89-123 Coil DC resistance questions - Printable Version
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89-123 Coil DC resistance questions - Dion - 07-08-2019
Hi everyone! I, also, am restoring an 89-123. Fortunately I restored the cabinet first, in anticipation of a potentially brutal electronics restoration --and so far that resto has met my expectations. The speaker field coil was open (I will rewind it). The detector coil (7) is open (both windings). Hopefully I can figure out how to re-wind that.
I have questions about the DC resistance of the antenna transformer (2) and the 2nd IF xfmr (20): The print specs the antenna xfmr at 16.5 pri and 9 sec. My primary is 24 ohms (secondary matches the spec). Does that likely indicate a problem? Similarly, the print specs the primary of the 2nd IF xfmr at 69 ohms, and the secondary at 84 ohms. On mine, the primary is 99 ohms and the secondary is 117 ohms. I've read that the DC resistance isn't very telling, so maybe these values are okay? I'll appreciate any new information.
Regards,
Dion
RE: 89-123 Coil DC resistance questions - Radioroslyn - 07-08-2019
Typically when the coils a bad your looking at a resistance that is much higher than the noted value. Like X10 or X100 higher. Wouldn't worry over a few ohms.
RE: 89-123 Coil DC resistance questions - Dion - 07-08-2019
Thanks, Terry! I suspected as much, but don't have enough experience to be sure. Maybe you could indulge me by answering another question: Do you know what the gauge of wire is for the detector coil? Is it the same for primary and secondary? Is there a spec for the number of turns for each? As an alternative, can I just calculate the length of wire needed to get the specified resistance for each winding? -Dion
RE: 89-123 Coil DC resistance questions - Radioroslyn - 07-08-2019
I think that the coil info for the 89/19 is around somewhere. Ron may have the definitive answer for you. Have be told it's 38G.
GL
RE: 89-123 Coil DC resistance questions - klondike98 - 07-08-2019
Welcome to the Phorum!
RE: 89-123 Coil DC resistance questions - Dion - 07-08-2019
Thanks again, Terry, and thank you, Bob, for the welcome. -Dion