Update from OP:
I replaced the MAX4016 and the 74ACT244 -- reasonably monumental achievements for me as someone who has never done any SMD work previously -- and the GPSDO is behaving exactly as it did, save for the fact that freezing or tapping the 74ACT244 no longer introduces visible glitches on the scope or prompts brief periods of outputting a working 10-MHz ref signal.
Summary: My unusual BG7TBL-style GPSDO, which worked for 6 years, recently stopped outputting a 10-MHz ref signal, even though Lady Heather notes that the RX is working nicely, time functions, too, as well as OCXO lock/control, etc. Everything but the ONLY thing I require: a 10-MHz signal to discipline my freq counter.
The end of the ref output chain looks like this: MAX4016 op-amp, which feeds a 74ACT244 distribution or gating chip, which outputs 10-MHz ref signals, one sine, one square, through separate SMA connectors (just before the connectors there are a couple of SMD caps, probably some kind of low-pass filter?).
I have a 10-MHz "almost perfect sine wave" signal on the input pin of the MAX4016, but NO output to the 74ACT244. I replaced the MAX4016, no change, but when I tapped on the 74ACT244, I could "glitch" the 10-MHz signal. I replaced the 74ACT244. No change, but now tapping does nothing, which probably indicated a bad 74ACT244?
Lady Heather suggests that the rest of the unit is working fine. I have a 10-MHz signal on the input pin of the MAX4016, and on the "shoulders" of the 1k resistors there.
Thought 1: Acquire the signal through a small capacitor and feed it through a MMIC amplifier on a small PCB and, once buffered and isolated, pass it to the input of a distribution amp through a separate BNC connector for use in downstream devices (with controlled amplitude).
Thought 2: Acquire the existing signal as above, amplify it with a MMIC, and then reintroduce it to the caps in the output network, right near the sine wave SMA output connector, thus leapfrogging the goofy parts and supplying an amplified and buffered 10-MHz signal to the output. Looks like any dc present on the amplified signal would not be "fed back" into the 74ACT244 because there's a series, dc-blocking cap inline. This method might take advantage of the small network of caps just before the SMA output connector for harmonic filtering. ??
I could also buy a new cheap GPSDO unit as discussed above, but fixing and hacking this thing is now driving me to either fix it, or fix it to death.
Any thoughts?
BTW: I don't have a schematic for this unusual unit, but I will upload a pic or two later tonight.
As always, thanks,
--TG