Unexpected marking on P2 module

[retroleds]

This was one of the rubber coated, early P2 modules . I was so intrigued over the TRW marking(very clear and stylized when in hand) that I dug thru my dead module box and pried display off three of the early modules with the "boat propeller" shaped contacts and the horizontal light sensor. I found one more marked TRW - seems the ones that are in the plastic assemblies that are only notched out for the qurat crystal on the front side are TRWs. The next ones have an oblong hole for the crystal and the circuit paths are rather different. Crystal on the first one is marked 4-72 I apologize for murky picture, was having a hard time bringin out the gold print. I can redo under the microscope if anyone is terribly interested.



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[LEDluvr]

Wow -another piece of history in the Pulsar Puzzle.
I can't help but wonder if the TRW components were manufactured at their facility in Redondo Beach, CA?
I don't think there is a way for us to find out, but since I grew
up blocks from their sprawling campus, I can't help but wonder....

[bruce wegmann]

Speaking of unexpected markings. I had a clock chip package that had detached from the circuit board [this was out of a P3, BTW], and decided to indulge my curiosity and see what the clock chip looked like. I heated the package with a torch until all the epoxy encapsulation burned off. Under the microscope, along one edge, the chip was clearly marked "PULSAR", in the same lettering style that appears on the top of the brown clamshell boxes. But then, in equally clear letters, immediately to the left, it says "HUGHES 1973" (!). Now, I was brought up to believe that only RCA made clock chips for Time Computer; never do I remember any mention of Hughes. I know they made chips for a number of other watch manufacturers, but I don't recall any Pulsar connection. I'd love to post a pic, but I have no way of taking one through my microscope [it only goes to 90X, anyway, and you'd need at least twice that to see it well]. There is also no RCA logo on the chip package...but there can be no doubt that Hughes made these chips specifically for the Pulsar watches, and no others. Check your dead P3 modules...there have to be others out there...[of course, I thought that about the Hamilton-marked P2 casebacks, too, and haven't seen another one of those yet, either... A good picture would be very interesting.

[Handy]

TRW manufactured RF Power modules back in the 1970s. They were surface mount devices in encapsuated cases.
Cheers,
Ian

[retroleds]

Got staring at this thing even more...at top of circuit in more gold lettering. H.W.Co. 8-71 Wow! This thing didn't have battery labels for polarity, it has + and - nicely molded(raised) into the plastic inside battery ports.

Seems I've seen Hughes inside of a Pulsar on the chip while working under the microscope.....probably in the early years before I understood the oddity of it.

[azimuth_pl]

I decided to return to this thread after some additional analysis.

the picture below is of the early P2 rubber-potted module which seems to be a following version after the one shown by Ed.
the circuits are a bit different and the plastic already has an oval opening for the quartz.
the substrate is marked Pulsar 2925 1-72.




what's the module number on the one marked HWC 8-71?

btw. while webmastering my previous website I might have invented the phrase "2800" in reference to the early P2 which is very likely not correct based on Dennis' input. some people have started to use this coding but I'm not sure if I quoted 2800 from some place or if I simply downgraded the number from the 2900 being the later P2.

so, as the early P2 clearly indicates 2925 and the later P2/P3 substrate shows 3005... then does anyone have a reference table for the modules?
oldpulsars doesn't differentiate any of the P2 modules although it now seems there were 3 versions.
I'd like to have a clear understanding on the modules used in order to differentiate them once and for all.