My Pharaoh is acting weird. For those unfamiliar with Pharaoh, there are 6 drop targets on the upper playfield. Two banks of 3 drop targets.

My issue is that the game cannot recognize when all 6 drop targets are down, therefore the drops will not reset until after your ball drains. Each individual switch for the 6 drop targets work well both in test and game play. But after 3-4 drop targets have been knocked down, the game stops registering when the other drops are knocked down. All other switches in the game will still register when 3-4 drops are down, just not the other drop targets. It's like it can only handle the first few drop targets, then when you hit them all down it will not reset the drop targets until your ball drains making the game pointless. The same issue is true for the lower playfield drop targets.

I found a known working Driver board and swapped it in, and everything worked perfectly. Swapped back in this board and I am getting the same result as before. So I know that the issue is on the driver board. My question is what kind of issue does this sound like? bad transistor? pia chip? I'm not sure where to start.

I hope I explained this in a way that makes sense. I can shoot a quick video if that is helpful.

Very interesting thanks for the info. Any idea on how to tell if my board will need to be updated? Sounds like this could be the issue.

Man, thank you so much! That is definitely the issue.

From pinwiki:

"Williams removed some resistors from the switch matrix inputs and used wire jumpers instead. This happened from the start of System 7. The first thing to do with a driver board (which may not be from that game) is to measure these resistors and make sure you have the the driver board set up for the correct game. While you may be able to use a board with wire jumpers in System 4-6 games, using a board with resistors in a System 7 game will cause problems. Having the wire jumpers helps with switch sensitivity and helps with sensing more than one switch closed at the same time.
On driver boards from Black Knight and later System 7 games, there should be 8 wire jumpers (or zero ohm resistors) used on the switch matrix at positions W9-W16. These are located on the upper right hand corner of the Driver Board just to the left of J2, the top left connector which is the switch matrix column input. To the left are two columns of 7 resistors, the second column should be the wire jumpers, and also the top position of the next column (column with 2 resistors only).
On System 4-6 Driver boards, (games like Alien Poker, Firepower and earlier SS games) there are usually 330 ohm resistors (orange, orange, brown) in the same 8 locations. For Black Knight and later (System 7 games) they are called R204-R211, and are zero ohm resistors (usually a tan body with one black stripe). You can replace or jumper over them with wire leaving the resistors in place. In all other aspects the driver boards are identical, so it's easy to convert between the two. This is why they are usually known as System 3-7 driver boards."

What my board looks like:
IMG_3854 (resized).JPG

What my board should look like (pic of the working board I used):
IMG_3855 (resized).JPG

Any tips on how to go about "fixing" this?

Pinwiki says:

"You can replace or jumper over them with wire leaving the resistors in place."

So it doesn't sound like I would have to remove the resistors, just add the wire. What type of wire should I use for this?

Fixed!

Thanks everyone! I used legs off of some diodes and left the resistors on. Works great now!