There are several readings from earlier that are confusing. I think many are due to how they are being measured.
But based on latest info:
If TP4 is correct then don't mess with the 5V regulator circuit including Q3.
Note that he is not a standard transistor, he is a "Darlington Pair" transistor which has two transistors in the package. These do not test the same as normal transistors do.
TP1 -- you need to measure the 'setting voltage' which can be found at location "E2".
Meter grounded to TP3 - what voltage do you get at "E2".
It is a little high but not horrible. About 10% out of whack when it should be closer to the 5% range.
TP2 is fine. When you fix TP1 then TP2 will fall in line.
TP2 is calculated by voltage at TP1 minus 18V. You normally get about 60 - 18 = 42V. You get 68 - 18 = 50V. This says CR6 and R5 are good.
TP5 is bad. Replace CR7 and R10.
Out of curiosity: meter grounded to TP3 - what voltage do you get at "E4"?