[Boatanchors] Fairbanks-Morse Model 9A Help Needed

[Dennis DuVall]

Jpe,

You have the polarity correct on 69, 70 and 39.  Capacitor 39 (8 mfd)  shorted would cause your resistor (38) to burn  up as would capacitor 46 (.1 mfd).

Dennis D.  W7QHO
Glendale, CA

******************

> On Apr 4, 2015, at 5:56 PM, Joe Connor via Boatanchors <boatanchors at mailman.qth.net> wrote:
> 
> Could I prevail on you for some help with a troublesome Fairbanks-Morse Model 9A? Schematic below.
> I want to make sure I have the filter caps connected correctly. My symptom is that I'm burning up a 2.2K resistor (No. 38). I can't figure out why it's burning.
> (1) On the first filter caps (No. 69 and No. 70), am I correct that the negative leads go to the field coil and that the positive leads are tied together? That would mean that the negative lead on one of them (No. 69) goes to ground and the negative lead on the other (No. 70) goes to the center tap of the power transformer. Am I right?
> (2) On the third filter cap (No. 39), am I correct that the negative leads is grounded?
> (3) the burning resistor (No. 38), connects one filter cap (No. 39) with another (No. 70).
> http://www.nostalgiaair.org/PagesByModel/762/M0005762.pdf
> 
> Any ideas?
> As always, thank you for the help.
> 
>                          Joe Connor
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