Police Force
Williams, 1989I have a Police Force that came with a System 11 MPU and Road Kings ROMs. I know I read somewhere about using this board in a 11b game, but for the life of me, I cannot find the site.
I ordered the full EPROM set from That Pinball Place, which includes CPU ROM Set (U26 & U27, L-4 Sound ROM (U4), and the L-2 Speech ROM Set (U19, U21, U22). I wasn't sure I needed all of them, but better to be safe than sorry.
What do I need to do (if anything) to get the 11 board to work?
Thanks!
Pinwiki confirms the original Sys11 board will work in later generations, although you'll need to add some missing diodes and short a couple of pins to ground on J18....
http://www.pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#MPU_Driver_Boards
Or as wiredoug suggests, find someone to trade boards with you, the original Sys11 boards are getting harder to track down these days
I'd modify it as Pinwiki suggests, and use it. You never know when you're going to find a High Speed or Road Kings without a MPU, and decide to tackle it as your next project 
*then*, you buy the Sys11B board for the Police Force
The difference in price isn't *that* significant.
Yeah, that's about what I've decided. The mod looks easy, and this board is acid free.
My only question is about the diodes, Pinwiki says to use 1N4735A 6v, 1w zener diode. My local Radioshack has a 5.1v, 1w zener, or a 12v, 1w. I would assume the 5.1v should work?
yeah, not that big of a deal using the 11 in an 11B. If someone needing an 11 finds an 11B CPU it's only an amp and a couple of other small parts to revert it back to an 11. Or use an 11A which is compatible with all 4 versions.
Quoted from Jive:My only question is about the diodes, Pinwiki says to use 1N4735A 6v, 1w zener diode. My local Radioshack has a 5.1v, 1w zener, or a 12v, 1w. I would assume the 5.1v should work?
They are .15 cents, just get the proper part:
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Beckley, WV
Melbourne
Maidstone
Sana'a