Hello Pinside!

I'm trying to help a friend out with his dirty harry. It's exhibiting some switch behaviors I haven't seen before, when you think it's all about the optics, then one of the physical ones throws you for a loop.

When everything is connected, the switch test shows rows 1,3,6 and 7 all closed (pic1). If we disconnect the optics by pulling off J3 from the 16 Opto Switch board A-169998, all of those rows return to normal (except the opticals that show show normally closed of course). We've traded out that board from my ST:TNG and the behaviors don't change, so we don't believe the problem is in the board.

When we pull the J3 from that board, and then test individual switches, switches 11 through 28 function fine (columns 1 and 2), when we go to test any other physical switches, for example - #61 Left sling, it will show as row 1 completely closed. (pic 2)

I *think* the switch matrix ties back to U18,U19 and U20 on the Security CPU board (Pic3, lower left) - U20 was recently replaced, should we replace U18 and U19, LM339's?

Is it possible to trade out the security CPU board from my ST:TNG with the Dirty Harry one? They are similar, but dirty harry has the batteries off the board and on the side of the back box.

Thanks for the troubleshooting directions!

Glenn

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I really don't know what to suspect, I mention the Security CPU only because of U18 and U19, I think we suspect them more than the CPU on that particular board. The entire CPU security board for dirty harry is A17651, and for ST:TNG A12742.

The manual for dirty harry mentions:

The game uses a new Security CPU Board that is not downward compatible to the CPU boards used in previous games. The new board has an added security chip that can be interchanged between other DIRTY HARRY games and software revision levels. The CPU board itself is interchangeable with later model games, but must be equipped with the correct security chip and software for that specific game. ---- So, as I read that to myself now, it seems like I can't pull the entire CPU board out of ST:TNG and put it in dirty harry......