Unless there is a track break or bad connection in that area I'm not sure what else to suggest, I've had a quick look at the pictures of the power supply boards in mine, none of the adjustment pots are at the end stops, do they all actually change the output voltages when adjusted?
The discoloured board around the resistors, mentioned earlier may indicate your 140T has had a lot of use, none of mine are like that.
Also one of the manuals (140A 1967) mentions that the measured voltages on the circuit diagrams may vary depending on the plug-ins fitted, of course with no load (no plug-ins) that may explain the higher voltages before the regulator transistors.
As for the calibrator, the outputs are a 1V & 10V peak to peak square wave at mains input frequency (i.e. 50Hz or 60Hz depending on country), did you use an oscilloscope to check this?
The transistor Q490 is germanium type, they have a lower forward voltage than silicon types, but if it's reading 0.2V (base to emitter) both ways (out of circuit) then it's leaky.
One important thing with the calibrator circuit, DO NOT measure the tunnel diode (CR490) with your DMM as they are very easy to destroy, they can also be damaged very easily with the heat of soldering.
David