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This is where a 'scope pays for itself. Some signal is missing from this picture. Question is which one, and why? 73

More than once I have seen a foil trace along the front edge of the front circuit board burn and cut the power to the power switch. Not a common failure, but put a meter probe on the exposed pins of the power switch. If you can't see any DC voltage there, something has overloaded that foil trace...

That power supply circuit calls for resistance between the grids and ground to serve as the shunt so you can read grid current. The exact form it takes probably isn't all that important, but you're stuck with that power supply unless you redesign it to "float" the B-minus above ground. That...

Well, yeah. It's a long list. I'd guess the MV type numbers would serve to identify them just fine. This type series diode array appeared in a great many stereo amplifiers from the 70s/80s/90s. They were molded inside plastic with a slot at one end for a mount screw. I'll see if I can find some...

Good place to start Pretty well out of my league, though. 73

Now there's a list. I'll see what I can come up with. 73

Ordered the prototype batch of pc boards from ExpressPCB today. Gonna try it in a Mark 3 once they arrive in about a week. The tiny TO-92 voltage regulator got upgraded to a TO-220 type. Yes, it's overkill, but the to-92 part was warm on the verge of hot. Figured that inside a tube-type radio...

The original part was built on a very-thin copper laminate. Odds are the diode will track the temperature of the heat-sink surface rapidly enough. 73

Any chance it was connected to a base antenna during a storm? Sounds more like a fault in the receiver's first antenna-amplifier stage than the control itself. The test we use for RF Gain controls is to turn the knob full clockwise, and then bridge the tip of a screwdriver across the center...

Got a price in mind? 73

Sounds like a classic case of "if it ain't broke". 73

Whups! Kinda lost the thought on this one. I found it yesterday. If the price above suits you I'll get it packed up to travel. 73

Cool! Got a schematic to share? 73

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Yeppers. Hua Gao lists that number. Must be somebody selling them. ICA/FatBoy has other HG transistors listed, but not that one. And folks have crossed the legs of a 2SC1969 and settled for half the wattage. 73

Um... Okay. But why? 73

I have had some of those with different names on them. One of them had no solder at all on the DIN sockets' pins. Only noticed when I punched holes in the front for 6 and 8-pin sockets. Wasn't built with a RCI socket. Came to prefer the version with echo board and noise-toy hookups on the side. 73

Not a fault I've seen. Not sure where to look for the PLL's lock detector signal on that one. Might be worth seeing what a 'scope reveals there. Tiny pulses could indicate a PLL on the edge of being unlocked, maybe? Just grasping at straws. 73

Traditional shunt resistor for a grid-current meter is connected from B-minus to ground. But that assumes that the B-minus "floats" and connects to the filament center-tap, maybe through the relay and a zener diode. This model connects the B-minus to ground, more or less. At least the...

Any chance that it thinks it's stuck in transmit? Pretty sure this is what it will do if power is applied with the mike keyed. A circuit fault that keys it for you might do this. Haven't touched a 5010 in decades. Does it have a "TX" indcator on the display like a 2510? 73