curiousmarc

Original manual for our PM receiver found!

Added 2021-10-27 21:25:09 +0000 UTC

Over the week-end, Mike, Marcel and I flew to a private collector that might have other items to help us with our Apollo comms restoration. The collector, who is super nice, is also very private and wishes to remain anonymous. While Mike was foraging in his many documentation shelves, he found this.

It said: support manual for the Apollo Block II Special Test Equipment PM RECEIVER. And it's from Motorola. Could it be? It is! It's the manual for our PM receiver, which is currently tuned to the wrong frequency.

Compare to the picture of the beast on the bench:

Yep, it's the same thing. Not a complete coincidence, because the PM receiver was purchased by Steve Jurvetson from this collection. We could not find the manuals for the other boxes though, but the collector believes Steve may have them.

Would the documentation indicate the correct crystal for the VCO?

Yes it does!. 23.307292 MHz. But we had figured that out already. After reading the manual, we can comfort ourselves that we had reversed engineered it mostly correctly. But of course the manual has much more details and the complete schematics. Would it by any chance tell us how to re-align the VCO after you change its crystal frequency?

It does! It has the complete procedure for the 10 or so adjustments. Our chances of getting that PM receiver retuned to the original Apollo frequency just went from tenuous to very high.

The manual was gifted to us. Marcel also found a few small items to purchase, like this North American binder:

And this mystery Z80 single board computer:

But there are other major items that the collector is willing to loan us to help us out. We need to find a way to arrange secure transportation. But this unexpected manual find was already worth the whole trip!

Now, where to find the crystal at the very unique frequency? This will probably require a special order from someone that still polishes crystals to order - not many remaining places for this once very common thing.

Marc