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A silent 1928 Philco 511
#1

Hello, 
I just joined the Philco Phorum.  as an avid antique radio enthusiast ,I have always been impressed with the quality of Philco information. Some years ago, I found a Philco 511-tabletop (circa 1928.). In addition , I have several other Philco radios as well, and ,again, have been impressed with the tech data available. But, unfortunately, it must not have been available in the late 20's---or at least I have not found it! I am retired now and have more time to work on radios.
I have spent time doing some basic cleaning,tube testing, and trouble shooting. The 511 just stares back--All the tubes checked good and the filaments are glowing. Also I seem to have all the basic voltages from the transformer,as shown on the Rider sheet. The radio remains silent.  I do note that B+ is missing-hence the silence-I have checked the voltage divider--resistances seem in tolerance---BUT missing the 70K ohm  resistor. I question the condenser pack also. On this unit, none of the transformer or condenser terminals are numbered.
Is there more complete data available?
Also--what is the LOC terminal and how is it interconnected ? An antenna and ground were connected.
Any suggestions ? 
Thank you!
#2

Welcome to the Phorum!
Icon_wave

Just to start off...have you seen the annotated schematic that is in the Philco Library?

And the Wiring Diagram from the 1928-1936 Wiring Diagram booklet also in the library?

Some of the more knowledgeable folks will likely chime in with some ideas for you.
#3

Hi Bud and Welcome,
Give this a try https://philcoradio.com/library/index.ph...chematics/ Click on 511. If #70 is missing you should be able apply an audio signal to #24 and hear the signal thru the speaker if all is well. 70 provides the hv to the 27 tube which is the detector. That's why for now the set isn't receiving, there maybe other issues. Would go through and check all of the pin 2's of the 26's to see if you have hv there. In good working order about 135v of lower the bypass cap connected to it is leaky. If 0 the coil is open and will require a rewind.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#4

Terry,
Many thanks for your suggestion. I did try that at #24, but no luck. Kept troubleshooting--ultimately found an open choke #36( 1 0f 2) in the power supply. Tested by bypassing with 2--1K resistors,in parallel=500 ohms-across the open---worked! Finally have HV (B+).  Finally able to listen. Speaker was missing,but substituted with a high impedance Crosley speaker. That "LOC" terminal was connected to the antenna input--acts as an antenna.
Radio now works!
Bud
#5

Nice information!
Thank you.

Icon_lol
#6

Don't know if I'd fool w/the LOC connection. If 35 is leaky or shorted it could burn up the primary of the ant coil. Connecting the ant to the ac line even thru a small cap is going to couple whatever electrical noise that's around to your set. Could give lots of noise and interference. When you rebuild the filter can (that's where 35 is hiding) I'd reduce the value down to .001 or .005 mf 630v you could leave it out completely.

My old model 87 has it w/a new cap in it @.005 it sparks a bit when connecting the LOC to the ant post. Same set w/a bigger p/s and audio stages.

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry




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