Ran through self test OK, came up with chequer board screen and then reset most of the time. Occasionally would start game, but with credit noise continually playing and credits rapidly counting upwards. This is caused by CPU 4 (E5) not running properly. checked the eprom and ram (C5,D5 and E5) and ram was faulty. replace ram chip solved the problem.
Replacing the eprom at 4C with the equivalent one from Galaga (gg1-2 or gg1-2b.3m depending upon the bootleg) , the name will be changed to Galaga and the copyright message back to normal. If you also replace the eprom on the video board at 5R with the character rom from Galaga (gg1-9.4l) then the logo will be back to normal as well.
You can also fix the off-white colouring by replacing some of the resistors on the video board. Check out Jrok’s web site here for instructions on this.