I fix these machines so if you ever come across one and need it worked on... and it's "complete" let me know and we'll get her up and running! I work on all of that old "rare" random EM stuff in the Chicago area. Shuffle targettes, shuffle alleys, ball bowlers, EM pinball machines, rocket shuffles, shooting gallery gun games, rifle gun games, bingo machines..... you name it I can probably fix it!
The shuffle targettes are a ton of fun to play when they are up and running! If you like Skeeball or shuffle alleys it's right up your alley. I know a local guy that has 2 of them for sale. If you are interested I can get you in touch with him.
And as Hoopjohn stated, these machines almost always need to be completely gone through. Under the play field are a couple stepper units, a relay bank, a couple other short rows of relays, the score motor and the puck return lane. If you look at one of these machines OPEN IT UP BEFORE YOU BUY IT. I've found the puck return motors to be missing as a common issue. There is also a drive belt that is frayed or missing most of the time. It is a Gates Truflex 0160 belt. They are still made and readily available as they are used in many small engine applications as well. Make sure you put a 4 amp fuse on the wiring to the motor if it's missing too.
Some of the puck return lanes have a switch towards the front of the lane before the puck pops out to stop the motor as the puck shoots back out to the player and some of them are shut off by the score motor on it's normal game rotation between shots. Once you hit a hole, the puck return motor starts running until either of those options are connected to stop it.
There are generally 2-4 stepper units in the back box, along with a reset relay that goes to each score reel. I've found that player 1 and 4, 2 and 5, and 3 and 6 are together.
The score reels are almost always seized up on these machines too. You'll need to go through all 18 of them and take them apart to get at the small lever on the spring. It's all jammed up from the old lube/grease used on them. Clean all parts and contacts and reassemble and the score reels will work like brand new. These can take a TON of time to do properly since there are so many of them, so you can manually set them all to zero and just clean player 1's score reels to see how your functionality on the game is going in a one player game before you spend a ton of time cleaning them all at once. It' gets boring trust me.