Electronics > Projects, Designs, and Technical Stuff
1960s pellet parts
Alex Eisenhut:
I took a picture but it's not the greatest.
Interesting. My 1S1 manual doesn't call out embedded components, but the schematic matches my s/n 001897 1S1 which came from McDonell-Douglas (makers of the F-15! w00t!)
The schematic in the field training package has different values for C88/C89, and are also called out as embedded components. (So in some 1S1s it's more than just R4 C4 R5 C5.)
As you can see my 1S1 has the 15pF ceramic caps.
I think that the vias/solder blobs pointed by the red arrows are actually where the two pellets are inserted from the other side.
I'll bet that R4//C4 is one pellet, and R5-C5 is another.
I'd have to remove the PCB and look underneath but that is not in my plans right now.
LaserSteve: I don't see the connection. Tektronix also made their own PCBs and CRTs. That doesn't mean I'd expect to have embedded components in a PCB.
Edit: A simple test occurred to me, remove the connection from the delay line and check the resistance from the center pin to the input of the bridge. It measures 6.3 ohms, not 4. Shows that there's indeed something there!
duak:
Is the PCB the standard 1/16" thick material? Somewhere I've got an old board from the 60s that has some cylindrical surface mount parts although I think they were somewhat longer than 1/16".
About M-D - McDonnell also made the F-4 Phantom, and the Mercury and Gemini capsules. As it happens, when I was with MacDonald-Dettwiler I worked with a fellow who was with McDonnell Aircraft in the mid-60's during those programs. I believe he was in an electronics lab there and could very well have used that 1S1. He was also there for the infamous accident involving two astronauts: https://en.wikipedia.org/wiki/1966_NASA_T-38_crash
Cheers,
Alex Eisenhut:
Here is the whole PCB. It is a FR-4 style regular old PCB with glass weave and everything. It looks like the usual 1.5mm 62 mils. The only difference with modern PCBs is that whatever resin they used is more sensitive to heat and the board measles easily. But that doesn't change the function.
You can see a cable bundle making a u-turn in the upper left corner, there's a screw under there. I don't like moving the cables too much, but I need to remove all the screws to lift the PCB.
There's a sheet metal plate right under the PCB.
amyk:
I think it was more of an anti-reverse-engineering trick than anything else. The extra parts might be hiding under R7/R8 --- the PCB layout in the PDF linked in the OP shows the input going to another island under them, and in the picture I see something odd in the gap between them.
LaserSteve:
The connection. Is, having good ceramacists. In house would get you to SMT and hybrids early on.
In an area where ceramic hybrids were just being invented.
Steve
Navigation
[0] Message Index
[*] Previous page
Go to full version