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I just snipped this out of the SAMS for the 139XLR just to help "focus ME!".

The only 7.5v zener I see is D25 (feeding CKT TRACE #6, a 7.82 volt source) but the limiting resistor is only 68 ohms. Is this the right place or is there another I am missing?

Just trying to get "better dialed in" to the patient........

[edited to add]
I just looked at the parts layout in the SAMS.....
C101 is pretty much right next door to D25(the 7.5 v zener).
Is there any chance that D25 is heating up .... and just "baking" C101 right next to it? Have you tried to isolate/touch JUST the diode under heated conditions and see if it isn't hot too? Just thinking of possibilities....

[QUOTE="guitar_199, post: 844643, member: 18156"] I just snipped this out of the SAMS for the 139XLR just to help "focus ME!". The only 7.5v zener I see is D25 (feeding CKT TRACE #6, a 7.82 volt source) but the limiting resistor is only 68 ohms. Is this the right place or is there another I am missing? Just trying to get "better dialed in" to the patient........ [edited to add] I just looked at the parts layout in the SAMS..... C101 is pretty much right next door to D25(the 7.5 v zener). Is there any chance that D25 is heating up .... and just "baking" C101 right next to it? Have you tried to isolate/touch JUST the diode under heated conditions and see if it isn't hot too? Just thinking of possibilities.... [/QUOTE]

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