Philco 16 Code 121 Control Grid Voltages? - Printable Version
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Philco 16 Code 121 Control Grid Voltages? - NV3G - 11-28-2010
I am working on a Philco Model 16 that has been butchered by a previous repairman. The schematic is difficult to read. What are the resistances of Resistor 81? The best I can read is from left to right, 20, 100, and 130.
Also, are the Control Grid voltages correct for the Output tubes ( two 24's ) 34 volts, the Driver tube ( 24 ) 0.6 volt and the 1st A.F tube ( 77 ) 0.4 volts?
Thank you,
nv3g
Oscar
Re: Philco 16 Control Grid Voltages? - Ron Ramirez - 11-28-2010
Which version 16 are you working on, Oscar? Code 121, 122 or 123 (5-band), or Code 125, 126 or 127 (4-band)?
Re: Philco 16 Control Grid Voltages? - NV3G - 11-28-2010
Sorry. I am working on a Philco Model 16 Code 121. I would expect the bias voltages on the control grids to be negative voltages. I am measuring the voltages from the control grids to chassis ground. The schematic was a little fuzzy and hard to read. I was trying to confirm if I had the resistor 81 resistances correct and if the voltages in the voltage chart were correct.
Thanks for your help.
nv3g
Oscar
Re: Philco 16 Code 121 Control Grid Voltages? - Radioroslyn - 11-29-2010
Looks like #81 is a 250 ohm resistor with two taps. The first at 20 ohms(from ground) and the second at 120 ohms.
Terry
Re: Philco 16 Code 121 Control Grid Voltages? - NV3G - 11-29-2010
Thank you, Terry. That is what I thought trying to read a blurry schematic. I wonder about the control grid voltages, which are positive in the voltage table. I thought they were negative coming from the negative power supply source. I am looking at the voltage table ( tube socket data ) on the schematic page.
Appreciate the input.
Best Wishes
nv3g
Oscar
Re: Philco 16 Code 121 Control Grid Voltages are negative. - NV3G - 12-03-2010
The control grid voltages are negative. I am reconstructing the negative bias circuit in the Philco 16 Model 121 radio.
The previous repair person tried to do a make shift repair rather than do it correctly.
Thanks for your help.
nv3g
Oscar