10-18-2015, 04:07 PM
Hi,
I am very close to completing a restoration on my Philco 610B radio, but as I finalize things I have been looking over some service bulletin information and comparing notes from various forums, etc. It has raised a couple of questions on which I'd be interested in opinions.
One document I have from Philco is titled "Philco, 1936 Changes in models Since Publications of Each Service Bulletin." It is copyrighted as 1936 but no other specific date. It contains the various Philco radios and includes this about the Model 610:
"Beginning with Run No. 15, the oscillator circuit was changed to improve the oscillator action at 6.0 M.C. Resistors (17) (51000 ohm) and (18) (25,000 ohm) were removed. A resistor (32,000 ohms), Part No. 33-332133 was added from the switch terminal side of the condensor (7) to ground. A 20 ohm resistor, Part No. 33-020133 was connected between the 6A7 cathode and ground."
Now all the schematics I have found still show those resistors 17 & 18 (though one varies from 51,000 to 50,000 on one) except for a posting I found on the Antique Radio Forum where one person noted they were missing from his own radio.
I'd like to make the circuits work optimally and wondered whether I should follow this recommendation since I cannot find any other information regarding their removal. I can try it without them connected, but wondered also if there is in fact a schematic to support their removal?
Supposedly the runs were stamped on the chassis, but all I could find on mine were two numbers stamped in ink: an "812" and what looks like a "62". Chassis number (if it helps) on the radio is stamped as A96226.
Thanks for clarifying and recommendations in advance.
Jim
I am very close to completing a restoration on my Philco 610B radio, but as I finalize things I have been looking over some service bulletin information and comparing notes from various forums, etc. It has raised a couple of questions on which I'd be interested in opinions.
One document I have from Philco is titled "Philco, 1936 Changes in models Since Publications of Each Service Bulletin." It is copyrighted as 1936 but no other specific date. It contains the various Philco radios and includes this about the Model 610:
"Beginning with Run No. 15, the oscillator circuit was changed to improve the oscillator action at 6.0 M.C. Resistors (17) (51000 ohm) and (18) (25,000 ohm) were removed. A resistor (32,000 ohms), Part No. 33-332133 was added from the switch terminal side of the condensor (7) to ground. A 20 ohm resistor, Part No. 33-020133 was connected between the 6A7 cathode and ground."
Now all the schematics I have found still show those resistors 17 & 18 (though one varies from 51,000 to 50,000 on one) except for a posting I found on the Antique Radio Forum where one person noted they were missing from his own radio.
I'd like to make the circuits work optimally and wondered whether I should follow this recommendation since I cannot find any other information regarding their removal. I can try it without them connected, but wondered also if there is in fact a schematic to support their removal?
Supposedly the runs were stamped on the chassis, but all I could find on mine were two numbers stamped in ink: an "812" and what looks like a "62". Chassis number (if it helps) on the radio is stamped as A96226.
Thanks for clarifying and recommendations in advance.
Jim
