[Ron Ramirez]

Well,

I printed out copies of the ratio detector circuits of both the 100-T Coronet and the FM-100-C, from which the wide band ratio detctor transformer was taken.

Here is the original 100-T circuit:

[Image: http://www.philcoradio.com/images/phorum...RatDet.jpg]

and the FM-100-C:

[Image: http://www.philcoradio.com/images/phorum...RatDet.jpg]

I had my ratio detector wired as per the original 100-T circuit above, save for having the polarity of C66 reversed to accommodate the reversed diodes inside the wide band FM-100-C ratio detector transformer.

I looked over every connection...every resistor...every capacitor.

All was wired correctly.

So...

I removed the wideband ratio detector transformer and reinstalled the original 1960 transformer, also replacing the 8 uF electrolytic with another, connected as per the first diagram above, and...

I fired it up and it works great!

Reinstalling the original ratio detector transformer seems to have taken care of all of its issues. Volume seems normal now, the magic eye is responding properly, and the mysterious "double spot" tuning issue with two peaks is now gone. It tunes normally, sounds normally, and works normally. So the FM-100-C's ratio detector transformer obviously has issues, and it will find its way to the "round file" when I go back to the basement workbench shortly.

I think that I will recheck alignment on FM and AM, replace the lamps on either side of the dial, and then call this one finished. Yes, it's mono FM, but listening to my Fisher 202-R tuner on a regular basis has made me become accustomed to Living Mono FM. Nothing wrong with that.

Now to decide on which one of those miniature solid state amps to invest in, and then this Coronet will be going into the living room credenza.