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I have never viewed the innards of an original 5E3. If you reference the schematic, the HV CT may have been terminated at the ground point of the isolation cap:
View attachment 378373
The above picture is where it is supposed to be. Someone has used the solder point to tack on the ground wire from the AC cable. Here's a clear shot of one stock.

378383
 

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Discussion Starter · #22 · (Edited)
As I said earlier, while you're in there, best to check those Astron caps. I've had to replace many over the years as they have a propensity to start conducting DC which apart from possibly causing the fuse to blow, can cause other serious problems.
PS.... Might be a good idea to replace the cathode bypass cap on the power tubes while you're in there. I suspect it's waaayyy off spec by now and probably reading twice it's rated capacitance and possibly having an unacceptable DC leakage which in parallel with the cathode resistor, would stress the output tubes.
Question for you. Since all the tubes in a 5E3 are cathode biased am I correct that grid voltage should be dead zero or is there some wiggle room on that? On the 12AX7 I'm reading (with the tube pulled) approx +1.3 Volts which I'm assuming is NOT good and reflects a leaky coupling cap.
The other caps were either zero or the meter fluttering around .02 or .03 Volts.
 

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If it's pin 2 then yes, that's DC leakage from the coupling cap. What's it reading with the tube installed?
If you turn both volumes to "OFF" it should disappear. To find which channel coupling cap is bad, turn each volume to full separately and measure the DC voltage at the grid.
 

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Discussion Starter · #24 ·
If it's pin 2 then yes, that's DC leakage from the coupling cap. What's it reading with the tube installed?
If you turn both volumes to "OFF" it should disappear. To find which channel coupling cap is bad, turn each volume to full separately and measure the DC voltage at the grid.

Pin 2 yes, but oddly tonight I get 0 V. Doesn't matter if the tube is in or out, volumes up or down.
I guess that's a good thing?!
 
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