Assuming it's like the similar 4 channel UHF unit I had it also has an interesting quirk - if the bulb is blown then the associated channel is skipped even if the channel switch is turned on, because the scan circuit uses the current through the lamps to determine if the channel is enabled.
Assuming it's like the similar 4 channel UHF unit I had it also has an interesting quirk - if the bulb is blown then the associated channel is skipped even if the channel switch is turned on, because the scan circuit uses the current through the lamps to determine if the channel is enabled.