Drake 2-A - some crystals don't seem to work

[Opcom]

I tried a few new crystals in the Drake 2-A receiver. These are in the general coverage slots for SWL. A couple of them don't seem to work in there and I wonder if some crystals take more power to work that this little oscillator can make, or if they ever go bad. There's no evidence they had been abused.

The oscillator looks simple and is untuned for 'aux' crystals a-b-c-and d. (e works fine, it's set to cover 11m)

Is there any reason any old crystal wouldn't work?

In case anyone wants it, the schematic is also attached as a GIF that can be edited. It's from the Bama djvu manual, but there it is in several sections and not easy to see the whole thing, so I stitched it together.

[WQ9E]

Both my 2-A and 2-B had a few ham band crystals included which didn't work either.  The oscillator circuit seems more picky than most but I have not tried to modify it since I found replacement crystals from a 2-B that a local was parting out.

[Pete, WA2CWA]

Old crystal doesn't work:
Wafer fractured
Internal contact(s) bad
Crystal cut is wrong for application.
Wrong type: fundamental vs. overtone
Ckt not designed for that particular style/type of crystal
Crystal materials have degraded

[Opcom]

Gee Pete, that is very gloomy but I can't argue those possibilities where the old stuff is concerned. I guess I have a couple stubborn ones.

I thought about the frequency stamped on the crystal not being the true freq as you say. I've seen a crystal marked 52MC that was really oscillating at 17.333. 52MC is a harmonic, made by the oscillator or following stage tripling the fundamental.

I don't have a lot of experience with crystals but I just looked up overtones - which do not seem to be the same as harmonics. Seems tricky.

It makes sense because the stamped frequency correlated to the manual's chart has not always resulted in the expected range.

It's clear that some kind of tester would be useful to identify the more sensitive crystals and set aside any broken ones for cutting open to look at, maybe fix.

The oscillator in the set might do for identifying usable crystals, and the usual tools should work to find out their true frequencies. Then the true frequency ranges will be known.

All of these crystals are below 30MC. Most are stamped in the 5-16 range.

The Drake 2-A is as simple as a triple conversion set can be, but it is fairly sensitive and I put it on a chair next to the bed so I can SWL a bit at night.

The only antenna for it is a 55FT vertical wire sloped quickly up the tower so it is noisy but after attaching a 25 FT 'ground' wire and laying it out on the floor the noise was diminished.

[Pete, WA2CWA]

Here's one simple crystal checker you can build: http://schematicwiring.com/simple-electronic-applications/crystal-tester-circuit-schematic-diagram/ You can probably hang a counter on it to determine actual oscillating frequency.