Stern Sharkey’s shootout

This machine isn’t ready yet. I have cleaned the CPU board from the battery residues. To be able to get it clean I had to remove U202 and U216 and I put new IC’s back in sockets. Also the socket for the U213 PAL IC was damaged and exchanged, even the pins of the PAL was green. But the main cause for the board no to boot was probably the reset button. Now the CPU boots and it is possible to play the game, except for some solenoids that does not work. But the display is completely black. The Display driver board had got some dripping from the battery as well, but just in the corner round U20. I removed the U20, cleaned and put back a new IC in a socket, but it didn’t change anything.

 

I talked to the owner and the cause for the game to be put in storage a couple of years ago (with the batteries still in the holder) was that it smelt burnt and solenoids stopped working. At that time the display worked as it should and because of that I’m quite sure the display and driver are OK and the problem are still at the CPU board. Both the PAL and U202 are involved in driving the display, so the problem is most likely at the CPU board. Yesterday I found a broken trace between U213 pin 11 and U202 pin 13 but repairing it did not solve the problem. One thing that’s makes the fault finding a bit troublesome is that there are no documentation available about the PAL, it’s just a black box and I do not know anything about the logic inside. 

The burnt smell and non-working solenoids was caused by a transistor at the solenoid expander board. It was once an easy fix to get the game going again but now… Do always remove the batteries when storing a game, and do always move the batteries to an external battery holder when working with a game. It’s the single most important thing to do to keep a game alive for the future.