Hi all. On the dot matrix, all the columns work on the test game diagnostics. (as the line sweeps left to right) But the bottom row doesnt light (when sweeping top to bottom). resulting in some of the dots working, some of the time during game play.
The rows are feed from a HV5222PJ chip. Ive checked and its getting 13 volts on the VCC pin. Ive also check the resistor values are okay between the chip and the rows of the display.
What should I check next? I'm wondering if the chip if damaged or the angled pin going directly into the display.
Or could it be earlier in the data chain? There is a 14 pin Motorola chip connected to the HV5222PJ.
I could check between the angled pin of the display and ground with my cheapy hand held oscilloscope? and compare it to the other row pins that are working?
and advice would be amazing.