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.slyngs...@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