BE LUCKY ON A FRIDAY EVENING (or TGIF)
So, right after I made the video for the previous post, I notice that two of the green LEDs in the scanning array is not lighting up. They are the same LEDs which had the same problem when I first soldered them a few days ago. It’s 11PM at night and I have work tomorrow…
NOTHING DOIN’ ON A SATURDAY NIGHT
I know that the 4017 IC is shot and if I keep doing this, sooner or later, the PCB is going to be worse for wear. Therefore, this would be my very last attempt. And man, I know that I am getting impatient to solve this, so I will need to keep my cool.
THAT HEARTBEAT
So note that with the affected 4017 IC removed, I can now perform another test. Using a length of wire, I connected one end to the Positive Power Supply. On the other end, I briefly touched on the green LEDs. The working ones would light up (in pairs) while the affected two did not. So there is a short and I suspect, this is the cause which disabled the 4017 IC.
The first thing that I did was to de-solder the two green LEDs and give the solder pad another round to cleaning. I also have to make sure that the vias are not filled with solder again, yeah, that’s how bad my soldering is. Ha ha.
And amazingly, the green LEDs are still working despite so much thermal abuse. Anyway, after another drop of solder flux, its time to start work. This time, the green LEDs did light up when I performed the wire test, which means there are no more shorts. If there are, the two LED would not light up.
And the whole board lit up perfectly when I soldered the spare 4017 IC!
MEANWHILE…
