Finishing a QRP Guys Para40Set

Salvaging old CB’s for QRP Parts: Part 3

Salvaging old CB’s for QRP Parts: Part 2

Welcome to the second installment of “Salvaging old CB’s for QRP Parts”! In part 1 of this series, we described how we found a bin of CB radios and accessories at an estate sale some time back. The first radio we salvaged for parts was a Pace CB 145. The radio was disassembled to see what could be used for QRP, and found some great parts.

One thing I am particularly glad that I saved from that radio was the one I was least jazzed about: all of the random wires! I’ve already been able to put them to good use in a project to help a friend with some LED lighting. I’ll bet the engineers at Pace never thought their wiring would go into projects using technologies that didn’t even exist 45 or 50 years ago! But that’s part of the fun, isn’t it?

Let’s dig in and see what gems await us in this next teardown!

One Down, Two to Go

With the first CB teardown out of the way, it’s time to do the next. This CB is a Johnson Messenger 123A. It too is a high quality radio from the mid 1970’s. Check out this ad from 1975:

Note the MSRP: $159. That’s about $750 in 2020, when adjusted for inflation. That’s a lot of money. Is it a lot of radio? At first glance, I thought not. When you look at the radio, you find that the microphone is hard wired rather than being the typical 4 pin connector. But, there’s a reason for that, as I found.

The Method

As usual, I have a few things in mind when tearing down any device. I mentioned them in Part 1, and I’ll reiterate them here:

  1. Disassemble in a logical order
  2. Don’t break anything out of impatience
  3. Be patient (see #2)
  4. Save all the parts
  5. Look for value in unexpected areas
  6. Respect quality

The Teardown

Rather than write long paragraphs about taking it apart, check out each image below and its narrative caption.

The schematic is fully detailed, and once you start examining the board and the schematic together, it’s easy to see here the various parts of the radio are. In fact, I’m fairly certain that the entire final amplifier section could be cut away from the rest of the board and be used as-is. And, much like the radio in the last post, this rig is full of parts that can be reused for QRP projects. Such as these awesome little original germanium diodes, which new can cost anywhere from 50 cents to $1.50 each:

Removing these meant warming up 50 years of truck guck. Yuck.

One Last Thing

As I mention in the column to the right, I use Amazon Affiliates to get a little back from my blog so I can keep this QRP stuff going- it’s TONS of fun but takes lots of time! You know what saves me tons of time, though? So much that I would be completely lost otherwise? These little Hakko Cutters shown below. Do yourself a favor and buy a pair. Seriously. They’re ridiculously good and super cheap. Or, buy the Three Pack and help out your ham buddies. They’ll love you forever. If you ever get to see them in person again, anyway!

In Conclusion

Tearing down old stuff is fun, and I hope you’ll give it a try. There’s more coming, and if you found this post interesting, then make sure to subscribe to the blog in the upper right hand corner of the website.

Thanks for reading, and 73!

But Wait- What about the Microphone?

Hey, you remembered! Examining the schematic, it looks like the microphone is a crystal type rather than an electret or dynamic microphone. This surely added to the high price tag of this radio. If the owner were to lose the mic, it would cost quite a bit to replace it, and plugging in the wrong kind of microphone to this radio, would likely not have worked without modification. I suspect that the engineers left it hard wired to save the company, and the customers, some trouble down the road. What do you think?

Continue to Part 3: The old CB Amp

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