Thanks a lot !
Yes it does indeed register as a double diode when I shove it into the chinese tester : common cathode on the metal can. The two anodes on the two pins.
However what worries me is that the tester also displays a 5 ohm resistance between the two anodes ?!
That's weird... maybe it's toast...
I would get a second opinion from some other TE, in case something funny is going on with the cheap tester.
Here is what my recently acquired Peak tester says when I test two random used diodes, as a pair with common connection, I tested them both ways round with slight variation in Vf values. No leakage value given, maybe I should have added a resistor to give a fault condition. I could test some T03 double diode, but would need to locate them in the mess.
David
Second opinion I now have : I tested it with a DMM, my Fluke 11 but whatever.
It confirms what the chinese meter says, but is less ambiguous.
The resistance between the two anodes is not 4+ ohms, it's a dead short !
Which means the two diodes are in // ... which explains why the DMM measures the drop of each diode to be strictly identical, 0.453mV.
How did the chinese meter manage to measure slightly different voltage drops I don't know.... but just goes to show that basic testing with a DMM still rules !
So the diodes are good but their anodes are connected internally... so it's toast. So.... now I know it's hopeless, I can crack it open and have a look inside the can !