Ranger Modulation Transformer resistance

[wa3dsp]

I am restoring a Johnson Ranger and the manual spec. shows a secondary resistance 28 ohms each side of center tap. I am reading about 50 ohms on each side. The primary is suppose to be 100 ohms each side of center tap and I am reading close to that - about 95 on one side and 103 on the other.

Since both sides of the secondary read the same I am assuming there is not a problem. It just seems strange that it is almost twice the specification. A failure mode I  would expect would be that windings would be shorted and this a lower resistance. Would it ever read higher in a failed state?

Were there different modulation transformers in the Ranger series? My Ranger is very old - Cathode keying, Probably 1957 or so.

73 Doug

[ke7trp]

I have never had exact readings on any trans I have checked.  I think you nailed it, Its ok since the left and right sides are equal.   

I figured it was because of the meter used.  Are you using a VTVM or a DMM?

C

[wa3dsp]

OK thanks. The meter is a good quality DVM, actually two different ones to check it.

[KA2DZT]

The slight difference in the primary winding resistance from ct is normal.  The two halves would never be exactly the same resistance.  I'll let you try to figure why.

The big difference on the secondary resistance from the manual is not normal.  My guess is there may have been different xfmrs used in the Ranger.  Unlikely there is any failure in the windings that would cause both halves to read high.

Unless it was wound with a double run of wire and one run is open on both halves, very unlikely.

Fred