I'm a WPC and later guy, tinkering with a system 7 game. Any of you experts can help?

I have the right slingshot locking on. It does NOT lock on when the game is turned on so that rules out the transistors. As soon as the start button is pressed, it locks on and remains on until I turn the game back off.

I played 2 games and during the 3rd game is when it started - everything was dead [blew a fuse].

I tried swapping the socketed 6821 up near that section of the board and I had a 7402 and a 7408 socketed and tried those, too to no avail.

I do have a logic probe. What are the test points to attach to on the MPU? +5v and GND?
THere's still another 7408 and 7402 chip in that area soldered in, but don't really wanna just replace stuff till it's fixed.

Any thoughts would be awesome. I miss my slingshot!!

Oh - I will say that the slingshot switches are NOT touching and the EOS [is that was they are called?] on the slingshot appears to open when the plunger goes down.

Thanks for the help guys. I used barakandl's method and found one leg bad on the topmost 7408.
Took it out, socketed it, and put a new 7408 in there and it's working again.
THanks guys and thanks for the tip Jeff - I'll jot that down for future reference, too!

Back to Warlok!

**On a side note, apparently you can't rely on the orientation of the other chips on the board when inserting them and need to pay close attention to the way they came off. I turned a 7408 into a 7409 and blew the other one and a fuse. LOL. Newb's, huh?

And ROb Anthony's IC tester came in awesomely handy to test those chips to make sure the socketed ones were good and the one's I was putting in were good.