self test issues

[K7RSB]

Hi Ray:
In a previous post I mentioned having problems testing the solenoids. So to make sure there was no hardware issues I replaced the 74HC595N IC and replaced the triacs, checked all the traces, also re-flashed the mcu to version 1.8.2. Here is what happening, some stations turn on and stay on while  others will not turn at all, Then after awhile the screen goes blank.  I turn off the power and restart the self test I end up with the issues. I have pretty much given up on this project, which be relegated to my projects that never worked properly. One question I wanted to ask do I have solenoids attached all the ports for the test?
Thanks, Ross Bell K7RSB

[Ray]

The issue turns out to be caused by unreliable solder joints. Specifically, some of the microcontroller pins are not soldered well, causing it to lose control of the shift register. As a result, the shift register's output enable (OE) pin is not activated, and all ports output high, which in turn drive all solenoids active. The screen goes blank because the controller draws too much current that triggers the PTC fuse. The problem is fixed after re-soldering the joints.