They might be for an older version of the 5110A. Mine has a packaged 5 MHz TXCO like the one in the early 5061A. That 5100A/5110A combo was a real show stopper when it came out. Mine still works nicely when I switch it on but it's not really practical for most purposes. It does all the frequency synthesis from about 0.01 Hz to 49.99999999 MHz by algebraic methods with no PLLs. There's a digital interface that allows computer control presumably for early work on fast frequency hopping etc,
I have a couple of functioning HP 524 series vacuum tube counters and they both have ovenised octal based vacuum mounted crystals that look like the ones in the pics. One is 100 Kc and the other 1 Mc with a vacuum tube regenerative divider to get down to 100 Kc. It has a couple of neon bulbs in a relaxation oscillator arrangement to kick start the divider when you switch it on! Morris ------------------------ I just took a quick look. I have four of these ovens, definitely marked for the HP5110A. One is partly disassembled so the crystal can be pulled. It looks very much like the one in the picture that Jeremy put up. There are two quite large mica caps mounted on a disc-shaped board along with the crystal's (two) soldered leads. That's all that goes inside the oven. The envelope definitely looks like an octal tube type, and the crystal is double-convex - you can see it edge-on, or tell by looking at your reflection from either side. The surfaces appear to be gold plated. The bulb of this one appears marked with "35" and "01" (or"10"). So, if you look up the HP51110A, you'll find a workable oscillator circuit. Ed _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.