So, I tried to get various local electronics guys involved in this to no avail. The guys that made the multiplexer threw shade at the concept of the multiplexer failing, but given the common-sense appeal of that as the culprit and the difficulty of getting anyone local interested in reviving this thing, I went ahead and ordered a new multiplexer to see if a couple hundred bucks and a quick swap-out would solve the communications problem. I'm going to try to make that swap this weekend and we'll see where that gets us.
Ultimately, I'm just trying to eke out a couple more seasons with this setup before upgrading, so now this thread is turning more towards what is the upgrade strategy to get from the system in the pics above, to a new system? So as you can see in the pics above, I currently have a "doghouse" up in the cockpit that houses an RCU-017 keyboard and some kind of display screen, and then a second dumb display down at the nav station, and an RPU-015 (that's the "black box"?) behind the nav station. So, here's what I'm imagining the process to be, but I'd love any thoughts on the accuracy (or wisdom) of setting off down this road:
1. Doghouse in cockpit: Demolish and sell display unit and keyboard on eBay.
2. Below: Uninstall RPU-15 and eBay.
3. Radar Mast: Remove radome (won't work with current gen systems - probably due for age-related failure)?
THEN
1. New TZT15F on bracket, after the old doghouse is removed (probably can't reuse that doghouse? Maybe a scanstrut pod?)
2. What happens below? Is there just a video out from the TZT15F that will mirror the output down to the old video monitor below? That would be easy? Adding a 2nd TZT would be expensive and difficult (different dimensions with existing screen)? Is there an equivalent of the RPU-015 needed? Doesn't seem so?
3. Presumably mount a new DRS4DL+ or similar?
Budgeting: Using notional Defender pricing and allowing for some cables / doodads and assuming it's a DIY project, about $7-8k?
Love any thoughts you guys have. Thanks!