tektronics 475 sweep

[pa0nvd]

I am trying to repair a tek 475. The sweep seems without  a capacitor connected across the integrator, there is sweep, but VERY high frequency. It depends upon the timebase switch, so the current source for the integrator works. The variable TB also works. The TB is that fast that it seems RF oscillation.
I did verify that the TB capacitor bank marked A (between Q920 and Q922) indeed is connected and I can measure the capacitor bank of the TB switch at pin 6 and 12 of J6.  I did measure all transistors and FETS and they seem all ok.
When I pull the time base switch to engage the delayed time base, there is a microswitch upon the switch unit for the time base that actuates at the moment of pulling and when the TB switch is in a delayed position. . Than there is a normal sweep, but the variable TB doesn't work anymore. When I acuates only this micro switch, the scope works, good triggering etc., but the variable TB does not work.. The microswitch switches 5VDC on and off to the timing PCB. This microswitch is a simple on/off unit, the NO is not used. I can not find this microswitch in the schematic diagram or the description. When I actuates the microswitch, the voltage at the output goes to zero. Also pin 1 of J6 goes to zero and the TB works.
Without knowing what the microswitch does and where it is in the diagram, I am puzzeled
Please some chime in to help me

 

[pa0nvd]

Problem solved
Q1018 in the sweep generator was bad 
Further problems earlier solved were a leaking Q1316 in the HV/Zaxis part resulting in a -1kV at the CRT Cathode instead of -2.45 kV and a bad Q746 in the trigger generator.
Now just calibrate and enjoying this marvelous scope