AL-80A Bandswitch #1 This is one of the three wafers from the original bandswitch. The two leftmost contacts have evaporated due to arcing.


AL-80A Bandswitch #2 This is what happened to the bandswitch that replaced the bandswitch shown above


After bandswitch number three was installed, the amplifier's owner, Rick May, KC0HH, heard bandswitch number three arcing, he began to suspect that the arcing might be due to an intermittent VHF parasitic oscillation. Rick subsequently installed low VHF Q parasitic suppressors. So far, he has experienced no bandswitch arcing.

The bandswitch below was removed by Bud Henley from a (3) 8874 Alpha amplifier. The bandswitch was replaced with a new unit, and low VHF Q suppressors were installed. Bud said that no arcing was observed during bench testing. The amplifier was returned to its owner and placed back into service.

VHF parasitic-arced Al-80 bandswitch, courtesy of George Drysdale, WA6ALQ

.Reverse Side:

Arced bandswitch removed from an Ameritron AL-82 (2, 3-500Zs)

Even though the contacts are still intact, the bandswitch is unusable because the ceramic insulation is coated with conductive material: (Courtesy of an amplifier repairman who wishes to remain anonymous. )