Recent content by nomadradio

Or a monday morning radio. 73

Martin was the genius of "insourcing". When a supplier closed, he would tool up to make a part in-house. In an age when outsourcing the manufacture of every part you use is the dominant style, it made him stand out. I'll miss them as a source of parts. Just the same, it's like adopting a dog...

The service manual posted at cbtricks.org says it's a "DR202AL" display. Didn't get any joy out of that number. Schematic shows that it's a common-anode part. I'll see if there is any kind of cross reference on the air-gapped machine at work tomorrow. 73

I remember one old timer. He'd key up and yell " 'Nother Watt, 'nother mile!" 73

We used the center pole of the relay to interrupt the screen-voltage supply to pin 4 on the big tube in receive mode. The setups that switch the grid bias higher for receive, lower for transmit just don't seem to be as stable. At least shutting down the screen grid does a decisive job of...

C92 is a decoupling capacitor. A "filter" for audio noises that appear riding piggyback on the DC power that feeds the mike circuits. We found that turning down the carrier on this radio would cause a feedback squeal on AM modulation. Boosting the size of C92 stopped it. Gotta figure other...

Makes it sound more like your short circuit is passing through the switch. Time to take a meter set for continuity with one lead clipped to ground, and poke lugs on the meter with the other probe ne by one. Rotate the selector while checking each lug. A spot that shows the short no matter...

MFJ makes a booster that regulates DC power to a radio, but this one is only good to 25 Amps. https://mfjenterprises.com/products/mfj-4418 73

Have a VERY close look at that switch. Odds are it's built from wafers of brown bakelite plastic. If you saw where on the switch the arc came from, get a bright light onto that section and see if a black bridge has burned/formed between adjacent contacts. This happens a lot in other radios, but...

Like the guy who fell into the outhouse and came up wrapped in tissue? I'll guess this is a "test" you didn't repeat on purpose. 73

Hmmm. My ancient Kenwood TS-50 uses two 2SC2879 for the final stage, delivers 100 Watt peaks. Original 30 year-old Toshibas still do the job. The incentive for the amp builder is to promise as many Watts per transistor as he possibly can. Numbers are what sell. An otherwise "wise" consumer...

I bought a complete 1 mA version of this same meter on fleabay, and it had this piece on it. The shelf where it lived got reshuffled a few months back, and now I've lost track of it. Snapping that one off to get scanned would be the easy way. Just gotta find the bloody thing. Thank you for the...

The preamp built into a lot of linears is poorly protected from the radio's transmit energy. Best way to "poof" the receiver preamp in your Palomar, Varmint or such is to flip the SSB switch. When you key the mike in AM, the radio's carrier will cause the linear's relay to switch over quickly...

Yeah, life was a lot more entertaining when there were no antibiotics and you could die from a bacterial bug. And before there were vaccines for fatal childhood diseases families had more kids, just so enough of them would survive to support the old folks decades down the line. High death rates...

The CPI radio was a good idea. Not enough of them were made to get the designs past the "field test" stage. Tweaks were necessary to achieve proper performance, best I remember. The Stoner radios had the same sorts of issue, a good idea not fully developed. Radios built and sold in the hundreds...