# How to identify pinout of 7 segment display when data for it is not available online?

I found some 1-character 7-segment LED display in my toolbox with unusual pinouts. There is one however I can't seem to figure out and I even googled the part number with no results.

The part number printed on the side of it is "MAN4840A350G82", and my camera was good enough for me to show you pictures of how the pins are arranged on each side of the display. There are no other labels.

If I can't find the pinout on google, should I just assume some generic pinout?

I want to be able to use this display in a schematic created with eagle (yes I'm using version 4.17) but I don't want to pick the wrong LED display.

How do I identify what each pin represents on this display?

• Look for similar chips using google image search. Find one, look at it's datasheet. the most important is to determine the GND connection. From there you can identify all of the pins by trial and error. Jul 21 '16 at 15:56
• ... unless it's a common anode type @Eugene Jul 21 '16 at 17:00
• This one looks quite similar to your photos csee.umbc.edu/courses/undergraduate/CMSC391/summer04/burt/… Jul 21 '16 at 18:54
• -1 for the particularly crappy pictures. Sep 19 '16 at 16:20
• @OlinLathrop, now I think that's a little harsh. Satellite photography still has a ways to go in terms of resolution.
– user98663
Sep 19 '16 at 16:25

A diode tester or a coin cell battery or a bigger battery with an appropriate resistor (1k or so). Map out every pin combination by hand. Since it's not a multiplexed display, it should be one cathode or anode to multiple of the other.

• This is the fastest and easiest way to do it (even if you did have a data sheet). Oct 19 '16 at 19:01

Apply power through pairs of pins until a segment lights up. Now just move one probe at a time until another segment lights. The pin in common between the first segment and the second is the common anode or common cathode. You should be able to tell if it's the common anode or common cathode. Then simply test all the pins (with the appropriate probe on the common connection) until you know what segments are connected to what pins.

• "apply power" is a bit imprecise - apply a current source or a high impedance supply such as a low voltage in series with a resistor. Aug 20 '16 at 17:01
• They tend to be rather standard. Find something with the same number of pins in the same places on the same-size package and it's likely to be the same pinout, even if it's a different brand.

• An appropriately limited low voltage test supply (5V, 300 Ohms, for example) and poking at pins.

Depending where it came from (ie, if it's a takeout) it could be partly dead or all-dead. Also not uncommon to have a pattern which includes features (decimal point or sign) that don't light up on some models in the line.

You can find the pinout here. I found this from the MANXXX part number, which is obsolete and a current cross-reference from Liton.

Though if it was not a standard part, probing with a 1K resistor in series with a 5V supply is fast and easy and will verify functionality.