1) RELAY (T/R) control cable from transceiver is shorted.
2) Transceiver locked in transmit.
I) Plate current indicated when amplifier is in STBY or receive.
1) 4CX800A/GU74b tube heater-to-cathode leakage or short.
2) Tube bias supply or T/ R bias switch faulty.
P Distorted SSB signal; possible severe television interference.
1) Excessive RF drive from transceiver and/or insufficient amplifier loading.
2) Coaxial connector, coax feedline, antenna feedpoint balun, tuner, or antenna trap
arcing on voice peaks.
3) RF feedback from antenna into transceiver via the transceiver power cord, micro
phone or key cable, or other unshielded station patch cables.
4) Poor station RF ground.
K) Low frequency audio hum on transmitted signal.
1) Defective microphone cord (especially, broken ground lead).
2) Dynamic (magnetic) microphone located within about two feet of 91/3 power
transformer. All dynamic microphones pick up some magnetically-coupled hum from
the external field of nearby power transformers. In cases where objectionable hum is
experienced while using the 91/3 and popular microphones such as the Heil series,
the problem usually can be resolved by keeping the microphone at least 18 to 24
inches from the front of the amplifier and insuring that transceiver mike gain (speech
processing) and internal drive (ALC) levels are not adjusted to exceed 10 dB. In rare
cases it may be necessary to use a ceramic or condensa- type microphone.
16
To Next Page
Loading...
