Vintage fender BF PR testing Blue Ajax caps

[bohema79]

Hi Guys,
Is there a good way to test the two Blue Ajax .1 Pi tube coupling capacitors for leakage in a bf Fender PR?
I've tested the rest of the caps but these two give me some problemems because the negative voltage is on both ends.

Thank you for the help.

[sluckey]

Is there a good way to test the two Blue Ajax .1 Pi tube coupling capacitors for leakage in a bf Fender PR?
I've tested the rest of the caps but these two give me some problemems because the negative voltage is on both wides.

To test for leakage you need to lift the end of the cap that is NOT connected to the PI. Then connect your meter leads between chassis and the dangling end of the cap. The higher positive voltage you have, the higher leakage you have.

[bohema79]

Hi,
Thank you for the help.
I did as told and the caps seem to be fine!

[6G6]

Those old blue ones usually are. 

[eleventeen]

Those seem to stay working pretty well....I got perhaps a hundred of them out of an old CONN organ but unfortunately, 90% are 200 volt rated.

[bohema79]

Guys, can someone please tell me what's the function of the .1 large "blob" capacitor and the other .02 ceramic disc next to it in the vintage Princeton Reverb?

Thanks!

[sluckey]

The .1 is a coupling cap between the LFO plate and the intensity pot. It passes the LFO signal but blocks dc voltage.

The .02 is just a small filter for the LFO signal.

[bohema79]

Thank you sluckey!
Do these caps have any impact on the tone of the amp or is it just the tremolo?