Wow...well theres your problem.
Well not really,
Assuming components functioned, need to be interconnected? Odd. Obviously I think someone has fudged stuff for some reason. I seriously doubt this factory, wouldnt have mixed mfg parts, but it looks like all A-Tek.
But If the antennas coax doesn't go to plate then head not being amplified nor is signal being sent to plate (assuming your tv hooked to plate)-basically no antenna. Odd. Could be there still is something broke and it was disconnected by previous owner.
Yes the Winegard and Antenna Tek are VERY similar. IF the head fits your arms yes the inside wall plate will power (if it works), it just sends power to head. What I dont know even though they look identical if they indeed are physically interchangeable. Problem is if head doesnt fit, then what. If the wall plate isnt sending power? $25(it could be powering indicator light but not to coax). Also you still need gears, $15.
Getting close to complete Winegard RVW-395 kit-(new head w/wingman, arms, mount, inside amplifier plate, coax) everything but roll of byutl tape and some caulk for
$108 free ship
Amazon-
$89+ship
@AdventureRv.netjust sayin.
As to wiring the plate there are plates with different functions, dont know if labeled. Some run differnt number of TVs, inputs (over the aire or cable). 3 posts, 1 to ant, center for cable input, one to second tv.
The comment about coax ending at roof inside cabinet- from the anttnea or the tv side? Might have had a short jumper coax to plate.
Im also unclear-when hooked up before, TV was direct to anttena or plate?
No signal if direct wired would make the head board suspect-however it could also be signal non-amplified just too weak or pointed in right direction on intial setup. Though easy to spend your money and recommend replacing it all, I think I would backtrack and see what really isnt working as it wasnt hooked up.
1st Have you tested the output of plate to antenna, attach a short piece of coax to ant post of plate, test center lead for power. If you have power then it would drive a new head.
Coax cable is always suspect. test (disconnected no power)continuity between center and ground, shouldnt be any, test continuity between ends of coax center leads, then ground. (or replace)
If plate and coax good I would set the head back up retest (tv to plate, plate to ant). If nothing try reorient 90° retest.