Hello, I was away when you posted this and showed to L Oliveira. As you stated that was PCM RAM, and the other is the backup RAM.
You'll need to check all control lines as well as address and data lines. Check out this diagram: https://www.retrosix.wiki/hardware-overview-sega-mega-cd
No worries. Right before you replied, I just found three severes traces from a leaky capacitor. And those 3 traces go directly to the the Program RAM.
It's a lot easier to find this stuff when you're checking the correct ICs. Who knew?
Thank you for the reply, and I appreciate that 240P test suite. It was a life saver.