Just for reference, the resistor on a Bally board is 270 ohms between the battery and the RAM. Nobody changes that resistor, so 270 ohms would be a fine value to use.

After seeing you do this a few times on Ninja videos i am now using all coin style batteries on all my boards. I really like that setup, cheap, easy, effective. My -35 and s6 test boards have been going on at least a year now with cr2032. I have probably sent out 100 MPUs with them installed and no reports of early failure yet. I just do bally and wms SS though.

I did put a cr2032 in a TSPP to test as well. That is only going on 2 months though. We'll see.

There is a blocking diode already on the sys 11 board. You have to add a diode on a games that used a rechargeable batter, like early bally.

I always check to make sure the diode isnt shorted when i install a cr2032.

I am trying a cr2032 in a gtb 80b. I noticed the battery powers a few more ICs besides the RAM. 2 months or so and no problems yet. Voltage is steady.

The ram is hard soldered in and the real time clock wouldn't run.

For what its worth in my real world playing around. A 6264 ram holds data at 2v. Battery or cap under 2v and you start to get factory settings.

A 5101 RAM holds data even lower. It will hold data at 1v and over. Also the 5101 RAM scrambles pretty slow. After 30 minutes of no battery, in a bally game half of the data will still be saved right.