Ditch the 866As. These are hazardous material. They contain Mercury. Your hazmat recycler is the right way. Do NOT put these in the regular garbage. If you choose to use them, be sure to have the amplifier in upright operating condition and let them warm up filaments on at normal room temperature. In my basement, I used to have to put a cardboard box over the Warrior in the winter (58 degrees in the shack) and let them cook a half an hour before turning on the HV supply. Mercury Vapor Rectifiers flash over and blow the fuses and stress other parts if they are not warmed up properly. This is true for the Heathkit Warrior as well as the Johnson Valiant. When the amplifier is tipped up on its side, the mercury puddles in such a way as to cause arcs. Then you have to go through the half hour or more reconditioning to get the mercury to go back where it belongs. I hate 866s.

     If you insist on using 866 rectifiers, discard any (without bothering to test them) that the plate shows signs of flaking off the black surface, or the particles loose inside the envelope of the tube. These will eventually fall into a spot that they short or arc, and possibly destroy unobtainium components in the radio or amplifier. Charles Shultz (and Charlie Brown) have presented papers to the IEEE and American Institute of Physics (AIP) regarding the Law of Selective Gravitation, otherwise known as "The Jelly Bread Rule" to conclusively prove this theorem. Further discussion of a corollary of this theorem is at: http://en.wikipedia.org/wiki/Buttered_toast_phenomenon

     Replace 866s with (Argon filled) 3B28s if you still like the flicker of the rectifiers on the modulation. They glow a pretty purple. They are not subject to flashback arc when tipped on their side during repairs - no need to warm them up for an hour to condition them.

     Or use the solid state replacements from Surplus Sales of Nebraska. Be sure that the solid state output pin is the one connected to the capacitors. You do not want to have the current run through the filament winding of the low voltage transformer. Also, the Johnson Valiant wiring and terminal strips and low voltage transformer are subject to failure. If you use the direct plug in replacements, you can disconnect all that stuff and prevent the arcs documented in my Johnson Valiant article on this page.

Ordering information: http://www.surplussales.com/Semiconductors/Diodes-Rectifiers-1.html

Photo of solid state replacement 1N2637:

Another possible source for exact 866 replacements is RF Parts:
https://www.rfparts.com/866as-1.html
They also have larger diode packs similar to Silicon Alley's offerings, which you can configure to your needs.

K2AW Silicon Alley, if you can find them:

     I have not been able to find K2AW sales any more, but some are still available on E(vil)-Bay and other places. Make your own from diode stacks of conventional larger plastic case diodes. I suggest you use 1N5408 diodes, rated at 3 amps average rectified current, 1000 PIV each, with enough in series to operate safely in your transmitter or amplifier. Because the 866 has low forward resistance, there is less need for series resistors as described elsewhere on this page for 5V4 or 6BY5 high vacuum tubes (Johnson Valiant article). I do recommend a small amount of resistance to limit inrush current.

If you still want a single package diode, NTE also has some nice microwave oven diodes. Do not get the small ones, spend the money on the good ones.