Vintage EH Memory Man suddenly dark sounding and volume drop.

[BDuguay]

I have this very clean non deluxe memory man that has been modded to include a pot for volume where the "Boost In" input once was. This pedal was functioning fine but now it has gotten very dark when engaged and exhibits a slight volume drop. The volume discrepancy might be a byproduct of the loss of high end however. The added volume pot still works.
Does anyone have a suggestion as to where to begin sorting this out?
Thanks as always.
B.

[R.G.]

How vintage is vintage?  If it's a survivor of the 70s or 80s, I personally would replace all the electros and see if it gets well. There are a number of syndromes that give you tone change with failing or decrepit electros. You could save a lot of time, and at the same time give it a much longer life by doing this. And if that was not THE problem, it certainly won't hurt it if you don't accidentally fump up the replacement.

[BDuguay]

70's for sure. I was wondering about that very suggestion. Especially since this is an AC unit. Thanks R.G.
B.