Pull the row and column connectors off the board and run a simulated test of each switch. Use a jumper wire to connect between pins on the board. It might be a problem on the board and not on the playfield. If everything works right with the playfield switch wiring disconnected, you can at least rule the board out.

Jim from Rottendog was very helpful to me just recently in diagnosing and fixing a sort of similar issue. In my case it was a blown chip that could be replaced very cheaply. Jim could not have been nicer or more helpful.

Hi all , I'm not to electronically inclined so I really can use some help . I have a chapion pub machine when I hit the ball up the middle at the heavy bag it only works intermittently. I checked all the wires and connections I think everything looks good.
When I go into the test menu and I do a single switch test, the switch does not close. The switch matrix in the manual looks different then the switch matrix in the game.
There are a lot of switches that are closed that are supposed to be open and vice versa. When I traced The wire back to the CPU board I noticed that it was plugged into the wrong socket. It was supposed to be plugged into J206 but it was plugged into J207. In the manual it says J207 not used I'm not sure if this could have damaged the board. Thanks for your help image.jpgimage.jpgimage.jpgimage.jpg

Hi Bob!
You might have better luck getting some help by starting a new thread in the modern games tech subforum with something like "Champion Pub switch matrix problems" in the title. People who know about that stuff probably won't be looking here.

Hope you get your game working correctly again.

Thanks I'm going to do that.

Glad to hear you are back up and running!
That's the exact same repair that Jim from Rottendog helped me figure out. Also bought the replacement chip from K's.

Apparently that chip can blow if lamp or solenoid voltage gets into the switch matrix. If you have a short somewhere between the different wire systems, it may blow that chip again.

A 74HCT.... can't handle enough current to support this function.
Here is a shameless copy from a posting on Google Groups by Ed from G.P.E.:
"Predriver for transistors... you don't want LS, HC or HCT. These have high output current requirements -when used as a predriver-.
You want to use a 74xx, 74Fxx, 74Sxx or 74ASxx. 74Fxx and 74Sxx tend to be easiest to find.
74Fxx and 74Sxx tend to be nearly identical to each other."

Here is a small copy from the schematic.
U17 isn't on the CPU, but on the driver board in the switch section.
System-7_Switches.jpg