Quote:
Originally Posted by vortalexfan
OK So testing pins 2 and 8 of the 5U4G tube socket I'm only getting 25.5 Ohms on those pins, and not the 22,000 Ohms I should be getting.
I'm guessing that means that the issues I'm having with the excessive (4.5 Amps, 520 Watts) current draw lies there somewhere?
Or is that a sign that something else further down the line is causing that excessively low filament resistance reading on my 5U4G tube socket?
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Are you measuring 2 to ground and 8 to ground, or measuring 2 to 8 ( 2 to 8 ain't helpful)?
Either 2 or 8 should have a choke(in series with B+) or B+ line connected to it... unsolder the B+ line or choke and check 2 and or 8 to ground resistance. If the resistance is much higher than before then you have confirmed the rect and transformer are good. You'll then have to disconnect splits on the B+ line from the main line and check b+ to ground resistance till you find the point that has the short.
Most B+ shorts happen in ways that make visually identifying the issue impossible. You gotta rely on instruments, logic guided by the schematic.
It is not impossible for paper caps to dead short and for that to effect the B+... usually there is a power resistor in series that smokes out first, but not all sets are wired the same.
If I had it on my bench I could probably isolate the short in 30 min.