Having one heck of a time finding a motherboard 75903904 rev A, Rudy's is out of stock on a rev b. Is there a difference in the numbers or would any s+ motherboard work?
You don't need a motherboard, you need a MPU board.
Post in the classifieds section that you want to buy a working IGT S+ 10mhz MPU board.
A lot of people cry foul about using a clear chip but it really is simple with an easy menu to navigate. You will need a set chip for the BV.
Just my humble opinion after working on the S+ for the first couple of years of my slot hobby. I'm waiting to get bombed by the naysayers..........lol.
The issue has nothing to do with the difficulty of using a clear chip, the issue is that people, n00bs especially, assume that the RAM clear chip is a "fix everything" chip, which it isn't. So, they go and use a clear chip to try and resolve a problem that has nothing to do with needing a clear chip, and end up making things worse because now their original problem remains, their bill acceptor isn't working anymore, the machine will spit out coins instead of bills to credit once they do get it enabled, etc. etc.
There are times that the clear chip will fix oddball, RAM-related issues, but in general we recommend the clear chip as more of a last resort-type fix since it tends to create headaches, especially for folks new to working on and configuring their machine.