[RetroRev]

It's got the neg joined to the white and green, the pos joins up with reds on the rectifier

[RetroRev]

Excuse me not rectifier. They're hooked to the large black cap on the top side of the radio.

[radio1]

I don't see that, under the tar, does that cap connect to ground? (cap on the right)

[RetroRev]

No it does not. It connects to the white and green wires on the negative side. There's nothing under the rtv, just there holding the cap in place.    


I believe it to be c59 on the schematic

   

Sorry if the images are a bother. I'm a very visual learner.

[RetroRev]

After a little fiddling with it, adjusting a few components to make sure there were no bridged connections or anything, I now get a very very low frequency hum from the speaker, no matter what I do.

I've been poking at this thing for a good few hours, though and I think it's time to call it a night.

I am exceptionally tempted to just cut everything out and rewire the whole thing from scratch, tbh. Nothing worse than having to go through and check someone else's work. Especially when they're not around to question about it ?

[radio1]

Thought it was an axial, looks okay, I see what was done.

[RetroRev]

I think I've figured out the issue. It looks like the last person to work on this finished sections 2-4, but was about ¾ the way through 1 when they stopped for some reason. I've found a few missing resistors and a missing cap or two as well.

[MrFixr55]

Good Sleuthing RetroRev. As a kid, one of the many dumb things I did on purpose was to attempt to fix Heathkit projects that never worked when someone else built them. Sometimes, another set of eyes will solve the problem. Unfortunately, for this radio, you are the other eyes! Give yourself a pat on the back when you get this going.

BTW, if you are using a PM speaker and did not "up" the capacitance of the filters, you may get a low hum, even with the volume control down. This is because in a speaker employing a field coil, there is a "hum bucking coil" in series with the speaker voice coil. This is engineered to cancel power supply hum by being wound in "reverse polarity" (maybe not the best description but should work) to the direction of the field coil. In addition, the field coil acts as a "choke", giving resistance to the "Pulsating DC" ripple in the power supply that a plain ol' dropping resistor does not provide.

[RetroRev]

Alright yall! Time to (hopefully) resurect this thread along with this radio! I think I've finally gotten my hands on a signal generator that should work.

   

I'll be hooking it up tonight to make sure IT works first! Will check back in with the (again hopefully) positive outcome!

[RetroRev]

Alright well update time already! 

Signal generator works beautifully. I performed all the tests on page 106 of the radio museum downloadable PDF: 

   

All tests were good, but one. When I tested point B, instead of a normal level tone, it was notably quieter than the rest. 

Not sure what that says about the circuitry. 

Also, I've moved the unit to a different location with much better am/fm reception and still nothing. 

It shouldn't need an antenna hooked up to get at least static, right?

[RodB]

You should be getting the same volume when injecting a signal at point A and B. If it's a quiet tone then you may have a weak 6V6, but at least you know the audio works and can come back to it later.

You will always need an antenna to receive signals, especially FM. Use a loop of wire attached to the antenna terminal. Concentrate on the AM section first. It would be nice to be able to inject a 455 kHz IF signal at the antenna and different points in the RF stages. Barring that, maybe there's a trouble shooting section in your documents for this. Also, check the tube voltages and compare them to the voltage chart. It may give you a starting point.