Turbo Duo will not boot to internal System Card

[neSneSgB]

I've got a recapped, RGB modded, and region modded Turbo Duo here that only boots to a white screen if no HuCard is installed, as if there is no internal ROM/backup RAM present. If I put in a card, it will boot to that no problem and play fine, except that it will not detect any backup RAM present on the system. If I use my Turbo Everdrive to boot the System Card 3, not only does the CD system not work, but the save menu will show white blocks instead of the Japanese text. At one point while trying to fix this, I was able to gently flex the board somehow that made it start working perfectly fine again for a day or two, but it has gone back to not working. Also, if I hook up the CD drive in this broken state, it will act erratically, spinning the motor and moving the laser randomly.

Any ideas on what is going on with it?

[thebigcheese]

If flexing the board made it work fine for a bit, then the first thing I'd check is for cold solders (particularly on the caps that were replaced) and bad traces.