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model 14 shadow meter wiring - Printable Version

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model 14 shadow meter wiring - madsowry - 10-21-2025

Hi All.  Any body know where the 2 leads that supply the coil on the shadow meter of a Philco 14 code 122 are connected.  The coil was shot on this thing so I rewound it and tested it with some batteries and it was a success.  I mounted it on the chassis and it didn't work.  Happen to look under the chassis and the black wire had been cut and pushed under another wire.  This chassis was restored by a friend and it works really well but its a little messy.  I'm not going to mess with  it cause it plays good.
  The schematic shows the shadow meter connecting to both IFs but the original red wire does not attach to the first IF.  It goes to 51, the 6.5k resistor.  I tried with alligator clips to attach both red and black to the IFs.  No good.  
  Any help would be greatly appreciated.  
  Thanks

Dick

RE: model 14 shadow meter wiring - KCMike - 10-21-2025

hello. The red wire attached to #51 resistor should be correct. It's in the same circuit as the ifs.
Make sure the black wire is connected to the primary of the 1st if transformer.
Might also make sure the red wire is connected to the second transformer if primary.
If it still won't work I hope someone will chime in with other suggestions.
Hope this helps.

RE: model 14 shadow meter wiring - madsowry - 10-22-2025

Thanks Mike.  I tried what you said and when I attached the red wire to the primary of the 2nd IF, I lost all reception. According to the scem. that should have worked.  Like I said though there is a lot of floating connections in this chassis and possibly something is misplaced.  Probably why he never hooked up the shadow meter. I'm just not going to worry about it.  Thanks again.

Dick

RE: model 14 shadow meter wiring - Bill Bacco - 10-22-2025

Looking at the attached schematic, the shadow meter (#66) should be attached to the bottoms of the 1st and 2nd IF transformer's Primary windings (#23 & #27).

Also, have you measured the resistance of the shadow meter?  I think it should be somewhere around 850 ohms.

If the resistance is correct, I would check the voltages (see attached) and possibly realigned the radio with the shadow meter in the circuit.

RE: model 14 shadow meter wiring - MrFixr55 - 10-23-2025

This is the first time I looked at a shadow meter circuit on the 14, and it is pretty weird. It appears to measure plate circuit current drawn by the RF amp, or RF and IF Amp or RF, IF and Convertor, depending on which schematic we look at, which I suppose is affected by AVC Bias.

The meter is in series between the plate circuit (B+ to transformer primary) of the IF amp and B+ of the RF Amp.

Since the radio is playing without the meter in place, someone replaced the meter with a wire connection, bypassing the meter.

For the meter to function and not cause the radio to cease operation, 3 things must occur:
1. The winding has to be in series and the bypass connection must be removed
2. The coil of the meter must be the correct resistance.
3. The meter must have no leakage to its frame, causing a short of B+ to ground.

Hope this helps.

RE: model 14 shadow meter wiring - madsowry - 10-23-2025

Thanks to all you guys.  After a few trials and studying the schematic very well, I finally wired it correctly and it is playing well and the shadow meter is working. It's not the most active I have seen but it does narrow on the only strong station I get here and goes wide when not on a station.  Thanks to all again.  Love success!!

Dick