My T931 had screen cranked even though CRT emissions was good. It turned out that
the horizontal blanker tube V19 (6GH8A) was tired, and when that tube gets tired the DC bias of the picture tube G1 anodes becomes very low. So you should try swapping that blanker tube for one that is know to be good.
In fact, the only low emissions tubes in my T931 were the three 6GH8A tubes. Chroma demod didn’t work until I replaced the 6GH8A that was used for the chroma oscillator. The T933 chassis is almost identical, so consider swapping those 3 6GH8A tubes out for NOS.
All of the electrolytics were still within spec too, except the two on the convergence control board.
My T931’s flyback looks great too. I think it is due to the fact that the horizontal efficiency coil was tuned for absolute minimum horizontal output tube cathode current. Tuning that coil doesn’t just decrease wear of the HOT, since the HOT is in series with the flyback transformer, that coil’s tuning decreases the wear and tear of the flyback transformer.