OK, having problems with a Data East Rocky & Bullwinkle not booting.
All original boards, no hacks evident, no battery damage I can see.
The 5volt LED came on the MPU board, but it would not boot.
Checked the 5v and it was actually low, under 2v.
Replace the power supply with a brand new RD 005 board and now it finishes the boot sequence, even to the point I can just access the Adjustments menu, but then it freezes.
Turn on, the PIA and 5volt LEDs come on.
The PIA LED then turns off and the Blanking LED comes on.
The game boots, then there is a flurry of solenoids firing, the Blanking LED turns back off and the game freezes completely. The 5volt LED remains on.
Is this maybe bad PIA(s) on the MPU board?