21 Jun
2021
21 Jun
'21
11:53 a.m.
On Jun 21, 2021, at 2:43 PM, Chuck Guzis via cctalk
<cctalk at classiccmp.org> wrote:
On 6/21/21 10:55 AM, Paul Koning via cctalk wrote:
memory. Nobody explained why that was a
real problem.
> Core memory is fairly sensitive to
temperature. In the case of the 1620, there is a heating system that brings the core
memory box up to its operating temperature, which is why it takes several minutes after
you turn on power before the machine will run.
> Possibly the fan problem meant the
temperature control system was no longer adequate.
For some (jprobably hallucinatory) reason, I thought there was a project
at CHM to replace the 1620 core stack with semiconductor memory. Guess
that never happened.
--Chuck
Perhaps you were thinking about the CDC 6500 at the late lamented LCM? That got some
replacement stacks, which was an interesting puzzle because the read data connection out
of the memory modules is a differential analog signal carrying the sense wire data, so the
replacement module had to produce signals of that form.
paul