TA LE II — TROU LESHOOTING HINTS
SYMPTOMS
1. Won't turn on; nothing happens
when ON button is pushed.
2. Relay closes (and blower may start)
but no HV or meter illumination at
turn-on.
3. lower starts, HV normal, but met
ers do not switch to green and amp
lifier will not switch to transmit.
4. Grid meter "pins" at low drive.
5. Low grid current, excessive input
VSWR (abnormal exciter loading),
low rf output.
6. Plate current flows in receive or
ST Y conditions. See also (9).
7. Low drive and output power; cannot
drive exciter to normal input or
rf output levels.
8. Flashover in RF compartment, usu
ally between load capacitor plates.
9. Plate current flows in receive or
ST Y and cannot drive amplifier;
abnormal exciter loading.
10. Distorted SS output signal;
possible severe TVI.
POSSI LE CAUSE/CURE
a) External a-c wire, fuse, or breaker
b
c
a
a
b
a
a
b
a
b
a
a
b
c
d
a
a
b
c
open or missing.
Cover a-c interlock switch open.
Fuse FI or F2 blown or missing.
Step-start relay K2 not closing; pos
sible blown fuse F3, defective +28V
supply (D107-D108 or Cl08), or HV fault.
Defective reed relay K6.
Defective Q101, Q102, or Cl09.
R116 open or damaged.
ias zener DUO damaged or open.
R116 damaged or open (grid current will
indicate very high as in (4) above).
8874 tube leakage or short, cathode-to-
grid or-heater.
D106 damaged or defective.
ALC sensitivity control R209 set im
properly; unplug ALC to check. See
note at bottom of this page.
Excessive load VSWR; mismatch or wrong
antenna; defective rf cables or plugs.
Insufficiently heavy loading and/or
excessive rf drive power.
Dirt or other contaminant in capacitor
plates.
If chronic, capacitor plates damaged by
previous arcing.
8874 tube short, cathode-to-grid or
cathode-to-heater.
Excessive rf drive power and/or inade
quate!y-heavy loading adjustment.
Flashover of variable capacitor on peaks
Antenna or feedline (or balun or trap)
arcing on voice peaks.
d) RF feedback from antenna into exciter,
microphone or speech processor lines.
NOTE: If exciter manufacturer does not provide instructions for adjustment
of ALC with an amplifier, set trimpot R209 for the desired amplifier
plate current meter swings on voice peaks, and adjust exciter mike
gain for the degree of ALC action desired for normal exciter operation.
