Have you looked at the spare VQB 71's that you got?
Are they common anode as well, or are they common cathode, as the image there in µC.net says?
Yes, I have in the meantime.
It's a little bit fiddly, as the display are quite fragile without any supporting structure like a PCB.
Modern displays are a bit more sturdy due to the shorter leads.
I hooked one up with 5 V DC over a 380 Ohms resistor to the central contact, which I suspected to be the common anode.
When touching the segment lead with a grounded clip, the segment lights up nice and bright.
Doing it the other way round showed no result.
So, it has to be common anode.
Trial and error shows that half of the data sheets I found are wrong
Or (which is possible) they changed the specs over the time, keeping the part number.
Like: "What the heck? The old ones sold out. Let's do it the other way round for the lulz!"
Edit:
Since each segment is made out of two smaller segments, i guess that these are in series, and thus you have 2 times Vf as drop.
Yep, seems to be the answer. All segments are actually two LEDs.
Open questions:>What is the actual difference between VQB71 and VQB84?
Judging from the schematics, they're compatible/exchangable.
>Why are there tables stating the VQB71 to be common cathode?