In this third installment of Salvaging old CB’s for QRP Parts, we’re taking a slightly different turn. I still have another CB to tear into for the next post, but for this one, we’re changing it up a bit. Pictured below is a Mystery Box Thing that I purchased at a garage sale. It was marked $3, but I think I got it for $1 or maybe $2. I didn’t know what it was, but it had a meter movement on it and PL259 connectors on the back, so I figured I couldn’t go too wrong.
It seemed clear from the outset that it was for CB radios, and I could kind of see some tubes through the grated case. Plus, the “filament” and “load” were obvious indicators that some tubes were involved.
After I got it home, a Google search confirmed that this “D&A Manufacturing Co.” made CB linear amplifiers, and this “Scorpion” model was one of them. Further research says these things were made around 1969. Given its age, the fact that it’s an amp for CB (which isn’t exactly legal) and that powering it up would likely start a fire, I decided to do as I do: I tore it apart.
Since I didn’t intend to ever put this back into use as an amplifier, I started by removing the case cover and inspecting the amplifier. I was interested to find components on both sides of the main tray “shelf” as it were. Some of the holes for wires had grommets, others didn’t. What did become clear is that this was a nice piece of equipment at some point, and so my basic tenets must hold true:
- Disassemble in a logical order
- Don’t break anything out of impatience
- Be patient (see #2)
- Save all the parts
- Look for value in unexpected areas
- Respect quality
I began by removing the tubes and anything that would unscrew or unbolt. In a short time, both my bench and my hands were filthy! This thing was a mess! I saved many of the parts but some were destined for the round file, unfortunately. That transformer was my main concern, and after removing it, I discarded it.
I of course kept the germanium diode, some of the capacitors and resistors (not pictured) and an Ohmite choke that just looks neat, if nothing else. There was also the meter movement, air variable trim capacitor, fuse holder, PL259 connectors and some great old switches. That heat sink goes with the case too, so it stays. Speaking of the case…
Like I said, the case was filthy. The holes you see in the grating are from having to drill out a bunch of pop rivets. The PL259’s and other parts were also held in with pop rivets. Thankfully, those were easy to remove with a drill. Next, it was time to give that case a wash:
Next, it got a dunk in the sink with huge amounts of dish soap and a good scrubbing. To the left is the before, and right, after. You can see that it cleaned up fairly well. But, the 50 year old paint could use redoing. When it comes time to use this case for a project, I’ll be either removing the dog ears or straightening them, and then stripping the paint and repainting the case.
I think it’ll make a great case for the upcoming Easy BITX from Inkits. Watch this blog for more information about that coming up. Thanks for reading, and be sure to let me think in the comments below. 73!
One More Thing
In case you’re wondering what that soldering kit is that I used to hold up the amp for the pictures, it’s This Thing: The Plusivo 60W soldering iron kit. My old ebay soldering iron is starting to wear out in one particular spot, and this is actually nicer and includes a ton of accessories for less than $15. I couldn’t pass it up!
Want to read more? Continue to Part Four.