The PHILCO Phorum
1935 623F - Printable Version

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1935 623F - tigercat - 05-18-2020

I have a 1935 623F Philco. I built a battery eliminator for it. I want to make sure I under stand the -B and the +C together on on the schematic. I have my regulated 2.0 vdc,my 135vdc,my 67.5vdc,my plus and minus c voltage at 3 volt and 7.5 vdc.

RE: 1935 623F - Radioroslyn - 05-18-2020

Hi and welcome,
I built one years ago for a 37-33. It used newer tubes but the power requirements where the same. It's good to regulate the filament voltage so you don't have any mishaps. Used a lm 317 adj regulator and a 6.3v winding to power it. The hv isn't too critical. All your voltage sound good and even better if they are stable under load. The 19 is a pretty stout tube and can haul down a fair amount of plate current for a battery style tube.

GL

RE: 1935 623F - RodB - 05-18-2020

Hi Tigercat,

Yes,the B- and C+ are connected. The C and B voltages are referenced to common B-. The C battery is used for the grid biasing of the tubes. Grid bias is almost always a negative voltage. If you follow the negative from the C battery you'll find it's connected to control grids of the tubes.

Rod

RE: 1935 623F - tigercat - 05-18-2020

So both C+(3 volt and 7.5 volt) are connected to B-.

Thanks to you both for the info.

RE: 1935 623F - Radioroslyn - 05-18-2020

Yes that is correct. So from B- your C voltages are -3v and -7vdc. B- isn't the lowest voltage -7 is. I know it's a little confusing.

RE: 1935 623F - tigercat - 05-18-2020

Sorry about multiple post. Didn't think they were going thru. New to this game. Thanks again guys.

RE: 1935 623F - tigercat - 06-19-2020

I have an earth ground hooked up to my chassis .It appears I have .65 amp draw on my 2 volt filament circuit at 1.7 volts but my tubes are not getting warm at all. I have my 3 volt + and -,my 7.5 + and -,my 67.5 is at 64 volt and my 135 volt is at 126.5. I was wondering if those readings are good enough

RE: 1935 623F - Radioroslyn - 06-19-2020

Looks ok. Battery tubes don't get hot like ac tubes as they don't dissapate anywhere close to the same amount of energy.

RE: 1935 623F - tigercat - 07-15-2020

my battery eliminator voltages are all correct but when i turn my radio on the tubes will glow and i have static on the speaker for maybe 5 seconds and then the tubes get dimmer and dimmer till they go dark and the static stops and i still have 1.7 to 1.8 volts on all of my filaments .
on tube 19 i have 1.7 volts on my F pin;(-3.2 on both G pins;)120 volts on P pin.(all dc of course). On tube 30 driver i have 1.7 on F pin;(1.5 on G pin) and 125 on P pin;
on my I-C-6 Tube i have( 0 volts on pin G2 pin) ;126 on G1 pin; 126 on P pin;1.7 on F pin; and 64 on G 3+5 pin; on 34 IF tube i have 1.88 on f pin; 126 on P pin;
.24 on center; 62 on Sg; on tube 30 2nd,DET tube i have 1.82 on F pin;( -1.5 on P pin;) .012 on G PIN; On my 32 1st A.F. Tube i have 1.8 on F pin; 31 on Sg pin;
(103 on P pin;).
I( ) on the ones that are not what i have on my prints. Any thoughts?

RE: 1935 623F - Radioroslyn - 07-16-2020

https://philcoradio.com/library/download/service%20info/wiring%20diagrams/vol1/split/Part77-Philco%20Wiring%20Diagrams%20Vol.%201.pdf
Not sure where exactly you are measuring the filament voltage. It would seem that you may have a high resistance ground connection perhaps at the off on switch.

RE: 1935 623F - tigercat - 07-18-2020

Sorry for the late response but i have been out of town. i measured all my voltages from under side of the chassis. After all filaments go dark I still have the 1.7 to 1.8 volts on my filaments and on my dial pilot light. So to me that would clear the thought of a shorted capacitor. I figured i should have around .6 amps on the filaments circuit which I had but I will double check. I was also thinking a bad contact on the on/off switch. Thanks for your response.

RE: 1935 623F - Radioroslyn - 07-18-2020

You might want to remove a few of the tubes and measure the resistance across the to fat pins on the tube's base. Should register a low resistance (10 or 20 ohms or so).

RE: 1935 623F - tigercat - 07-18-2020

Thanks
I will check them again and log resistance for each tube and try to shine all pins and "sockets" up.