PCS - Wifi board stopped and 3V3 LED fades out

[robertwa]

I had my PCS controller powered up. All looked good. Wired the minimum wiring to talk to the PCS, 7 wires on the X420 data connector. Was having difficulty getting it to go into enable mode by applying 12V to Input 1 pin, but last night was able to get it to enter drive mode by applying 12V to Input 2. Parameters were visible on the UI.

Fast forward to this morning, and now I cannot get the activity light to come on. I also see that the 3V3 pwr light will come on, but slowing fade away over a minute or so. If I toggle 12V off and back on, it brightens up for a while then fades again.

I tried recharging the 12V battery, using a power supply, removing wifi board, applying 12V and gnd direct to pin vs. through the 35 pin connector, but still the 3V3 light fades out.

Anything else I should be looking at or ideas as to what may have happened?

[robertwa]

Did a little more troubleshooting. From the schematic IC4 converts to 5V and then IC1 steps down further to 3.3V. I probed the IC output pins and it will hold 5V at IC4, but IC1 will only output 2.5V at first, dropping below 2V after a short while. I'm not an EE, but looks like something is up with the power circuit. Any ideas?
Thanks,
Rob