Kit building

[TC Chris]

Last night I built a kit device for the first time in ages (how long ago did Heathkit close up?). The was a Velleman kit from Jameco. It's a tiny Christmas tree with flashing LED lights. Two evergreen-shaped circuit boards that fit together at right angles. You stuff the circuit boards and solder away. Several resistors, 4 electrolytic caps, 4 transistors, and a bunch of colored LEDs. It sits atop a 9-volt battery and flashes away colorfully.

Built a second one, and two sets of LEDs don't flash. I verified proper polarity of caps, LEDs, and transistor orientation, so I'm guessing a part is faulty.

The temperature zoomed up from 9 deg. yesterday to 23 deg. today so instead of trouble-shooting, I drove 30 mi. west to Sleeping Bear Dunes National Lakeshore, our local national park, and went snowshoeing.

Chris Campbell

[Doug]

Dansmallparts has couple heathkits you can build

[Dr. Radio]

Heathkit said "Goodbye" in 1992.

I found an old article while surfing the web awhile ago. One major factor at that time was kit building and hands-on electronics were not the rage anymore for the younger generation---video games were.

[Dr. Radio]

Are your jumper wires soldered properly?

https://www.jameco.com/Jameco/Products/ ... 211781.pdf

[TC Chris]

Laughing... on the first one, the jumpers were an issue. Not getting them right, but trimming the ends after soldering. On one of them, I cut the jumper and not the excess wire. Then did it again on the 2nd one. Slow learner....

I was going to diagnose but got interrupted by an emergency heat call from my sister. Why is it that heat only fails on Sunday nights?

Chris Campbell

[TC Chris]

Just went out to the shop, where my electronics bench is the top of the table saw. I checked carefully for polarity on the LEDs and electrolytic caps, and for good solder joints and no accidental bridges. AOK. Then I took my little Radio Shack transistor checker to the 4 transistors. It's gt a little pot that you rotate until the light goes out, so I assume it's measuring cutoff. One of them did not match the others in terms of when the light went out so I'm wondering if I have an out-of-spec transistor. Maybe I'll see if I've got a little NPN that behaves like to other 3 on the checker and then substitute it. No idea what the specs are.

8 of the LEDs flash like they should. There's another set of : 4 are off always and 4 are on always, which is probably what happens when the two sets aren't triggering each other.

Chris Campbell