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Nope. FCC wouldn't permit it. The 8734 is the only factory-installed part. It's a partly-crippled 8719. An Expo-100 style crystal kit will work with the 8734. The advantage is that the channels are all in sequential order above 40 and below 1. Modding the PLL chip inputs throws the added...
That radio dates from the mid-1980s. If your buddy had a 1985 Ford Tempo that won't start, there's a good chance it would need more than just one little thing to make it a daily driver again. 40 years takes its toll, even if the mileage is low.
Some time around the 40-year mark, you can count...
The current drain of the radio can't be measured easily using the internal power supply. But putting your meter on the 10-Amp DC hookup and inserting it into the positive wire of an external DC supply might be informative. If the radio is drawing excess current, that alone might be causing the...
It's almost never the transformer. That component tends to be a go/no-go proposition. A "partial" fault almost never happens. The unregulated voltage you measured sounds about right. The voltage regulator is failing to hold the output steady. Question is why? An oscilloscope is a handy tool for...
The whole folklore of "known" issues is mostly relevant the first 20 years of the radio's life. When it gets to be closer to 50 years, it's best to expect multiple faults. A quick "known" fix for troubles in a radio that old is probably a vain wish. When we replace all 50 electrolytic caps in...
As Roseanne Rosannadanna would say, "It's always somethin'". A friend generously offered to powder coat a DX300 top cover. Seems appropriate for an amplifier with an asking price around a kilobuck. Just one problem The powder softens and sags when heated. It filled the upper right corner. Made...
I don't remember seeing that model sold in the USA. If that radio was built by RCI it will have a circuit board ID number that begins with the letters "EPT". It's usually printed in white screen-print ink on the component side of the main pc board. The digits that follow will identify the...
For sideband stay away from built-in drivers. Stick with as many transistors in one stage as you can afford and drive them directly from the radio. And yeah, you need bias. Sideband audio quality is unforgiving about amplifier drive level. Staying around 2/3 throttle compared to an amplifier's...
For a long time FM broadcast stations used a half-wave dipole shaped into a circle. Just how equal the pattern was around the azimuth I don't know, but to increase ERP they were stacked one above the other. Don't remember seeing more than four of them stacked that way. If you're looking for an...
Robyn SB-520. A CB AM/SSB base built only in 1978. Shares the same main circuit board with several brands and models of that year. Totally analog. No present-day sort of smarts to be found inside.
Two reasons to recommend alignment as a starting point. Adjustments drift with age, and it might...
Another short late shift. But I did get the first one of them built.
Helps to tin both the solder pads on the ProgRock and the wires connecting it to the pcb.
Turns out that when I moved the voltage regulator it's now in the way of the ProgRock's USB-C socket.
Oops. But not a show...
Back in the bad old days we used a G-C tool called the 9440. Had the 1.5 mm flat tip that was a perfect fit to the 10mm and 7mm Toko coil slugs. Just one problem. The red plastic tip would snap right off if the slug was too stiff. Upside is that it was too soft to fracture a seized or stiff...
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