With a little more time on my hands at home these days, I plan on replacing the electrolytic caps in my RE Designs LNPA 150 Amps (made by Dan Banquer). I wish Dan was still around to ask, but there seem to be some knowledgeable people on here, so don't be shy.
Here are the amps.
An overview, looking down at the two mono amps.
I bought these used so I don't have their complete history but they seem to have the Vishay bulk metal foil resistor upgrade.
My first question - There seems to be a powdery/crystalline substance on the inside floor of both amps. See pics below. Is this leakage from the big electrolytics, or is it some kind of old heat grease used on the bridge rectifiers? Or maybe it is degraded sealant that was intended to prevent corrosion of the aluminum case, or just junk that blew in the vent holes?