On 3/8/21 6:39 PM, Jim Brain wrote: > On 3/8/2021 11:29 AM, Bill Degnan wrote: >> Hi, >> I have a strange C64C (I believe) motherboard with: >> >> PCB ASSY NO.250451 >> PCB No. 251915 Rev.2 >> >> ...printed on it. I don't see this board documented in the normal >> places and the PCB does not come up in a search, any ideas? The VIC-II >> is missing. >> >> https://www.vintagecomputer.net/commodore/64C_250451/250451_251915_pic1.jpg >> <https://www.vintagecomputer.net/commodore/64C_250451/250451_251915_pic1.jpg> >> >> >> Thanks >> >> Bill Degnan >> > That's an odd one. Like a CR board, but with 8 DRAMs, though not ina > 2x4 config like on the 466 board. The numbering suggests that it's older than the 250466 design. Same goes for the datecodes on the chips on it. But it shows a lot of details that later appeared on the 250469 boards. It would be interesting to know which VIC goes onto that board, is Pin 13 of the VIC socket connected to +5V or something else? Where does the 6581 SID gets the +12V from? My guess is this board was supposed to replace the 250425, but they ran into some kind of problem(s) and had to make the 250466 as a stopgap until the 250469 was ready. GerritReceived on 2021-03-08 20:00:03
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