Hi all,
Currently have a Twister, and a Last Action Hero on order to be delivered later this week. Posted this question in the Twister club forum as well:

I'm finally getting around to replacing a couple ROM chips in my Twister to see if that improves spinner/fan functionality. I had trouble pulling the ROMS which is why I took so long as I didn't want to break anything. Finally was able to figure out how to extract existing chips without causing damage.

Here is what I got:
TWISTER (SEGA) EPROM U210 GAME A4.05
TWISTER (SEGA) EPROM ROM0 DISPLAY A4.00

I replaced both in the game, but when I turned on game it doesn't appear to boot. Lights come on, but game doesn't start. Removed the new main ROM (but left display) and replaced with original, and game booted after asking me to open door.

Question 1: Is there something I should be doing to help it boot with new ROM chip, or is it missing something else that needs to be added for the new ROM chip to work?

Question 2: Aside from display working as expected, how can I check that updated ROM is functioning properly, what has changed?

Any advice appreciated.
Thanks.

Wow,
I seriously thought they were both made by the same company...

m_miscon (resized).jpg