Ok, so what is the safe way to test them? They happen to be the last part on my ESD mat by chance, I see its 80$ each for a replacement. I almost don't wanna do the work until I know they are OK.
Red and blue wires going to the diodes into an aluminum bar grounded by the chassis.
https://w140.com/tekwiki/wiki/Tunnel_diodesIt just says heat, so I should be careful not to break the wires. So if I try a diode test from a 34401A they can break?
edavid wrote here
https://www.eevblog.com/forum/repair/tunnel-diode-polarity/I don't see any reason why a DMM diode test function would hurt a tunnel diode, unless it were a very tiny low current device (in which case it would be useless in a pulse generator). It's more likely that 30-40 year old surplus Russian electronic parts are poorly tested/flaky/unreliable.
Given that they are power diodes on a giant heat sink, I think ESD is the only threat ? So they should remain on the mat.
So I think this is how it goes, I measured it
They are roughly reading 0.6V on the diode test. They are reversed polarity to the bus bar. I think the diodes are identical but they are reversed inside of the junction so that you can install both of them in the same way or so they sink heat properly.
One is 0.64 and the other is 0.63
I could not resist.
So it seems this is fixable. And I would not be suprized if you can put some kind of other part network to mimic that diode there because there is room in the chassis and power supply rails to spare, maybe thats wishful thinking to make a replacement diode from something.
So I think I am good to work on this since those would be the biggest traps?
I can't handle that much stress not knowing if they were shorted lol, at least I think now it has a good chance of working. Looking at the pictures it seems that there is some kind of other application for these diodes at high frequencies where they are mounted to the PCB in some kinda on board blob thing, where most of this caution comes from, this looks like pretty robust.
If the wire breaks during assembly I will crimp a ferrule with some strands of wire as padding around the tip of the diode so I don't heat it again, then again I would like to see if a faberge egg is bouncy, this thing aint that priceless !!
And at least if that test broke them, you will know what it does so you are not tempted with your own diodes to see what they read.