DC on pots question

[mresistor]

I was reading through Hoffman's guide to servicing Fender amps and upon reading the DC on pots section I have a question. How much DC voltage is considered unacceptable. Any voltage level of DC?or is there a
tolerance?  I have seen .002 vdc on some fender pots and the amp sounds great with no real issues.  Should I be concerned with replacing the offending capacitor? or is this acceptable?
Does a film capacitor block 100% of dc?


I found this information which seems to indicate a very slightly leaking cap may not inhibit the circuit operation depending on where and how it is being used. Tone circuit caps are like this. 


"There aren't many places where even a small amount of leakage can be tolerated but there are a few. Often a capacitor is connected from some part of the circuit to ground. These are usually called "bypass" capacitors. That's not a special kind of cap, just the way it is being used in the circuit. If the resistance associated with the cap is not too large it can work for many years with a small leakage current. If it is a screen bypass cap it may lower the screen grid voltage and lower the gain of the amplifier stage. A leaky cap in the AGC circuit of a receiver may or may not have a significant effect on its operation."


reference: http://www.angelfire.com/electronic/funwithtubes/Testing_caps.html

[shooter]

this acceptable

once you get into~~~ .5vdc or more.  current will always find it's way home, so expect leakage laying around in small quantities

[mresistor]

Thanks Shooter - so when you encounter >= .5vdc you would start unsoldering some cap leads to find and replace the leaky cap?   


I am surprised that the original blue tone caps in old Fender amps are still working in most cases.  However I have seen a few amps where wholesale replacement of all the molded caps was done.

[mresistor]

Also it was this thread that piqued my current interest on this subject.    https://el34world.com/Forum/index.php?topic=24100.0


I'm wondering if 1mv leakage is really a cause for concern. 1mv might be present on the pots but after lifting the cap leads is it possible the dc voltage is higher? Is 1mv or 2 mv a cause to start checking the tone caps?

[shooter]

fixin stuff for a livin I developed different than most 
up til the late '90s you shot to a component level, once I had the "area" nailed down, pull 'em all, swap in new ones, go play.  my co-workers were still "analizin and postulating"