Quoted from Playdium:The previous owner had connectors 121 and 125 reversed. All set now with the lamp circuit for the backbox.
This is most likely caused by not having the correctly sized housing. It is not a must but rather should (very strongly advised) to have the correctly sized housing as well as being keyed (the key pin is blocked). If the housing is correctly sized with the key pin installed, it is VERY hard to make this error. J121 is 11 pins. J125 is 9 pins.
Looks like the previous owner used an 11 pin housing for what should be a 9 pin housing for J125. I don't see a key in pin 4. This happens to be exactly the same as J121 (11 pins keyed at 4). It is very easy to install the 11 pin housing into an 11 pin header, especially when the key pins align. This is why it is strongly advised to use the correctly sized housing. Hint: you can cut it down to size if need be.
Quoted from Playdium:I found the red/wh going to J106-5 and the blue/blk going to J125-7.
The problem here is, the pins at both of these locations have 22vdc. That's the pin on the board.
The J126-6 location has a blue/blk attached that runs to the playfield harness.
So how should these be connected and what voltage should I see?
This is correct. The voltage (supply) for the "Backbox Clowd (sic)" (backbox) comes from J106-5. The drive for this is at J125-7. The voltage (supply) for "The Power" (playfield) comes from J107-5,6. The drive for this is at J126-6.
There is voltage present at all solenoids (flashers) at all times (assuming a coin door interlock switch is closed if present). The software controls the path to ground through the drive transistor (2N5401 and TIP102 and/or TIP36C).