Quoted from ss-pinball:
What is the preferred battery solution for an original board...pros, cons...give it all to me.
I'd like to avoid AA batteries, even off board.
I'd like to avoid the NVRAM/ROM conflict.
What is the preferred fix?
While I think NVRAM is the best for running the alternate updated version of the code I think the question would be more toward what would be the best battery option to use so that any version (even original) will run on the board. For that I see a few options:
- Run NVRAM (limits use of original ROM's)
Great option for new code but if you want to start out with the original code or go back to original code then the NVRAM has to come out. (leave circuit as-is)
- Run the original style rechargeable battery. (not really an option and I wouldn't install one if asked...)
Just listed for completeness sake. Would leave the circuit as it.
- Use a remote AA battery pack with three AA Energizer lithium batteries. Plenty of capacity for long RAM retention.
Not a bad option but I would install a disconnect so the board could be easily removed if needed without a large battery pack dangling off. Board needs blocking diode added to prevent trying to charge the AA's.
The next two options are popular but the concern is that the MPU-200 has TWO 5101 RAM chips to twice the load. How much will that
- Use a large memory capacitor (easy to install, no other board changes needed)
A good option for some but I'm not a fan since I don't think it will hold settings and scores as long as I'd like and the extra drain with the 2nd RAM will decrease that further.
- Mount a coin cell holder for a CR2032 type battery.
I think this may be a good option since the batteries are easy to get, replace, and don't tend to leak. Have used them many times for people but just wondering on the current draw and life with two of the 5101 RAM chips. This also needs the blocking diode installed to prevent charging the coin cell. I would lean toward this option but would like to hear if anyone else is using a CR2032 on the MPU-200 and how long it lasts. If you're talking at least 6 months to a year then this would be fine.