Working on this 46-200 and its a version where the 35Y4 has been replaced with a 35Z5, code 122. There is a cadohm resistor in this that Riders does not show. Connects between pin 2 of the 50L6 (filament) and pin 7 of the 35Z5.
Pin 7 of the 35Z5 corralates to pin 8 of the 35Y4 which would be part of the filament string. I'm measuring 83 ohms across this. Is this a good reading for this or has it drifted way out of tolerance?
Riders most often shows the original Code 121 version schematics and sometimes in later volumes any production change notes - many times not.
Let me check the Code 122 version service bulletin when I get home and I'll get back to you here...
That candohm, R100 is the same in the Code 121 schematic and in the Code 122 version schematic - didn't change. 80 ohms.
Thanks Chuck, but now I'm confused. Riders says the 46-200 is in volume 16 page 9 for Philco. That schematic has no R100 or a resistor with a value of 80 ohms. Also it shows a tube lineup of 7A8, 14A7, 14B6, 50L6, and 35Y4.
The label on my cabinet clearly states a model 46-200 codew 122 with a tube lineup of 7A8, 7B7, 7C6, 50L6, and 35Z5. The chassis is also stamped as a 46-200 code 122. So what gives?
You have a Code 122 version. Have not seen the Riders, but it sounds like it's not correct. R100 (as called out in the Philco service Bulletin PR-1135 for Code 121 and Bulletin PR-1298 for the 122) is an 80 ohm candohm unit (filament string ballast). The 46-200 Code 121 did NOT have a 14B6 in it.
The Model 48-200 has that tube lineup in the Rider's you are referring to. There also is no R100 filament string ballast resistor in the 48-200 because the IF tube has a 14 volt filament (14A7) instead of the 6.3 volt (7B7), the difference which R100 makes up.
Riders got it mixed up. There's the confusion.
Chuck, Mallorys also shows the same tube line up for the 46-200 that I have: 7A8, 7B7, 7C6, 50L6, and 35Z5. So did Mallorys copy from Riders?
Might it be possible that Philco made a mistake when they labeled this radio? Pictures of the 46-200 match mine to a tee.
Don't know about Mallory. I did some further checking and the schematic that Riders shows as the "46-200" is actually the CODE 125 version of the 46-200. My Production Changes for the Code 125 version reflect the two 14 volt tubes and omission of R100 in the fil string.
Your set, with that tube complement, is a Code 122 version. The changes from the original Code 121 are only the rectifiers and filter cap and the addition of dropping resistors R101 and R102. This permitted the use of a PM speaker. The new three section filter cap and two resistors were added because of the field coil elimination.
Chuck
Thanks Chuck. Well at least Beitmans got it right. Just downloaded the schematic.
Another question. There is a 120K resistor from pin 4 to pin 6 on the 35Z5. Pin 4 corresponds to B- and pin 6 is the same point as pin 4 of the 7A8.
According to the schematic it should be either a 47K or a 100K resistor. Is there another cgange I don't know about?