Found
elsewhere on the Internet...I do not vouch for the veracity.
Quote:According to Sams there are only two changes between code 121 and 122. Code 121 uses a 3pF cap between pins 5/6 of 14AF7, and R5 is changed to 470K.
All other components remain the same.
Mike's (morzh) restoration thread is here:
http://philcoradio.com/phorum/showthread.php?tid=16902
I looked...I do not have either 48-460 service manual. I also looked in my Rider's on CD and the index only lists Code 121. So I'm afraid I can't help you.
Riders shows some set use a 50A5 audio output vs 50L6GT. A change in C19 in some sets I do not know if this is what makes them different. David
Mid year change. IIRC, the tuner on the 121 is the same as the 1946 model and the tuner on the 122 is the same as the 1949 model. They are mounted differently. Also the 121 has the antenna coil on top of the chassis and the 122 does not. So in most (if not all respects) the 121 is identical to the ‘46 and the 122 is identical to the ‘49.
It's not exactly a mid year change, the code numbers I mean. You see Philco used to design different versions of the same model chassis to accommodate whatever parts they could accumulate from the various suppliers they used. In the post war period there were a number of parts shortages, so some sets, like the Philco 46-1201, could have as many as eight different code numbers, and three or more production run versions, or the same set, swapping everything from tube lineups, to what shape speaker they used. They could swap back and forth between producing different Code numbered versions depending on what parts they could get and what they were running out of.
I have three Hippo models, one good one, and two project ones, one is more of a parts set. The first one I got has a tuned RF amplifier stage,
and uses a 7A8 octode mixer oscillator, the other two have a 14AF7 twin triode mixer-oscillator, and two IF amplifier tubes. I can't tell you what year these were built because Philco Products of Canada Ltd. used two digit model numbers like the late 1920s and early 30s sets did, rather then a model year prefix like 41-, 46-, etc. But if the Toronto plant was swapping parts around like this you can bet that the U.S plants were.
Regards
Arran
Thanks. Basically all I was trying to say is that the 48-460 code 121 is very similar to the 46-420 and the 48-460 code 122 is very similar (if not identical) to the 49-900. When I restored a 48-460 code 122 and couldn’t find the right schematic, I was able to use the schematic for the 49-900.