Quoted from hokie2764:I also checked the rating of each fuse (except the one on the high voltage board). All fuses seemed to match the recommended rating except F6 - according to the manual and the machine it should be a 3A slow blow, but mine appears to be a 5A and I don't see or know how to tell if it is a slow blow.
There's a note in the manual on page 28 that Space Invaders specifically uses a 5A SB fuse in F6, while others normally use a 3A SB.
Slow-blow fuses will be labeled MDL, MSL, or 313, while fast/normal blow will be labeled AGC, 311, or 312.
Li, NY
