LEDControl library - turn on whole row?

I have breadboarded a tiny 2 column X 4 row LED matrix to test out the MAX7219. Everything works great except for 1 thing: I can’t turn on both LEDs in a row at the same time; doing so appears to reset the MAX7219 and put it back into power-save mode. (All LEDs go off and stay off.)

Currently I’m using the 5V output of the Arduino Uno; does it sound like I’m exceeding the capacity of the board to supply power? Should I try it with a separate 5V source?

FYI I can turn on all 4 LEDs in a column, and basically any combination as long as it’s not both LEDs on the same row.

I’m using a 560ohm resistor for RSet.

Snapshot of my setup is attached. I got the light combination shown with this code:

lc.setRow(0,0,64);
lc.setRow(0,1,128);
lc.setRow(0,2,64);
lc.setRow(0,3,128);

Here’s an example that I’m NOT able to do (turn on whole row):

lc.setRow(0,3,192);

Thanks!
John

Well it’s not an issue with the power supply. I tried it with an external 5V regulated power supply and got the same result.

I’m going to try it with a different max7219 IC.

Problem turned out to be the value of my RSet resistor. I was using a 560 ohm which was nowhere near what I needed (about 15k). I tried it with a 10k ohm which is the highest I have on hand, and it now works fine. Need to make a trip to The Shack to buy the proper 15k size.

John