The good news is that I actually am relating the parts you mention on the schematic and then finding them on the actual board, and have researched that diodes will read continuity when read with proper polarity, and should have no continuity when opposite polarity is observed. Yeah!!!!!
The bad news is I think I might have to completely remove the board to measure diode bridge DB1 from the opposite side of the board to access the contact points(the side opposite the tubes, resistors, etc......??? Is that true?
I also see the wh1, wh2, blk1 right in that area of DB1 on the actual board itself, not showing in the schematic, but that probably relates correctly to your read of the other schematic where you wanted me to disconnect wh1, wh2 in our initial test that you wanted me to try(after I get the proper fuses).
Are you in the U.K. or U.S.A., as "T" from U.K. in U.S.A. appears to be called "slo blo"(time delayed) fuses, in which case the ones I have might be alright.....as I am in the U.S.A........does that sound o.k.?
I know this must be like trying to teach a baby to fly a jet plane, but i'm slowly getting a sense of this, so please stay with me teacher...!!! I'll make you proud, I hope..!!!