Re: 7712 info

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Thu, 18 Jun 2020 21:48:48 +0200 Message-ID: <5f75c60e-ea2a-843b-1ac0-e116252e99af_at_laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 6/18/20 9:42 PM, Francesco Messineo wrote:
> On Thu, Jun 18, 2020 at 9:36 PM <silverdr_at_wfmh.org.pl> wrote:
>>
>>
>>
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>>> As for reliability... They did work, but it seems they don't age well. But that's OK after more than 30 years.
>>
>> Might it be that I mixed something? Like.. RAM chips? I vaguely recall that MOS once made replacements for some otherwise common parts and that didn't go too well in terms of reliability. But can't be sure now if/what those were.
>>
> 
> The only MOS-branded RAMs that I have seen are the MPS6550 1k x 4 bits
> static ram, and the MPS2114 1k x 4 bits static ram.
> None of the two is particularly reliable, but I do have 78xx
> date-coded chips still working fine as of today.

Yes, but often, if you have a dead C64 with a lot of 77xx chips on it 
it's one of those that is the problem (unless it's the PLA, but that is 
also known as '7700-xx' or '8700-xx').

  Gerrit