no CRT connected?

[old_tv_nut]

Need to keep the B+ loaded to keep it from going too high, so yes, should keep the sweeps running for trouble shooting. The horizontal and high voltage particularly depend on having the yoke connected.

For Tuner/IF alignment, though, the voltage pulses and ground currents from the sweeps may disturb the scope waveforms; so some chassis alignment instructions include disabling the sweeps and using a specific large power resistor to load the B+.