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Joined: Mar 2011
I'm working on a Philco 37-630 console radio. The radio works, with except for the shadow meter. The bulb illuminates, but the meter stays dark.
I see the meter's operation is related to the arial which currently is about a 15 foot piece of speaker wire.
Would the first step be to replace the speaker wire with a proper antenna kit and go from there?
If the meter does need to be rewound, is there anybody out there who would be willing to do this? I've seen some pretty elaborate setups, and am hoping someone would be interested in providing this service to recoup some of the cost and effort they have invested.
Any advice is greatly appreciated.
Thanks,
Doug
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City: Linn Creek, MO
Doug, When you first turn the radio on before the tubes have time to warm up, is the dark band wide or narrow? If the band is dark right from the start, the vane is probably stuck. If the dark band starts out narrow, then gets wide, the shadow meter is working. I would then try more antenna, also check the alignment. I don't think the coil is open, if it were, the radio will not work at all.
Steve
M R Radios C M Tubes
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City: Evanston, IL
The Shadow Meter depends on current draw changes (on station/off station) in the radios' front end which is reflected in the AVC voltage changes. Precise alignment with a good antenna AND ground will give the radio a chance to develop AVC at nominal design levels to make the Shadow Meter move. Many meters also can suffer from weak bias magnets which also may be a factor.
Chuck
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Thanks everyone,
I've been too busy to try much more, but the shadowmeter stays completely dark all the time. Just want to confirm that the speaker wires (antenna) are correctly connected. They are connected to posts 1 and 4 with a jumper across 2 and 3.
Does anybody know where I could pick a proper antenna kit? Looks like radio shack used to have one, but no longer stock it. Instructions on how to build one would also be appreciated.
Thanks
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City: Evanston, IL
Is the Shadow Meter lamp aligned properly to shine into the Shadow Meter?
No light - no shadow - dark screen. You would not see any shadow width chages.
See my Service Tips section on the Shadow Meter adjustments and repair.
Chuck
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Joined: Mar 2011
The lamp works fine, so I'll start working through the adjustments in your service section. Would be lying if I said this didn't make me nervous!!
Will let you know how it turns out.
Thanks
Doug