[R3Sons]

On K2, pins 1&2 are shorted. On K4, Pins 1&3 are shorted. Others are OK.
The voltages are the same except #4. I must have had the lead on the wrong pin. #4 is 0v.
#1891 is a bulb. There is one wire from the volume pot to the lamp. That wire is 12.2v.
I've been testing with chassis as ground.
Point 19 is definitely 12v. I must have messed something up before. All points except #4 are the same.
X3 and X6 are bad. X2 and X4 are good. X5 I haven't been able to test yet.

[morzh]

On K2, pins 1&2 are shorted. On K4, Pins 1&3 are shorted. Others are OK. - your 0.047 caps are fried in both

The voltages are the same except #4. I must have had the lead on the wrong pin. #4 is 0v. -  better

#1891 is a bulb. There is one wire from the volume pot to the lamp. That wire is 12.2v.  - OK, so it is just 12V to lamp. no effect on the rest of the circuitry.

I've been testing with chassis as ground.

Point 19 is definitely 12v. I must have messed something up before. All points except #4 are the same. - Like I said, it is wrong on many levels, and there are probably short and burns of parts.

X3 and X6 are bad. X2 and X4 are good. X5 I haven't been able to test yet. - It seems this radio had some major surge. Caps shorted, transistors burnt. Or someone tried to plug it into something that it shouldn't been plugged into. I am not sure what those K assemblies are. If they are potted circuits, you will need to somehow replace them. If resistors are good inside, you could try to hook up bad parts (caps) outside.


If you want to be a good sport and keep doing it, great. But it seems like you might have to replace half the parts.
Basically, from what I think might've happened to it, you need to check every single component.

If you do this, we could answer questions one by one as you go along.

PS. To my taste (and had I had that radio in front of me and all the parts available, I probably could fix it in a day or so), to me personally it would not be worth it and I would just toss it. If it has any special significance....sure.

[R3Sons]

Thank you. I have to take a break from it for about a week. I'll have to do some thinking. I was toying with the idea of making a PCB and populating it with available parts. Just not sure how I would connect the tuning circuit. I could remake the potted circuits, but I'm not sure I feel like it. I was thinking about maybe just trying to connect some good caps on the outside. Like I said, I'll have to decide. Parts are very hard to find. If I had all of the parts, I wouldn't hesitate to rebuild the whole thing, but that's not the case. Thanks for all the help. I'll let you know.

[R3Sons]

Alrighty. I'm back. I'm not ready to give up. Suggestions on where to start?

[morzh]

See above.

Try to see about the shorted caps etc, remove the transistors, and do not populate them until you rectify the sub-assemblies situation. Make sure all caps are good, diodes etc. Resistors, of course.
Then you can proceed with the transistors, one-by-one, from the RF X1-X3(see if you could get the voltages more or less within the reasonable distance from those listed), and then to the audio and the audio-power ones, X4-X5, and only then X6.

Do not plug-unplug the speaker while hot. And when working with the X6 in-circuit, it is better if the speaker IS plugged in.

[R3Sons]

Thank you. I have one board completely de-populated. Just looking for the correct values. I'll let you know. Still having a bear of a time trying to find replacement germanium transistors.

[morzh]

If the small signal ones, take any Ge transistor with unity gain good enough and Vce max 30 or so V.
For the output....you could try whatever it is electrically good enough to verify radio's functionality and then dedicate your efforts to finding the proper replacement. They pop up on eBay.
Also, you could possibly look into some Russian or Eastern European old transistors, they do exist on eBay. Gosh knows, they might be physically compatible with your heatsink.

Like this one, is a 20V Hi-F (90MHz) PNP, small signal.
https://www.ebay.com/itm/185356831583?_s...R5jv4eqnZQ

From memory (I do not know if they would fit physically) the Ge output transistors are:
P201
P214
P215

Large power

P210
https://www.ebay.com/itm/355761097918?_s...R5i8qeunZQ

Not a very good transistor as the unity gain Frequency is low.



P214, a good transistor.

https://www.ebay.com/itm/283924385059?_s...R6jfsOunZQ

So is P215.



P201 not as good but likely would do.
https://www.ebay.com/itm/283888198612?_s...R7qc2uunZQ

[morzh]

https://manuals.plus/m/a0e441e8a2d89c9a9...d7b0c9_pdf

This is the replacement guide for transistors by GE parts.

So, GE-3 is your power replacement for AR14

https://www.ebay.com/itm/204894362450

Just as an example: you probably could find cheaper ones.
AR103-105 are GE-1. Again, look for more.

https://www.ebay.com/itm/226561807385?_s...R-iog-6nZQ

AR107-108 are GE-10.

Can't find on eBay

[R3Sons]

Thank you very much. I'll let you know how it goes.

[462ron]

Your output transistor X6 cross references to a GE-3 transistor and I’ve used that before. There are a few here on eBay…

https://www.ebay.com/sch/i.html?_nkw=GE-...m570.l1313  

Ron

[morzh]

Ron

yes, that was found. The problem is trying to find GE-10 for AR107/108.
I could not find even mentioning of it.
I could possibly identify Soviet NPN Ge ones, like MP10 or MP11.
https://www.ebay.com/itm/256801231393?_s...R_be5KWoZQ


I am surprised I have not found the original or the GE-10 datasheet, or eBay offer.

[462ron]

Mike, according to my ECG replacement guide, the AR107 & AR108 both cross reference to a ECG 123A as does a GE-10. These are NPN silicon transistors, not germanium. Looking at the schematic for this radio, emitter-base is around .6v for both AR107 and AR108.  The output xistor is germanium. 

Ron

[morzh]

Then it is even easier.
Yep, my GE guide also says "Silicon".