Collins 30L-1 Amplifier Tube grid to plate short Protection

Description

Collins 30L-1 Amplifier Tube grid to plate Protection MOV. New 811A tubes short more often vs older tubes and is the number 1 failure of the Chinese 811A tubes. The Collins HV power supply will discharge the capacitor bank and whatever transformer available until the fuse blows. This is a quite a few amperes and ten times the bias circuit & relay voltage. Explained here:
'HIGH VOLTAGE FLASH: A more destructive process can also arise : a metallic particle due to a bad manufacturing process , a shock , or everything you have, can move around the electrodes into the tube glass envelop and cause a short between grid and plate : this is very dangerous and destructive not only for the 811's but also for the bias circuitry including the antenna relay coil (a difficult part to find) plus short the bias diode that will ruin th4e transformer winding. A good solution is easy to find a MOV that can be soldered parallel to C2 and as the voltage at this point can be as high as 170VDC, any MOV around 200 or 250V can be used'.
The MOV offered is rated at 180 VAC and 230 VDC.
Ships free to USA.