I'm working step by step on the aforementioned Tek 603, and I got it
into a state where the DC rails are all within spec.
The next challenge was why the intensity control is unresponsive and why
focus couldn't focus the beam.
I found that the Z amplifier output could not be trimmed (per
"Check/Adjust CRT Operation") to 10V using intensity and in fact the
collectors of the output stage (Q554/Q556) were closer to 82V.
To continue testing that board, I'm thinking of:
- leaving the deflection amps disconnected from power (which is bridged
via the Z amp). Or will that disrupt regulation load too much?
- disconnecting the CRT heater, because with the deflection amps powered
off, the too-bright beam can't be directed off the CRT face. I could
also disconnect all high voltage CRT connections.
Are these bad ideas?