• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Help with Hickok 539C!

HELP WITH HICKOK 539C!
Hello everyone, I am writing with the hope that someone with more experience in the repair and calibration of this equipment can help me, I am calibrating the Hickok 539C and so far everything is going well except that when I set the function switch to H the fuse lights up brightly. , I only found this when it is set to H, I don't know if this is normal or there is some problem (short) in this switch, any help will be greatly appreciated.
greetings
Alex
20240520_095039[1].jpg