Help Identify This Mystery Display!

[ryanrockey]

I picked up two of these displays at a salvage store. It looks like a display of some kind. 3x7 LED with 12 pins.

I have attached a few images from all sides.

Thanks for any help with tracking down how to use these.

IMG_0417 (1).jpg (775.28 KiB) Viewed 478 times

IMG_0418 (1).jpg (609.99 KiB) Viewed 478 times

IMG_0419 (1).jpg (288.45 KiB) Viewed 478 times

[philba]

My guess is it's a simple matrix. I'd start doing continuity checks between each pair of pins. Or, you could get a 5V source with a series 330 ohm resistor and see what pairs cause what to light up.

[ryanrockey]

By series resistor: 1 330 ohm on whatever pin I test as GND or a resistor on each input pin but not on GND?

This is my first try at black box testing a component and would love some advice or links about general testing methods.

Thanks for your help.

[philba]

It doesn't matter whether you run the resistor from gnd or +5. You are just trying to make a connection that will illuminate a segment. If nothing illuminates on your first two pins, reverse the connections. It shouldn't take long to "buzz" them all out. It might help to have a mirror so you can see both the pins and the display at the same time.

[Zener]

Looks like a simple 3x7 matrix organization.