[Boatanchors] Fairbanks-Morse Model 9A Help Needed

[Al Klase]

Joe,

Comments in-line below.

If you've replaced the caps as described, and the resistor still gets 
hot, obviously there is a short to ground "downstream" from C39.

Disconnect resistor 38, and measure resistance across C39.  It should be 
infinite, less perhaps a little leakage in C39.  If not the ohm meter 
should tell the tale.  Start by pulling the 6J7 and 6C5, but it doesn't 
sound good for the coil assembly.

Good luck,
Al

Al Klase – N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/

On 4/4/2015 8:56 PM, Joe Connor via Boatanchors 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?
Correct
> 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?
Correct
> (2) On the third filter cap (No. 39), am I correct that the negative leads is grounded?
Correct
> (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
> ______________________________________________________________