Hi, I have a 1967 Blackface deluxe reverb AB763. The power transformer is marked F025130 606-9-15. I assume it is not original. The transformer has only one wire going to ground. I notice in the layout that ab763 power transformers have 2 wires going to ground. I see that ab763 and ab868 use the same transformer number but on the layouts ab763 has 11 wires with 2 wires to ground and ab868 has 10 wires with one going to ground. Are the 11 wire versions of the 025130 really interchangeable with the 10 wire versions? Is there a difference in their function? Is it safe to use the 10 wire version 025130 on the ab763? Does the "F" that is stamped before the 025130 have any meaning? I really appreciate any input on this matter. Thanks, Bob