Re: 7712 info

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Fri, 19 Jun 2020 14:16:44 +0200 Message-ID: <c782728f-93b5-345a-83b2-150ae9fbff60_at_laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 6/19/20 12:39 PM, Baltissen, GJPAA (Ruud) wrote:
>> C64 DRAM has a high failure rate but...
> 
> I repaired a lot of boards but I myself never encountered a broken DRAM.

I had a few. Most of them were MT4264, the small rest were different 
manufacturers, no pattern visible.

>> I had a lot more dead 7708 (74LS257), 7709 (74LS258) and 7707 (7406) than their 74xx equivalent.
> 
> I have seen a lot of boards but I was a bit surprised by the number of 77xx ICs. I know about the 7711 but I never saw a 7707 for example. So I wonder, how rare are these? Or were they mainly used in the USA and not Europe?

They were used in Europe, but mostly on boards made in 1984/85. So you 
will find them on 250407, 250425, some 1541 and a few 264 series systems.

The 65245 was usually found in the VIC-20.

  Gerrit