I have an old portable, 8-BJT AM/FM radio, and I started to try mapping it's circuit into LTspice. I don't really know much about radio's, but I'd guess it's a pretty common American style super-het receiver. What an ugly solder job on it too, way too much solder, and even tho it's probably from the 1970's, it doesn't even use nice low temp solder like 60/40.

It has 7 color coded RF cans. The ferrites are color coded, only 2 cans are painted, I don't see any numbers or labels on the cans. How standard are they by color ? I have an LCR meter, but I'd have to take them apart to really know what I'm reading, since they can have an LCR network inside.

 

Yes, you would probably have to take them apart and analyze the internal components, or you could place them in oscillators and see at which frequency they oscillate or use a grid dip meter to find their resonant frequencies. I have taken apart many consumer receivers of different types and from memory I have never encountered a color coded IF can or local oscillator can.

And American consumer AM/FM radio from those days would usually have IF stages at 455 kHz and 10.7 MHz. The AM local oscillator would be 455 kHz above the receive frequency and the FM local oscillator if memory serves, is 10.7 MHz above the received frequency.

 

Hello,

TOKO and MURATA are well known brands for coils.
Here is a list of TOKO coils:





Perhaps the numbers can be found for datasheets.

Bertus

 

It has 7 color coded RF cans. The ferrites are color coded, only 2 cans are painted, I don't see any numbers or labels on the cans. How standard are they by color ? I

I do remember, circa 1970, those coils having ferrite cores and they were the same colour for the same function but I don't remember which colours were which function.

 

Hello,

Have a look at these pages:
http://www.auldies.euweb.cz/me/Ame2.htmlhttps://www.qsl.net/yo5ofh/doc/if_cans/if_cans.htm
Bertus

 

Ok I have a simpler radio I can compare with, it was a kit and I think the schematic had the can details. This was just for fun, if I can't figure it out no big deal.