18 Jul
2018
18 Jul
'18
9:44 a.m.
Thanks for the response. I had seen your info on the two other parts.
Unfortunately, I have no idea if these system modules exist outside a
museum.
I might have to back off even further and work out a technique on
something like the B301 or B611 modules, which seem to be obtainable
and at least vaguely similar to the transformer circuits I am
interested in.
Can you detail a little more what your measurement method is? Do you
have an LRC meter or something, and measure the resistance +
inductance open-circuit? At what frequency?
--Joe
On Wed, Jul 18, 2018 at 9:39 PM, Vincent Slyngstad
<v.slyngstad at frontier.com> wrote:
From: Joseph Oswald: Wednesday, July 18, 2018 12:15
AM
I'm trying to model the PDP-1 DEC system models, first with SPICE
(ngspice on Linux), then with VHDL.
The spice modeling of flip-chip modules has been an interest area for me. I
imagine that's similar, though perhaps less daunting, than modeling the
earlier system modules. Flip chip schematics, etc. can be found here:
http://www.so-much-stuff.com/pdp8/flipchip/flipchip.php
and some of the spice model stuff here:
http://svn.so-much-stuff.com/svn/trunk/spice/
Particularly a parts library and the Perl to extract information (netlists)
from the Eagle schematics. There are sub-directories with results from the
Perl for red and blue handled modules, and a few of the green. Finding data
to fill in the component model library is "fun",
as the parts are long obsolete, and data sheets are hard to find.
I also lack the EE skills to be effective at converting the data sheets into
spice models, even when I can find them.
Your first "fun" step might be to locate module schematics and convert them
to a useful form.
I'm struggling to understand the properties
of various transformers in
the system module circuits, most importantly (at least, the ones I see
in schematics I want to model)
Those are all earlier than the info that I have, which is mostly for the
T2037 and T2052. Perhaps the earlier ones are wound on a similar core, or
the measurement technique Josh and I used can be used to begin to reverse
engineer them:
http://www.so-much-stuff.com/pdp8/repair/pulse.php
Is there any source for information about these?
Basic specs? I don't
even know what the turns ratios are for these parts, much less
plausible inductances, so my spice models misbehave pretty badly.
Unfortunately, the schematics don't usually state the relevant specs
(just part numbers), so it may be necessary to measure up originals.
(Hopefully in-circuit.)
Vince