Thursday, February 16, 2012

FLDs, RLDs soldered


After a training day in the "big city" yesterday and a conference call for work after that, I drove to my parents' house and, over the next three hours, soldered the LEDs for the Rear Logic Display.

The lights light.

The pattern doesn't seem to be quite what it should be, but it seems to be a result of wiring or possibly the program. I'd guess it's the wiring, since I used only some loose jumper cables and because the program is just a random test that many people using this display have used apparently without incident. All of the LEDs appear to be lighting, so I'm not concerned that I'll have to make a new board. The FLDs are fine.

If I have time this weekend, I'll work on the dome. It needs patching and sanding, and it needs a couple of holes drilled for HPs and PSIs.

August seems close. My father and I will be on our Civil War trip in the spring, and with Wisconsin weather these next six months aren't going to translate into many available working days in the unheated workshop.

But we'll get it done.

Monday, February 13, 2012

It's logical

About 9 last night, my wife texted: Where are you?

I spent a full day in my parents' basement workshop soldering Teeces' front logic displays and clipping, poking and prodding the LEDs for the rear logic display. All that's left now is the solder the rear display, all 120 LEDS (240 points ... ack).

Here is droid-building in all its elegance: Hunching over a workbench with heavy-duty nail clippers taking the flanges off the non-flangeless 3mm LEDs and then taking wire cutters and snipping the LEDs' leads short so they'll make for easier soldering on the boards. It works, even if it wouldn't pass an FDA inspection for use in medical devices.

My dad did some searching while I was at work and formed a theory that the LEDs I had purchased so cheaply from eBay might have started life in large lots meant for military or medical or other precision work that contained a single component that failed inspection. It'd be cheaper, he guessed, to throw out the whole batch rather than to test each LED. The tossed LEDs then might have been broken up into small batches for cheap sales. I don't know whether it's true, but it's at least plausible.

My father was a great help when things went wrong with the FLDs. One LED on a board stayed lit. Others flickered. He (a retired electrical engineer) talked about how he would have gone about troubleshooting such a problem. After some trials, I got the thing working. Score one for rational problem-solving!