OK, you all have Signature analyzers, right? and you have a small pile of sick Asteroids, right? Do you have a working one? I think I might have found a way to check out the !@#$@# loop in Asteroids using Signatures but someone is going to have to help with the research. I'm just trying to get rid of fixing the darn things as service headaches... Results to date: Start with a working Asteroids board, put it in your bench and feed it 5VDC. Find the two self test switches, the main one to get the grid and the second one that creates a diagonal line, and turn both on (pull Low). Clock -ve Phase 2 clip Start +ve A9-1 (HALT - when Low) Stop -ve A9-1 " " Now you should get Sig 3H16 on Vcc, and 0000 on Gnd. OK? Now you will find that you get stable and different signatures on the data pins for almost all the IC's!!! I have experimented with having just the 1st self test (grid) on and checking the Sigs, if all DIP-8 switches are on then you get Vcc 1P90 and D11-9 (DAC) PAA6, and if all switches are off then you get Vcc 3958 and D11-9 17HH. Note that this does not care which version of main program you have! I forgot to check with the other version of Vector ROM so your mileage may vary, but it sure looks interesting! I shall be having my apprentice tech going through the board and get the Sigs for as many points as seem to matter beyond the basic Sigs that Peter Frey (sp?) created. Perhaps I'll post them if we have the time...but you can get rolling fast with what I've given you tonight. Anyone want to tackle the FLUKE 9010A Signature headache?? John :-#)# PS - I'm going to post this on RGVAC to troll for more techs for the group.