Remember the Front Array which I redesigned as Front Array Ver 3? The boards finally came. And the bad news is, I do not have some of the necessary components. They will have to wait until I can scrounge up some spare cash. In the meantime, I will populate the board with what I have.
As usual, the TR-595E calls for 0.8mm thick PCBs and for my case, I wanted them to be finished in Black.
Just like the original PCB, the front is the almost the same in terms of component placement.
It is the other side which is different. I have added variable resistor for each of the 555 circuit. The switch lets you select from either one of the two 555 circuits as CLOCK PULSE for the Top Panel PCB. After thinking much about it, this is rather unnecessary but hey, it’s there.
The top PCB is the original design from Mr. Nicholas Cuhette while mine is at the bottom. Even though this board is at version 3, it is actually my first PCB for the Front Array.
HOUSTON, WE HAVE A PROBLEM…
I always test the boards every step of the way and this is no different. Except that I went too far ahead before remembering that rule. Apparently, the board’s static LEDs did not light up when I power it up. Since I tapped the power from a set of working boards, the LEDs went dim. And then I disconnected the ver 3 board, the LEDs in the working board were OK again. Yes, this is a sign that the PCB has a short.
Testing it with a a fresh unpopulated board proved that the components are not the main suspect. Yet.
Halfway through soldering, I decided to test the board by powering it up. The static LEDs did not light up. So I took a fresh Board, which is unpopulated, and tested it with a multimeter. There is a short.
The EaglePCB did not report any problems and all the connections are correct. Then I spotted this weird grouping of traces on a single vias.
It turns out that the red trace is too close to the vias. Then I remembered I was manually re-routing some tracks before finalising it. Somehow, I missed this and eventually, when I have the cash, there will be a version 4.
But in the meantime, I have to make two cuts (yellow) on the PCB. I used an acrylic scriber and a metal ruler to do that. The first cut has to be accurate as it is between the vias and the SMD resistor. Thank goodness the copper tracks were thin. Then I would need to re-join the original link (red) between the two resistors.
ALMOST THERE…
Finally, the board is OK. All the static LEDs are working except the sequential ones. I am waiting for the variable resistors which should come sometime soon. Sometime this year…
