What mpu will work in a double five times

[billhood]

My 504b mpu is bad. having trouble finding a used one.  what other boards that are comparable or better can I use?

[qbert]

Bill,
That depends on your game's configuration. If you have backlight reels with a multimedia board having enhanced sounds I would not recommend a different 500 series board as you may be disappointed with the hum coming from the speakers with a different board. If you don't have either of these than any 500 series board will work fine. You can also switch to a 1270 board with a legacy adapter card but you will have to change the backplane board also.

Lastly I can't believe one of the fine vendors on this site doesn't have a 504 board for you to purchase.

Rich

[Retro tech repair]

Someone here has probably got a 504 board. i know i have ran out, and all the machines i have been getting in have a 1270 or pre 504 board. So i can see there being fewer of them out there.

[billhood]

Thanks for the information .  I'm not opposed to going to a different board. I don't have enhanced sound on this game.  the board is flickering the display between door open mb, call attendant ,  door open mb, etc. voltage on the battery is 3v, no varta battery. opening and closing the door has no effect. I've swapped door optics with a known working set, reseated all chips, run a clear chip, etc. no change. 

[Retro tech repair]

I have had that problem befor. Don't remember how I fixed it tho.

[qbert]

Make sure your belly door and cash box door switches are disabled or properly adjusted also. With no enhanced sounds a 502 should work fine.
Rich

[billhood]

Yes, switches are bypassed and I get the correct continuity on each switch to the backplanes.  I'll look for a 502.  Thank you!