Ok, so after some thought about this matter, I've decided to write about my brief interview with the son of one of the engineers at Power Designs. Spoiler: There isn't a great deal of new info about PDI as a company here, but some of you may find this interesting anyway, as I did.
The gentleman I spoke to is the son of Arthur Silver. For those of you who may have never heard that name before, he was the man who is credited with inventor status regarding the Uniply patent. The early Power Designs models had "patent pending" screened on them, before "Uniply" appeared on most of the models. I am quoting from memory here, but IIRC the patent was awarded in 1971. However, the patent process (as no doubt some of you know firsthand) can be a long and tedious process, and it was likely even more so in the 1960's. My interviewee (henceforth called "Sonny" to give him a modicum of privacy) was very young when Silver first started working for PDI, but he seemed fairly certain that his father had been an employee of the company, rather than the owner or founder. He was unaware of his father's status as stated inventor of the Uniply, and it seems that since Silver was working for PDI at the time of the patent request, the company probably had some contract with him that specified that the inventions produced under their bannerhead was their property. This is, of course, something design engineers commonly sign off on in order to have access to advanced equipment, materials, and funding for their work.
At any rate, we can be fairly certain that Silver was working for PDI by the late 1950's. He was not a man who brought his work home with him, so to speak. I did ask whether Silver had been "chummy" with the other engineers or his boss, brought them home for dinner, etc. It seems Silver kept his home and work life separate. I had hoped to get the names of other engineers, techs, or coworkers that I could cross-reference and later possibly interview, but it doesn't seem that they were exactly fixtures in the Silver household.
I will toss up for consideration the possibility that Silver's work was considered of a sensitive nature, due to its applications and PDI's status as govt/mil/space contractor, and that PDI actively discouraged discussion of their products and designs outside of the laboratory. I do not have much to support this inference other than that I and others have been able to find almost nothing about the company itself. The only other name I have found in association with PDI is that of Melvin Becker, who seems to be associated with the change in location of manufacture to Connecticut. This latter was the place where the very-different-looking precision models seem to have first appeared (the 5020A and the 1001A are a couple of examples). These seem more similar to the 611X models produced by Hewlett Packard in form if not in function: Those cool looking concentric knobs must have appeared rather old-fashioned to eyes of that time period, and in the latter days of the Cold War period it was very important for any US tech company to keep up appearances of being on the knife edge of manufacturing and design. I do not know what happened to PDI by this time, but it appears that this change in format to a modern interface was not a "big hit" with industrial purchasers. Perhaps by then Power Designs was synonymous with tank-like appearance and build, and engineers familiar with earlier models were not as trusting of the new, plasticky models (with the older form factor, to boot: I've noticed that the newer models seem to be using the analog meter style that shows a vertical "arc" to the left of the needle, rather than the straight-up-and-down vertical meters. This was the older style of meter; If you search you can find some 5020's for example that have the arc meter style, but don't have the Palo Alto printing on them yet). Some have supposed elsewhere in this thread that this later incarnation of PDI was merely repackaging older stock and putting a new face on it to present the appearance of a newer, more advanced model. If true, this was unlikely to have gone unnoticed by the engineering community, and may have undercut the perception of the company's integrity, warranted or not!
It is also significant that Silver himself had almost certainly moved on by that time anyway; I'll get to that in a moment, as I'm back to referencing the 1960's decade here. Sonny told me that his father was, unsurprisingly, a very smart guy. He volunteered that his school science projects he and his father built together were the marvel of the teachers and students (one of them was a lie detector; although I didn't ask Sonny exactly how it worked, I can only imagine the stunned faculty members watching Sonny walk into the science fair with a homemade polygraph in a box under under one arm). Silver was given to improvising solutions around the house, as well; Sonny recounted his father melting down fishing weights and pouring the molten lead into beer cans to create counterweights for a home designed pulley system Silver used to operate a door he had added to the house. His children were also recruited to assist with these home improvement projects. One of the stories I heard is that Silver decided he was going to do some excavating in his backyard and the kids were all handed shovels to dig it up by hand. I think it's notable that this guy was the sort of resourceful individual who wasn't going to hire in a bunch of outside operators or contractors to get things done; he did it himself or had his immediate family pitch in to help, and he could work with whatever was at hand to accomplish his goals. Sonny mentioned a picture of his father at work on circuits at his desk wearing a bow tie; while I haven't yet seen it, I hope to be able to post it here if and when I can get his permission to do so.
I asked Sonny about his own background and whether his father talked often about Power Designs. He told me that he was a child during the time period that Silver worked for PDI, so he didn't hear much about it. However, he did tell me that his father came home from work on more than one occasions very excitedly talking about the new laboratory he had access to. Apparently, they had a room where he could test the circuits he was building at very low temperatures, and one can only assume that the circuits were working well under those conditions, because Silver seemed very happy about this development and new access, rather than frustrated or concerned.
For those of you who've read my earlier post, Silver was at some point awarded a gold pin for his contributions to the Apollo Program(s). Maybe he could not be honored in other, more public ways, because of the Space Race and the need for the US to keep its best engineers' identities a secret from foreign interests. I don't know. But again, the fact that Silver was working on power circuits in a cold lab suggests that this might well have been meant to simulate how the circuits might function in the extreme cold and vacuum of space. Sonny did say that he recalled his father saying that one of his designs actually went to the Moon. It would be almost comical to see a picture of Armstrong or Aldrin supported in the background by the image of the iconic PDI robot with his hand up, limiting current, and the words "patent pending" beneath.
I apologize for the fact that I have made so many guesses in this post. Should more information come to light (and I do hope it will!), I'll happily edit what I've written here. I have likely made some errors. I did my best to keep notes as I talked with Sonny, but the time periods between Silver's tenure at PDI and Venus Scientific isn't clear (may have even overlapped?). Sonny did volunteer that he'd see if he could find any of his father's stuff related to PDI, and asked me to update him as well. I think he was more than a little touched that so many people thought so highly of his father's work and designs (and I'll make one more guess; that for security reasons, among others, Sonny had never been told just how important his father was as an asset to the programs he worked on). I'm hoping that some of you will also continue the effort, as eas and Greg have, to bring the real story of PDI to light, and I will continue to post with any new info I can find myself. I also intend to send Sonny a copy of this thread so that he can see how this thread developed, from someone asking about a recommendation for a lab power supply, to almost a detective novel.
Thanks to all who have posted in this thread thus far.