24 Phoenix Symptom: Static garbage on screen Work: Top board is definitely genuine Taito, bottom board is a bit darker with no markings so maybe a bootleg bottom board. Running with the fluke makes no odds so maybe the processor is fine. Pulled roms and found two with broken / breaking legs (IC45 & IC49). Replaced these two roms and game works. Not all the sounds are present though. For consistency, also changed the roms at IC48/52/39/40 to Taito roms so it matches the top board. Current roms not in mame so kept a copy for reference. Okay, game now playing but missing the ships barrier noise, the birds "woo-woo" noise (swooping noise?) and also the noise of the aliens as they climb down to you is totally wrong with parts missing. Found some information on the net somewhere about which chips do what as follows (so thought I'd repeat it here for convenience): IC5 (Active High) IC6 (Active High) Pin Action Pin Action 19 Barrier tone (bit 0) 19 Alien swoop / hit tone (bit 0) 2 Barrier tone (bit 1) 2 Alien swoop / hit tone (bit 1) 16 Barrier tone (bit 2) 16 Alien swoop / hit tone (bit 2) 5 Barrier tone (bit 3) 5 Alien swoop / hit tone (bit 3) 15 Alien hit explosion trigger 15 Alien hit explosion trigger 6 Bird "woo-woo" trigger 6 Alien swoop trigger 12 Music tune select 12 Ship fire trigger 9 Music on 9 Ship explosion trigger So, looking at all the outputs of IC5 for the barrier showed no problems, and this then feeds onto IC13 (an LS163). Using the comparator on this showed that none of the outputs were doing what they should so this IC was removed, a socket put in (in case it wasn't the duff chip after all) and a new one installed. With this the barrier and the bird "woo-woo" noise returned. The swooping noise was not so easy. All the controlling ICs looked and checkout out just fine so I had to move on to the analogue section. After prodding about for a while I piggybacked all the 555s looking for any kind of change in the noise produced. Unbelievably, while I got some other interference too (to be expected from piggybacking a chip in an audio section), the swooping noise was now correct. Removing them all in turn showed that it was the 555 at IC51 that was at fault. Replacing that fixed the fault. BUT, the game now seems to periodically reset. After swapping rom boards, discovered that the reset fault now lay on the rom board. After checking out the roms and rams i realised that as the legs on the filter caps are very long, one had bent over and was now touching a leg on rom no. 8. DOH!! So, I ensured all the filter caps were away from the board and we then had no more reset problems. Put the game in the cab to burn test it. After an hour the ship explosion vanished. Grrrr... Okay, turned out it was another one of the 555's. This time around it was the turn of the one at IC42. Replaced it and all the missing noises were back, so back it goes on burn test. Still getting resets on this board. Sockets are all of the rather shitty kind so I replaced all 8. I also replaced the filter caps in between the rom sockets to get shot of those long legs. Half of them were breaking off anyway! Appears to now be finally fixed. Parts Used: 2 x 2716 (6 programmed total) 4 x CPU standoffs 8 x 24way 0.6" sockets 1 x 20way 0.3" socket 1 x 16way 0.3" socket 4 x 8way 0.3" sockets 8 x 0.1uF filter caps (ceramic disc) 1 x 74LS163 2 x 555