[IamZoot]

Anyone know what the Voice Coil resistance should be?  One source I have says 8 ohms.  Mine measures much lower.  I suspect that it is shorted.

[MrFixr55]

Hang on Zoot, I am looking and will post for you. Often, they are quite low on the older radios. I will find out for you. In the Philco Library, there is a listing of speaker part numbers and the radio models they are used in. The voice coil and field resistances (or impedances, which are different) are listed.

When checking resistance of the voice coil, it is important to ensure that the output transformer secondary is disconnected from the voice coil. Otherwise you are going to get half the correct resistance reading or even lower.

[MrFixr55]

Hi Zoot, 

The voice coil for the 5" speaker used in the Model 45 should have a voice coil impedance of 1 Ohm and a field coil resistance of 1140 Ohm.

The info can be found in the Philco Library under Parts -> Speakers.

Below is a snip of the chart showing the speaker info for the 45C:
   

Hope this helps.

[IamZoot]

Yes it does tend to confirm my readings.  I am just not used to speaker impedance being 1 ohm.  I have a fairly good multimeter but reading 1 ohm tends to make you think when most speakers have much higher impedances.

I thank you for the input.  Now I have to search for other problems.