> gives some six miliamperes of ac current.
> This is above the four milliamperes of the ground fault
> interrupter above.

Yeah, my experience is that the R-390A stock line filter will trip a GFCI
even when the unit isn't powered on.

The Y2K manual and past posts on this subject have
some confusing verbiage ("If the radio continually
trips the GFCI check the line filter") that seem to say that only a "bad"
line filter will trip a GFCI.  But my experience is in agreement
with what you write, Roy, in that a "good" stock R-390A line
filter will allow enough AC current through that it will trip a
functioning GFCI.

It would seem to me that the ladder logic should be that if your
R-390A has the stock filter and doesn't trip a GFCI, that either
the stock filter is bad or your GFCI has failed shorted.

We're about a half decade too late to update the Y2K manual,
right?  Who's the current maintainer?

Tim.