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

From: Bill Degnan <billdegnan_at_gmail.com>
Date: Mon, 8 Mar 2021 13:23:09 -0500
Message-ID: <CABGJBuf3anfWjPy--b9_xLSpeEUjoS4OgunyBSn16rKeztfWrA_at_mail.gmail.com>
Terry,
It's that brown ceramic type.  Look at the image in hi-res from
vintagecomputer.net
Bill

On Mon, Mar 8, 2021 at 1:20 PM Terry Raymond <traymond160_at_gmail.com> wrote:

> Hi Bill,
>
> Is one chip there a ceramic chip?
>
> 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 20:01:14

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