My Peaberry Puts out Power --- Sort Of

By JonathanGuthrie, 25 April, 2017

I've been working on this Peaberry kit for longer than a year, now. I've been tweeting updates and stuff because there's not a lot to tell. It's taken so long because it's, by far, the most complicated tangible thing I've ever built. I've written programs that are more complicated (it's what I do for a living, after all, and people never seem to want simple programs) but those aren't tangible. Of course, I have run into problems during the construction. It's part of the nature of the beast.

Anyway, when I put the finals in and tested the output power, I got exactly nothing. I've been going over the thing since then, and I found that I hadn't soldered the final output transformer properly. A casual inspection looked okay, but I was going over the circuit more carefully, I noticed a coppery glint from two of the wires coming through the pads for T5. Under the microscope, it was clear that two of the wires came through the solder blobs, but did not make contact anywhere. Fixing that resulted in output power. A whopping 20 mW or so instead of the 5W I was hoping for. The heat sink on the final transistors got hot in transmit mode, but there was no real output power.

The thing is, the transformer they were driving had two open circuits in it, so I figure the finals are blown. I have more BS170 transistors on order, so I'll replace them and we'll see. I think I'm getting close to finishing that step of the kit assembly. After it transmits and receives, the rest of the stuff is just finishing up. So, stay tuned.