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Hmm. Displaying 10.695 does make it sound as if the PLL's 16 MHz output isn't getting into the counter module. Not since about 1973 have I tried to troubleshoot a counter problem without a 'scope. And that counter used vacuum tubes. Did get it working, though. I did have a schemo for that...

Why is it so hard to find a good 1978 Firebird I can just use as a daily driver? Aside from how many of them were totalled by adolescent or drunk (or drunk adolescent) drivers in the last 48 years, you'll need to basically rebuild one that isn't a genuine "barn find" with low mileage. 48 years...

Good point. You wouldn't choose a 50-year old model as your first car. Especially if it would need an overhaul before you could drive it to work every day. 73

The Amphenol "86" series of plugs included the 8-pin that was identical to the base of an octal tube. Basic number was "86-CP8". The suffix numeral showed the pin count. The radio above has a 86-CP9 sticking out the rear. The mating socket was the series 78 connectors. Original catalog number...

Excellent job! Just watch for glitchy connections from top side traces to bottom side foil traces. They used small pins commonly called "griplets" soldered to foil on both sides. They have a tendency to develop fatigue cracks and cause intermittent faults. 73

Just over 30 years ago, a customer wanted a roger beep that nobody else had. Started with a "Roger K" board and hacked it to become the infamous "Bump-Bump". The CAD system we used back then under DOS was called Supercad, sold by a company called Mental Automation. They have been gone for a...

Way cool! 73

Not to put too fine a point on it, but did you verfy the PLL chip has power? Troubleshooting a dead radio should begin with an inventory of all the power supply branches and regulated voltages. A radio old enough to use zener diodes to regulate critical circuits especially. Dead zeners were a...

That connector is for the power supply. Doesn't have one built in. That was a base or mobile radio. A separate power supply was used for DC-powered mobile and another for AC use indoors.

Rock on! Gotta love it when a plan comes together. 73

Hmm. The schematic above doesn't seem to indicate R1 and R2. Which ones are they? 73

https://www.worldwidedx.com/threads/pride-dx300-basket-case-no-maybe-more-like-body-bag-case.264657/ Found it. Shows the two transformers we use. Also shows that each power supply board has to be modded to accomodate the substitute transformer. Mostly a matter of larger filter caps. 73

I did that once back in the day before I had a HV breakdown tester. The transformers were marked 660 VAC. Wired the secondaries of two of them in series, the 1320 V into a full-wave doubler got us 3700 Volts DC. For about a minute. Then the sound of an arc, a bright flash and the breaker...

I can point you to some of that stuff. See my old post about the "body bag" DX300. It's bed time. I'll check back with some specifics later. And if you want to be a guinea pig for transformer substitutes, we can work that out. 73

If you have a ham or shortwave receiver on hand, you can tune in one of the four AM/USB crystals and 'eavesdrop' on it to see if it's running. If you can hear the carrier from one of that set of four crystals, the gremlin is elsewhere. 73

I understand the rules and wish to enter the drawing. 73

You didn't mention if the meter works in SWR mode. It's common for a meter that old to become mechanically seized on the inside. If the meter is free and moves okay, I'd suspect C190, a 0.47uf 50-Volt electrolytic cap. If all the radio's electrolytic capacitors are original, this is more...

That counter can be a hair-puller when it breaks. It takes the 8 Volt regulator output and passes it through a 3-Volt zener diode to supply the 5-Volt chips. We got in the habit of taking a 3-terminal TO-220 7805T regulator and placing it face down with the input and output pins in the holes...

The meter that was used to obtain the numbers in the Heath manual would have been one of their VTVM models, most likely. Used a 1.5-Volt flashlight cell to power the Ohms scale. You need a meter that uses DC to measure resistance when comparing to the manual's numbers. Worn-out front-panel...

Our answer to the ground loop problem is to connect a .001uf disc cap from the coax shield to the circuit board ground near the synthesizer circuit. This grounds the braid for the RF circuit, and blocks any DC-ground loop issues. Very cool! Which DDS did you use? The 985x or the 5351? 73