That suggests the open is between QB and SB2, perhaps including the make/break switch on SB2, depending on which side of the switch was included.

So it's in there somewhere.

ZB is the 1st Ball Relay, and should energize and trip when the game is powered on, then get reset during startup when the Control Bank resets, then energize and trip again when the first points are score.

But once tripped, it should not be energized and buzzing. A switch on ZB should open when ZB trips, to open the path to the ZB coil. So if it's staying energized after tripping, then that suggests that the switch either isn't opening or has some short to that switch.

My Target Alpha's 1st ball relay is not in the control bank, does stay engerized thruout the game after being tripped by the first points...

That's correct for Target Alpha.

But in this case, ZB is seen in the previous pictures posted of the Control Bank (which is where it's located on this era of game).

Nope.

If you can jumper from SB2 to QB and it works, then the open is in between somewhere.

Further, if you:
- jumper only QB and doesn't work; and
- jumper only SB2 and doesn't work,

then the open is in between them.

Given the proximity of them, the wiring should be able to be physically traced. You'll want to follow the path from the QB switch through to the SB2 switch very carefully.

But if jumping over them makes it work, then that's overcoming the open. Only the switch on QB and the make/break switch on SB2 need to be closed to complete that path, so it has to be right there somewhere.

Tilts are normally open, and the anti-cheat/bounce switches are normally closed. So there'll be the tilt bob, the ball roll, and then the one under the playfield for the three tilts.

then the one on the coin door, and the one on the bottom board that faces down both will be normally closed, but aren't tilt switches; those are the Anti-cheat and Bounce.

Does this wire run directly from SB2 to QB? (so it's like 3 inches long or such). Or are you saying it leaves the Control Bank and comes back before reaching from SB2 to QB? There's a branch off it that goes from SB2 into the tilt path (so tilt needs that SB2 switch to be closed in order for Tilt to work), but there should be a piece that goes from SB2 to QB directly.

So, if the game can't tilt, then that further points to that switch on SB2 not getting a good closed signal. See there on the schematic where the whole tilt path is after the closed switch on SB2? That's the same make/break switch that needs to feed QB. If you jumper there from SB2 to QB, then does Tilt start to work?

I can see in the picture where the connection at both SB2 and on QB has been messed with, so maybe that's possible. It would be helpful to have a picture of another Control Bank using this setup for comparison. But since this is a 'dot or' function, I would have expected that switch on SB2 to have had two wires on the one tab (twisted together), with one going off to the tilt path, and one going to QB. But I can't confirm that.

Since the under playfield tilt doesn't work though, that suggests the open is somewhere on the path to it and back to QB. There's going to be a Jones plug involved in that path too.

So you could try to chase that down, or leave the jumper in place (or add a bridge wire) to make progress on other aspects. But since there's only one of those wires on the under playfield tilt switch, it doesn't seem like there's going to be a return from there to QB either.

Would be curious to know if the under playfield tilt works with the jumper though.