Hello there, first time post here. I hope I’m posting under the right category.
I am trying to troubleshoot a guitar pedal board which has got a Rock2 SoM module (its based on the Rockchip RK328). The unit shuts down on start up. It has got a ‘soft latching power switch’. I have two identical faulty boards same symptoms. I’m working on one board removing and re-soldering components trying to troubleshoot. I just need one working board.
There is a Mosfet used to turn on the power to the whole board. I have bypassed this and I am powering the board directly from a 12V supply. Pressing the ON button initialises the start up process just like before but instead of turning off the voltages remains. I have checked all the DC/DC converter ICs outputs and LDOs. Everything seems to be in working order.
Potential issue:
I think I have zeroed in on the problem. I could be way off, but definitely something interesting. The ACT8846 chip is used as the power management IC for the module. Here’s what I noticed
There is 5V at the INL1, INL2, INL3 pins and I measured 0.3V at OUT9 and 0V at OUT8. Why I measured those first were because ‘VCCIO_PMU’ is used for the reset IC - U2207.
I have tried manually resetting the IC described on the page 31 on the data-sheet, but this was before I had the main supply latched.
I was hoping that someone could give me further advice on what to troubleshoot and what to look for? I am aware that the microprocessor could be bricked as well, any idea how to ‘un-brick’ it?
Thanks in advance for the help.
schematic: