Sunday, February 03, 2019

soldered stuff

It was Soldering Day!

Happy with the physical layout, I soldered parts to the new custom dew heater controller printed circuit board. Took a while! Did the components in the afternoon and the jumpers and leads in the evening.

Did up the Kick-Me-Not red LED blinkie tripod lights with little battery packs. Now I can use rechargeable AAA batteries.

And to the Oregon Scientific portable weather station, I hooked up an external 4xAAA battery pack. Like the OneWorld hack, no more CR2032 batteries! Previously the Oregon needed two and the OneWorld consumed one. Now I can use standard batteries. Actually, I could use rechargeables here too...

Later I shrunk the shrink-wrap on the connection points. Done!

Tested everything.

No problems with the KMN lights. After converting three pieces to use external power over 2 years ago, it was good to have these up and running again.

The Oregon beeped to life as I made the second connection. Good stuff! I don't have to feel anxious about using the backlight anymore.

But the dew heating system? My first powered test failed. It was not working correctly. Both LEDs lit but burned steady! They did not blink no matter what I did with the pots. Oh boy. What have I done...

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Oops. Found that I had installed diode D3 backwards! And I was missing a wire on net N6 from capacitor C4. Fixed. Tested. It still didn't work right. Crikey.

Thank goodness for desoldering braid.

Checked for shorts, touching wires. As much as possible, I tested components on the board. The resistors all seemed OK. The pots seemed OK and the pin outs were acting as I expected. The diodes D1 through D4 seemed OK. Couldn't get reliable readings from the transistors in their circuits. Checked for continuity on all the nets: OK.

I redid the schematic from scratch but ended up with the same result. I redid the layout in ExpressPCB: again, same result. Dang...

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