I found the issue with mine. All it did was blink at 1hz which the chip is designed to do when there is a fault anywhere in the circuit. Finally figured it out! It's most likely C18. There was a short between + and - at the input for the battery. I figured it out by basically desoldering every chip seeing if the short goes away or not. All chips seemed to work. So I went thru every capacitor around the chips and found C18 was my culprit. The short went away after removing it. I have my next issue of finding the value. It was in parallel with 2 other caps. One being smaller. This is my first real troubleshooting project and glad that I can tell you it's the mainboard.