Tuesday, December 09, 2014

debugged the circuit

Had another go after the disheartening results Sunday.

7:37 PM. Tried to sort the motor direction issue. Tested the barn door tracker control circuit without the harness. It worked. Manually switched connections on the output of the board, clockwise then counter-clockwise. It worked. That was really good news for I felt that was the trickiest part of the circuit.

But still there was no motor light. The red LED was not illuminating as the motor turned. I directly tested the LED. It worked. I must have misread it and installed it backwards. Did further debugging of the LED. Finally decided to install a new one.

With the harness, things were still not working correctly. Did more reverse checks. And at long last I found it! An interconnection to an isolated circuit! There was no circuit between pins 4 and 14... I made a new circuit and tested. Not working! Sheesh.

Wait. I did more checks from a different direction... Checked the PCB and discovered the purple wire had fallen out. That's not exactly the right way to say it. It wasn't connected. It looked like, somehow, it had desoldered. Not sure how that could happen...

9:08. Connected everything up, including the harness. Everything worked! w00t! What a relief.

Upshot of all this...

My schematic diagram was perfect. My printed circuit board diagram was perfect. I made one mistake while soldering. I was still not exactly sure what had happened with the LED... No matter. I was good.

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