Some ideas:
(1) I think you could use some more heat on the 8 pin socket - and quite possibly on other joints. What solder are you using? If it's Cardas Quad, you should see brown flux come out of the joint and settle on the surface of the solder. If it doesn't rise to the surface, it's insulating the inside of the joint. If you have an adjustable soldering station, try cranking it up to at least 750F.
(2) You've painted the bottom of the chassis and I see that you've scraped the paint away from at least some of the terminal strip attachment points. But I can't tell the full extent of the scraping. I would make sure that the paint is scraped away from any terminal-strip-to chassis connection to which a black wire attaches. But I doubt that's what causing your negligible voltage at T7 since you have the correct voltage at T9.
(3) Purely for the sake of future reliability, I suggest pushing the leads of the "internal" diodes (the ones closest to the power transformer) farther into the terminal lugs and then trimming the excess on the other side.
All that said, I think your best and fastest route to a working amp is to reflow all the joints, making sure that they get a good heating, and adding just a small dab of solder (unless there's a solder blob there already, in which case don't add any -- or better yet, remove most of it with a sucker or wick and redo the joint).
That's all I can think of. PB may have some better pinpoint suggestions.
cheers and good luck, Derek
