Elecraft KPA500 Owner's Manual - Manual (Page 8)

8
 Close the cover and be sure the fuse block is oriented correctly showing the proper mains voltage
as shown below:
If you are setting up your just received factory-built KPA500 or a just assembled kit, the transformer tap
is already set for either 116 to 126V or 231 to 250 V. Go directly to “Test the power supply voltage
output” on pg 10 to determine whether you need to adjust the tap as described below. If you are
reinstalling the amplifier in a new location and are unsure of the tap setting, open the top cover to verify
that the correct tap is set before applying mains power.
Power Supply Transformer Tap
WARNING
If the KPA500 has been previously turned on, tap the front panel O N switch to turn
it on, and then tap it again to turn the unit off and wait for the fan to stop before
removing mains power. This drains the power supply to a safe voltage. When the fan
stops, remove mains power at the rear panel. (Units shipped from the factory are safe
to open without turning them on first).