Quote:
Originally Posted by old_coot88
Pin 9 of the 8BU11 is fed thru a resistor (blurry print looks like it's 100 ohms, can't read the R designation). There should be 130V on the supply end of this resistor. Is there? If there is, the resistor must be open, giving you the 0V you're getting on pin 9. Does the resistor look cooked?
There's a .01 cap from pin 9 to ground (can't read the C designation). It might be shorted. Or possibly a short in the tube.
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So jumping all the way back to this. I went ahead and tested the resistor in question. It's hitting around 140V on each side. I'm not seeing any significant drop in between. I'm gonna recheck that. It's buried very deeply in and difficult to reach with the probe. But assuming that's correct, does that sound correct to you all, or does that seem unusual that there's no significant voltage drop across the resistor, even if there is continuity?
As for the .01 cap, how would I go about measuring that?
I suppose I could also sub a tube to be safe as well. I reverified that there's no voltage on pin 9, so somewhere between that resistor and pin 9, I'm losing voltage. Maybe a cold solder joint? I haven't done any soldering there as of yet, but I've heard solder joint issues are a common problem in portacolors.