[Premium-Rx] WTD - Racal RA6790/GM 40.455 filter for A3 second mixer board

[Nick England]

I'm trying to resurrect an RA6790/GM that I got out of the bin of parts
units at Fair Radio some years ago. I repaired the microprocessor board and
replaced the LCDs. (and still need to replace a bad membrane switch pad).
And find a 3kHz plug-in filter.

Actually I think I have everything working except for no gain through the
A3 board where there ought to be 60dB or so. I've got good input from the
1st mixer feeding the 40.455 MHz filter FL1 on the A3 board. But almost no
output from that filter - and the filter output pin measures 0 ohms to the
case. The rest of the A3 board looks OK with adequate 40MHz LO and
40.455MHz input from the first mixer.

The receiver barely "works" because there must be enough leakage to feed
the 2nd mixer stage - I can see 455 kHz output and hear signals but only if
they are -30dBm or so.
I guess I could use it for my nearby AM broadcast station but that's about
all...

So, does anyone have a parts unit with a filter or an extra A3 board?
I have cash or an A6A1 remote control interface board to trade.

Or can someone say - don't worry about 0 ohms because on some versions of
filter there's a coil across the output pin

I suppose I can torch open this soldered metal case filter and see what I
find. or haywire in a filter of some sort...

The parts list just says 08576. This Filter case says
08576
00136-164B75
Fc40.455Mhz Bw1db-20Khz

The working unit I have says the same except 00136-164Q75

Thanks in advance,
Nick England K4NYW
www.navy-radio.com