Pro Reverb Mod Ideas

[foreverstrung]

Got a little snag. I started really messing with the inside of this today and found my power tubes getting way too hot. My plate voltage is 500 DCV and using a bias meter i'm getting 70/74 mA when I dial the balance trim pot on the back of the chassis to the lowest setting. (when I turn it in the opposite direction, one tube will go down into the 60's, but the other will get up to 80 mA). One tube was red plating. I did not leave it on, of course. I purchased the BMK bias upgrade for this amp, but while I wait, any suggestions to bring this bias down? I'm getting -58.4 at pin 5.