I think those were originally Geraniums (1N270?), but you could substitute a more common 1N4148 on a switch, or even a 1N4004/4007 from a coil if you don't have any on hand.

Honestly there's no reason to use Ge -- better to use it in a kid's crystal radio set than bother with it on a switch matrix.

EDIT:

Almost forgot:

Zeners are only good for some fractions of a watt of power dissipation, so when you see them used, you'll typically see them in one of two ways:

- Directly on low current loads (<100 mW or so), with a current limiting resistor.
- To switch a bypass transistor on and off to regulate a much higher current than the Zener can handle.

You generally are not going to see a Zener off by its lonesome in a cabinet somewhere. It'll be paired up with a resistor, and maybe a transistor and possibly even a capacitor to smooth out its regulation.

If they're orange and glass, rather than black or green and glass, then odds are someone's already replaced them with 1N4148s. The 1N4148 is the generic small signal switching diode of choice -- if you buy ~1000 of them they're around a penny each.

The 1N270 that would have been original isn't even made anymore, and they're about 60-70 cents a piece on eBay in small quantities. Neither is a close equivalent, the 1N34 (and definitely save any of those you have for a kid's crystal radio project.) Since the forward voltage drop is the same, you can even use a 1N4004 or 4007 you'd use on a coil here. If you use 1N4007s, you can use 'em on any switch or coil in the pin without thinking about it, and those are 4 cents a piece for 1000 :p