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This is a really weird problem!

I hate to seem a "pain"... but if that 150 ohm resistor was shorted I would think that it would be the ZENER complaining.... not the capacitor.   The cap is a 35 volter... and we are only talking about 13.8 vdc here.   That resistor however... acts as a current limiter for the zener.   Once that zener hits the knee it will try to pass whatever current it's supply will feed to it.   If too much current.... "pop goes the diode!".

Another way to approach this might be..... measure that 150 ohm resistor...then put it back in the circuit, then measure the voltage across it. THAT will tell you how much current is being pulled. From there... you could pull one leg of the zener, one leg of the cap, one leg of a NUMBER of those parts.... and see which one is actually pulling the current.   The current draw will go away when the "culprit" is found.

Again.... just throwing out "thoughts and ideas" as they occur!!!!!
Bob

[edited to add]
one more dumb idea just happened......
disconnect one end of the 150 ohm resistor(so that the supply is cut off) and measure the voltage on the zener/capacitor.   It might sound goofy... but if something out on the board is shorted... maybe it is "back feeding" voltage from a spot and there is no current limiting (due to the short) to keep excess current from coming in and heating something up!

<blockquote data-quote="guitar_199" data-source="post: 844642" data-attributes="member: 18156">This is a really weird problem!I hate to seem a &quot;pain&quot;... but if that 150 ohm resistor was shorted I would think that it would be the ZENER complaining.... not the capacitor.&nbsp;&nbsp; The cap is a 35 volter... and we are only talking about 13.8 vdc here.&nbsp;&nbsp; That resistor however... acts as a current limiter for the zener.&nbsp;&nbsp; Once that zener hits the knee it will try to pass whatever current it&#039;s supply will feed to it.&nbsp;&nbsp; If too much current.... &quot;pop goes the diode!&quot;.Another way to approach this might be..... measure that 150 ohm resistor...then put it back in the circuit, then measure the voltage across it.&nbsp; THAT will tell you how much current is being pulled.&nbsp; From there... you could pull one leg of the zener, one leg of the cap,&nbsp; &nbsp; one leg of a NUMBER of those parts.... and see which one is actually pulling the current.&nbsp;&nbsp; The current draw will go away when the &quot;culprit&quot; is found.Again.... just throwing out &quot;thoughts and ideas&quot; as they occur!!!!!Bob[edited to add]one more dumb idea just happened......disconnect one end of the 150 ohm resistor(so that the supply is cut off) and measure the voltage on the zener/capacitor.&nbsp;&nbsp; It might sound goofy... but if something out on the board is shorted... maybe it is &quot;back feeding&quot; voltage from a spot and there is no current limiting (due to the short) to keep excess current from coming in and heating something up!</blockquote>

[QUOTE="guitar_199, post: 844642, member: 18156"] This is a really weird problem! I hate to seem a "pain"... but if that 150 ohm resistor was shorted I would think that it would be the ZENER complaining.... not the capacitor. The cap is a 35 volter... and we are only talking about 13.8 vdc here. That resistor however... acts as a current limiter for the zener. Once that zener hits the knee it will try to pass whatever current it's supply will feed to it. If too much current.... "pop goes the diode!". Another way to approach this might be..... measure that 150 ohm resistor...then put it back in the circuit, then measure the voltage across it. THAT will tell you how much current is being pulled. From there... you could pull one leg of the zener, one leg of the cap, one leg of a NUMBER of those parts.... and see which one is actually pulling the current. The current draw will go away when the "culprit" is found. Again.... just throwing out "thoughts and ideas" as they occur!!!!! Bob [edited to add] one more dumb idea just happened...... disconnect one end of the 150 ohm resistor(so that the supply is cut off) and measure the voltage on the zener/capacitor. It might sound goofy... but if something out on the board is shorted... maybe it is "back feeding" voltage from a spot and there is no current limiting (due to the short) to keep excess current from coming in and heating something up! [/QUOTE]

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