[Elecraft] Need some help on a K1 problem.

[Len [K4IWL]]

I'm hoping that there are still some K1 aficionados out there.
 
 
I ordered my K1 with the 4-band-filter board. I was not able to get the
4-band-filter to work so I ordered the 2-band-filter (since it's a simpler
board) so I could determine if it's a problem with the K1 main board or the
filter board. To make a long story short, the K1 with the 2-band-filter
works perfectly (40/20M) and the relay switching works. I then finished the
KAT and it works with the 2BFB just fine.
 
But here's the problem, I am still debugging the 4-band-filter inbetween
using the K1 with the 2BFB. When I plug in the 4BFB there is no relay
activity at all when I switch bands. The relays stay in the reset position.
I have run out of ideas. Here is what I've done:
Replaced the 4MHz resonator. Replaced the IOC with a spare that I have. So
far nothing works. I have visually inspected every solder joint. I have
reflowed the solder on all the IOC and resonator pads. I have checked
continuity between the IOC pins and the relays and they are all solid. I
have checked the common connection to all the relays for shorts and opens. I
have checked continuity through RFC1. There are no shorts that I have
detected or seen on the board (solder splashes, globs, etc.) although I'm
not ruling that out yet. Nothing I've done fixes it.
 
Any new ideas out there? Anybody else have this same or similar problem? The
relay switching has nothing to do with the RF paths, these appear OK when I
manually apply 1.5V to selected relays for the band configuration. RF is
getting through as it should on each of the 4 bands. Oh .. yeh ... I am not
getting any error codes on the display either. And when I switch the bands
with the front panel switch, the display changes but no relays activate.
 
72,
LEN, K4IWL
www.qrz.com/k4iwl
K2 #848,  K1 #1221,  Wilderness Radio Sierra (another Wayne rig),
Every RockMite imaginable, and a 15M HiMite.