Re: C64 PCB

From: Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de>
Date: Sun, 07 Jul 2013 20:16:51 +0200
Message-ID: <51D9B093.8070705@laosinh.s.bawue.de>
On 07/07/2013 07:59 PM, silverdr@wfmh.org.pl wrote:
>
> On 2013-07-07, at 19:28, Gerrit Heitsch wrote:
>
>>>>> BTW - I am surprised that there is no picture of your "KU" there ;-)
>>>>
>>>> No idea why... But you can find the KU on the web if you look for it.
>>>
>>> There is also the 250441 missing. Do you know how it looks?
>>
>> Never seen it.
>
> Service manual says:
>
> The 4th version of 64 board [...]
> All circuits remain the same as the 64B (Schematic 251469)
> with a few component location changes:
>
> 1) Resistors 28, 29, 30, 36, 48 were reduced to Resistor
>     Pack RP5.
> 2) Diodes CR100-105 are no longer piggybacked. Their new
>     locations are CR9, 12-16.
>
> So I presume it is physically almost the same as 250425.

Sounds more like an intermediate between 250425 and 250466 with still 8 
RAMs but also the IEC protection diodes now having their own place and a 
few resistors combined in a resistor pack.

Maybe it was ready to go but never made it out the door and they 
switched to the 64Kx4 DRAMs (and therefore the 250466) right away once 
they were cheaper than the old 64Kx1?

  Gerrit





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