So in switch test mode you aren't getting any hit on the upper flipper when you press the button.

Check the connection to the fliptronic II board, maybe? Page 3-15 of the manual has a basic wiring diagram for the flipper button opto boards...

What do you mean by "upper board"?

Check the wires going into J905 on the fliptronic board. Make sure they are all plugged in well to the molex connector and reseat the connection too. Capture (resized).PNG

check the opto voltage at the fliptronic board connector and interrupt the flipper button opto.

Okay, so the opto switching is getting TO the fliptronic board. Did you check the fuses with a multimeter for continuity?

It's been a while since I've worked on The Shadow so I don't remember how the optos are routed for the switch test. It's strange that it gets to the fliptronic board, but doesn't show up on the switch test.

Pretty sure if the opto signal makes it to the fliptronics, that's where the solenoid power/switching happens. I don't think it goes to the CPU board first. But the opto not showing up in the test while it DOES show up at the fliptronics board is puzzling. If you haven't solved it I'll try to get a look at the schematics this weekend.

Okay, so page 3-13 of the manual has the general wiring flow for the flippers. They DO go from the opto to the Fliptronics and then to the flipper power and through to the CPU board (where the switch test would show it). So I'm thinking your problem is on the Fliptronics II board since it's not flipping the flipper and it's not passing through the Opto status. J902 is Flipper power/hold pairs, and J907 is the 50v for the flippers.

Looks CAREFULLY at J903 on the fliptronics board. This is the cable that connects to the CPU board. Remove and replace it a few times, making sure you have it on just right and aren't shifted a row of pins. Then try the switch test again. The flipper button optos should be showing up on the far right of the screen in that test and change when you press the buttons.

If that doesn't work, looking at the Fliptronics schematic, it seems most likely that the U5 chip (74HCT244) may be bad or flaky since the flipper input passes through this. With everything else you've tried, this seems like the most-likely failure point. If you replace it, have it SOCKETED so replacement at some point in the future is much easier.

There are two parts to your problem and you need to distinguish them to figure out where to look.

Flipper button switch (opto board) recognition.
Flipper power.

Test the flipper power side by running the flipper test (T.12) in the tests available. Make sure you have high voltage available by closing the interlock switch in the coin door. If the flippers pass the power test then there's nothing wrong on the power side of your issue (and nothing wrong with the fuses or transistors on the Fliptronic II board).

Test the flipper button switches (opto board) by running the switch test (T.1) and pressing the buttons. I think you've already done this and the upper flipper buttons do NOT register. These are F2, F4, F6 and F8. It also looks like you've verified the voltages for the optos and the optos appear to drop to 0V when interrupted.

To differentiate between the optos and the Fliptronic II board short the pins on the board at J905. Enter switch test (T.1).

F2 - short pin 1 to pin 6.
F4 - short pin 2 to pin 6.
F6 - short pin 3 to pin 6.
F8 - short pin 5 to pin 6.

If shorting the pins does not register the switches then your problem is on the Fliptronic II board. It could be the LM339 or the 74HCT244 or both of them. The LM339 in question is U6 (connects to J905) and the 74HCT244 is U5. You can statically test these in circuit to see if there is a pin that is shorted or open.

I've had this problem on a Fliptronic II board twice before. Once was both the 74HCT244 and LM339. The other time it was the 74HCT244.

I agree with Vireland. If you replace the ICs put a socket in the board first.

I think since the buttons are not registering at all in the switch test, and the optos work (voltages drop when interrupted) flipper power isn't even on the menu for this point in the repair. I'd concentrate on getting the switches to actually register first. It could be the LM339, but the 74HCT244 is more likely, so I'd do that one first, and if it's still not working, then the LM339.

Im the person who bought his Shadow. Just thought I would update the thread in case anyone in the future finds it.

I replaced the 74HCT244 first, and it still wasnt working. I replaced both LM339's (wasnt sure which one and they both had been replaced at some point with generic chips). After that, it worked great!

Thanks for the info

Thanks for the followup post to resolve the issue!