Testing

120V Initial Testing

• I installed the original 4CX1000A tube which came in my amplifier. Only the 3.2A fuse was installed, and I applied power!
• The meters illuminated; after the time-delay relay closed, the dials also illuminated. The "ON / OFF" switch functioned.
• Opening either the top-lid or the front-panel removed the dial-illumination, and prevented operation of the "ON / OFF" switch.
• I tested the Thermal Overload switch K102 by moving it out of, and back into the airstream - it works, and disables the "ON / OFF" switch when there is no airflow over the sensor.

The Safety and Control seem to work. The Bias and Filament adjustments work.

Reasonable correlation between panel-reading and at-the-socket measurement

I clipped some test-leads right onto the tube-socket, in order to measure and adjust filament-voltage accurately. Eimac specifies 6.0 +/-5%, so that's what I gave it. The panel-meter actually reads the incoming 115VAC supply, using that as a proxy for the actual filament voltage - you can see this does a pretty good job.