Larger 7 segment with MAX7219

I'm setting something up where I'm using 7 segment LEDs for data output. I've tested some smaller red 7 segment and have worked out the Arduino code, the wiring between the Arduino, MAX7219 & the 7 segment, and it has worked fine.

For the final product, I want to use larger 2.25" tall 7 segment, but I've run into trouble. I'm 98% certain that the wiring is correct, as is the code, but the 7 segment is not illuminating at all. Here is the link to the larger LED (Jameco #97201): http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&pa=97201&productId=97201&keyCode=PDF and the one I used for the testing (Jameco #17187): http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?search_type=jamecoall&catalogId=10001&freeText=17187&langId=-1&productId=17187&storeId=10001&ddkey=http:StoreCatalogDrillDownView

They are both Common Cathode, and seem to have very similar power needs. I have a 10k resistor on the MAX7219 ISET pin, and two capacitors, (100n & 10pF) , between the ground and power, which are both supplied by the Arduino.

Does anyone more able and aware than me happen to see something obvious I'm missing?

Probably a silly question but did you re-wire for the new segments as the pinouts are different.

Good question, but yes I did.

Next silly question then. Have you tested the segment pinout, maybe they have sent the wrong version. If the answer is you have tested it then it's time to describe pin for pin how it's wired to the MAX7219 and post the code (or sample code) cut down to minimum that works with old segment but not with new.

That display is 4 LEDs in series per segment - needs more than 5V to light up. You would do better with common anode version and TPIC6B595 to sink current from a 9 to 12V source (color dependent) thru each segment.

CrossRoads: That display is 4 LEDs in series per segment - needs more than 5V to light up.

Really? Interesting, and unfortunate. The MAX7219 is so easy to use.

Would you mind telling me how you were able to determine that? Obviously I'm not as good at reading datasheets as I thought I was.

recur: Would you mind telling me how you were able to determine that? Obviously I'm not as good at reading datasheets as I thought I was.

Sadly, the datasheet is gobbledegook. Not the first time this has happened. It refers to forward voltage "per chip" which is what the catalogue page reflects, but then diagrams that there are two "chips" in series per decimal point, and four per segment proper.

Picture is right in the datasheet.

As I said, you can use a TPIC6B595 to sink current from the cathodes, the lower of the 2 parts.
MAX7219 can be used with the common cathode part, the upper one, but you need to add components.

MAX7219 high voltage App note AN1196.pdf (69 KB)

Paul__B:
It refers to forward voltage “per chip” which is what the catalogue page reflects, but then diagrams that there are two “chips” in series per decimal point, and four per segment proper.

Thanks for that. That makes sense. I’ll have to more careful when looking at these datasheets.

I’ve not encountered this before - does that mean the forward voltage and forward current is quadruple?

Only voltage - since the LEDs are in series, they all share the same 20mA.