9 Jun
2020
9 Jun
'20
11:19 a.m.
Interesting, good to know!
--
Anders Nelson
On Tue, Jun 9, 2020 at 1:04 PM Ethan Dicks via cctalk <cctalk at classiccmp.org>
wrote:
On Tue, Jun 9, 2020 at 10:46 AM Jon Elson via cctalk
<cctalk at classiccmp.org> wrote:
DEC's transistorized machines used +10V and -15V supply rails for the
logic, and some other large voltage (+28V?) for the core.
Later machines still used odd voltages. Lamp-based PDP-8 front panels
used voltages like +8V, and later core was IIRC +20V.
There are a couple versions of the PDP-8/a PSU, for core memory and
for MOS memory. MOS memory is standard 1970s triple-voltage stuff
(4096s and 4116s) but they pull a lot of +12V compared to later
machines.
It's often easier to just fix the old PSUs than replace them. At
least linear supplies aren't so hard to debug.
-ethan
On 06/09/2020 09:27 AM, Anders Nelson via cctalk
wrote:
> Related question: Is there any reason, other than historical accuracy
and
> cost, to not replace the power supplies in
vintage computers with
modern
switching
power supplies?
The old discrete transistor machines often used fairly odd
voltages, not like 5V and 12V.