Controlling your World the Easy Way

I have a cube with 5 panels and it will not turn on. If I un-plug it and plug it back in it powers on and off.

The panels work just fine with this Wall Wart: PHIHONG PSC10A-050 5V at 2A.

Sometimes I can get the unit to power the panel but not often.

What can I do to fix this or do you have something that might work better?
Mike

I'm not entirely sure what a Panel64 is so I Googled it and found this https://forums.parallax.com/discussion/ ... p2-panel64 and in the photo I see a couple of my power supply modules. I assume those are what you are referring too.

I have no experience with those panels so I can only offer general information. As you are aware the PSU5A is a switching regulator and it has short circuit protection and other safety features. The short circuit protection is most likely the cause of your trouble. The flickering point to the current limit being the root cause of the issue.

Assuming you are driving a number of those display boards in parallel the capacitors on the boards are likely to cause the PSU5a to have trouble starting up. It ramps the output voltage quite quickly and the number of electrolytic capacitors on the displays will make the load appear to be a short during the ramp of the output voltage. This will cause the PSU5a to go into current limit which will reduce the ramp rate and the current. The reduced current will then allow the ramp rate to increase resulting in a current limit event. Rinse, repeat and therefor the flickering.

The output ramp rate can be controlled by a capacitor on the PSU5a.
The capacitor marked with the red arrow sets the ramp rate. The ramp time in milliseconds is about C*0.6/5 or about 12ms for the 100nF capacitor fitted to the board. If you solder a 1uF capacitor in parallel with one that is on the module you will increase the startup time by a factor of ten and reduce the inrush current into the capacitors by the same amount. This may solve you problem.