aka Hyper Sports, from Konami in 1984. Its a great game, but the pcbs are quite unreliable. I had one on the bench today that just looked so close to being working but its turned into a bit of a nightmare. Hyper Sports uses an alternating field setup, after spotting some manky looking signals at several custom pins i set about tracing them. I replaced several chips before i realised that Konami doesn't follow the regular rules of signal flow, ie, inputs at the left, outputs at the right, they often snake signals around to make the symbols fit on the schems. Unfortunately i didn't have my thinking head on, and was perplexed by the signals origin. Only once i was looking at the datasheet for a ttl chip did i realise the node in question was an output, hence the problem was in the opposite direction i was heading! It turned out to be no less than three bad 2114 rams (H8, J8, H9). The sprites were still wonky, 4bits bunched up at the left side of the screen but active, the other 4 bits spread all over the screen and static. A bad 74ls163 counter fixed the bunching at the side of the screen, but i can't track down the lack of proper movement on the other 4 bits. I can 'see' the CS of the SRAM isn't right, looks like a clock problem, but my head hurts and i need a rest before i tackle it further. I had sat down to do what i thought was a quick fix, nine chips later and its still not sorted :(
Friday, 28 May 2010
Hyper Olympic '84 fixing
aka Hyper Sports, from Konami in 1984. Its a great game, but the pcbs are quite unreliable. I had one on the bench today that just looked so close to being working but its turned into a bit of a nightmare. Hyper Sports uses an alternating field setup, after spotting some manky looking signals at several custom pins i set about tracing them. I replaced several chips before i realised that Konami doesn't follow the regular rules of signal flow, ie, inputs at the left, outputs at the right, they often snake signals around to make the symbols fit on the schems. Unfortunately i didn't have my thinking head on, and was perplexed by the signals origin. Only once i was looking at the datasheet for a ttl chip did i realise the node in question was an output, hence the problem was in the opposite direction i was heading! It turned out to be no less than three bad 2114 rams (H8, J8, H9). The sprites were still wonky, 4bits bunched up at the left side of the screen but active, the other 4 bits spread all over the screen and static. A bad 74ls163 counter fixed the bunching at the side of the screen, but i can't track down the lack of proper movement on the other 4 bits. I can 'see' the CS of the SRAM isn't right, looks like a clock problem, but my head hurts and i need a rest before i tackle it further. I had sat down to do what i thought was a quick fix, nine chips later and its still not sorted :(
Thursday, 27 May 2010
EL-Wire Barbers pole
I have a project on later in the year at a certain arts festival in Nevada that i need to develop some gizmos for. One of which is involving bicycles, and EL-wire... strange bedfellows maybe, but i need to develop a controller that can drive multiple strands of different coloured EL-wire. For development purposes i don't want lots of untidy wire hanging about, so i came up with a low-tech but effective solution, the EL-wire barbers pole!
The connectors for the 9 EL-wires are off to the base at bottom left, these will plug into my controller. The fixing is super low-tech Scotch tape (sellotape :) which is useless for anything long-term, but i don't want this permanently attached. The 'pole' is just a regular mailing tube, i happned to have white one kicking around, so it helps to brighten the el-wire even more!
Next stage, to build the controller, i'm thinking about re-using the code and technology from previous flourescent tube light drivers i built a couple of years ago, or designing from scratch again. I'll probably chicken out and go for a PIC Microcontroller technology i know and trust (and have loads of spares for already) PICAxe.
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