From: J Ellsworth (c1_at_syndicomm.com)
Date: 2007-03-29 00:51:06
"Ah…. I know what this is. I did this board through Fourth Generation, a local PCB design house. That’s my writing on the labels as well as the P19 on the board. The processor was hand bonded (little old ladies with microscopes) and the lid taped on. Probably not working as I imagine the passivation was missing or bad. This is one of the boards we gave developers to produce TED type software on before the release, since TED wasn’t C64 compatible they needed something to get started on before the real product hit the shelves. The joystick connectors matched what developers would have had for joysticks (Atari style). How did it get to Sweden? We sent it there through Sig Hartman’s Software/Games group most likely The odds are that this is a PAL version though we were probably sending out monitors also to support NTSC so it could go either way. "So short answer, this is one of mine, it was to get the core chip set out as early as possible." BTW, the gentleman that was asking about fixing this should be able to fix it by talking the processor, TED chip, etc out of any working TED family product. Probably easiest way is to test the power supplies (two fuses, two sources) and then swap chips. Weird to see my handwriting from when I was 24 years old, 24 years later." "Reading backwards, someone asked about the resistors vs the diodes. I did switch to diodes as the whole goal was prevent the hi-z input from getting above VCC which would trip the test mode (if it sounds squirrelly, it sort of was). I proved that the problem was that they weren’t effectively terminating the pins inside the chip by adding pull-ups which lower the impedance basically to the value of the resistor. Diodes are lower impedance yet when forward biased, so these would have strapped these inputs to one diode drop above VCC keeping them out of test mode in spite of the strength of the interference field. (You could do a moiré patter by holding the board next to the monitor because the monitor interfered with the graphics chip which in turn changed the monitor which in turn changed the interference, etc. etc.) They might even be germanium, it would be interesting to see." Message was sent through the cbm-hackers mailing list
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