Another shoot’em up on the bench and always a board coming from Portugal : Double-Wings produced by Mitchell Corp. in 1993 (but hardware is clearly marked Data East)
The board booted into game but had a color issue, the screen was all blueish :
The brief POST showed an error related to palette RAM:
After a quick look at PCB I pinpointed the palette RAMs is two 6116 (2K x 8-bit devices)
When I went to probe with my scope the lower one @5F I found some stuck data lines:
I pulled the chip and tested it out-of-circuit.It failed:
Installed a fresh RAM on a socket :
This fixed the issue and board completely.Another repair accomplished.