Re: Attempting to ID an odd C-64 c (?) motherboard

From: Mario Kienspergher <contact_at_kinzi.net>
Date: Mon, 8 Mar 2021 19:21:02 +0100
Message-ID: <62e03602-84dc-9593-4e85-349f0a45a0dc_at_kinzi.net>
Am 08.03.21 um 18:39 schrieb Jim Brain:
> 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.
>
Indeed, looks like they were testing it but trashing it because of 
problems, as the 250466 came much later with a NMOS VIC and old glue logic.

IC-stampings are from mid/late '84. Maybe the HMOS-II-Version of the VIC 
did not perform very well or the yield was too poor, or known problems 
with other HMOS ICs (7501, 7360) forced postponing.

Anyway, a sensational finding. Where did you get it from, Bill?

-kinzi
Received on 2021-03-08 20:02:38

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