I got two Silent Dragon PCBs recently.I never heard about this beat ’em up manufactured by Taito and a quick look at MAME lead me to try a first repair of this cool game.
Board was in quite good shape (a little bit dusty though..)
When powered it on I got a steady black screen but I could hear all the sounds and also put credits in.So I started to press and flex the board and all the graphics were restored on screen when I touched the area around the TC0180VCU ASIC.So I decided to reflow the ASIC (some pins were really lifted) which ,according to MAME source, controls the video and decode graphics:
I was quite sure that I succeeded but I was wrong since the board still played blind.Crearly there was a loose contact somewhere so I started my visual investigation on solderside.There were no broken traces but I came across this:
Two pins made contact between them and precisely the VCC pin of a 74LS245 @IC26 and pin 1 (input) of a 74LS04 @IC27.Pin 2 (output) of this 74LS04 was connected to /OE pin of the four GFX MASK ROMs and this explained why there were no graphics at all.After removing the short,I finally could enjoy also with my eyes this game.
Now time to dump the two PALs on it! 🙂