On 3/8/21 7:16 PM, Terry Raymond wrote: > Hi Bill, > > Is one chip there a ceramic chip? All 8 RAMs are ceramic. And the CPU, probably an early 8500. Gerrit > > Terry Raymond > > > On Mon, Mar 8, 2021 at 11:12 AM Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de> > wrote: > >> 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. >> >> Gerrit >> >> >> >> >> >> >Received on 2021-03-08 20:01:53
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