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Troubleshooting
IMPORTANT: If you take any corrective action for a KAT100
problem, be sure to turn off all power supplies, then turn on
the KAT100's power supply first (if it is separate from the K2's
power supply). Otherwise, the K2 may not be able to establish
communication with the ATU. If it is not convenient to turn the
KAT100's power supply off, disconnect its power input (J1) for a
few seconds.
General Troubleshooting
If your specific symptoms are not covered below, do a complete visual
inspection of the KAT100 circuit boards. Look for reversed diodes,
leads not soldered (or not clipped), backwards ICs, and broken wires or
components. Make the resistance measurements from earlier sections,
and test all diodes in-circuit. Check continuity between the
pads
of all
toroids (not the leads themselves).
Control or Menu Problems
KAT100 not recognized by the K2 (ANT1/2 switch not working,
or ATU menu parameter missing):
This could be due to a power
supply problem; some switching power supplies show a "bounce"
downward in voltage a few hundred milliseconds after being turned on
or when loaded by attached equipment. This could prevent the K2
from sending its initial auxBus message to the KAT100. If the power
supply is OK, make sure the KAT100 microcontroller, U1, is fully
seated in its socket and is not installed backwards. Look for bent pins
(you may need to remove U1 from the socket to find them). Make
sure the control cable is wired correctly. Also check Z1 (ceramic
resonator) and R5 (auxBus series resistor). Check both the RF and
Front Panel boards for shorts to ground, solder bridges, and unsoldered
connections.
I N F O
messages
: If you see
I N F O 0 8 0
or a similar message on the
LCD, refer to the K2 Owner's Manual, Appendix E.
Missing sidetone:
You may have the wrong sidetone source selected.
Select the
S T L
menu entry and
E D I T
its parameter, then tap
D I S P L A Y
.
Transmit or TUNE problems
Erratic tuning in
A U T O
mode:
This is much more likely to occur
at high power, and could be due to
high RF voltages on the K2 chassis,
mic, key, power supply leads, or KAT100 control cable. First, try
reducing power to 10 watts or less. This will force auto-tune to be done
at 2 watts.
If this cures the problem, you may need to add RF bypassing
to your power supply, key, or mic; improve your ground system; move
the antenna farther away; or use a "choke balun" between the ATU
and the transceiver. If this doesn't cure the problem, you may have a
defective L-network inductor, capacitor, relay, or relay driver IC (U2-
U4). You can use the KAT100 menu to troubleshoot the problem to
the component level (see
Testing Relays, Inductors, and
Capacitors
, below).
Even though SWR reads 1:1, K2/100 power is limited:
The SWR
displayed on the K2's LCD and the KAT100 SWR LEDs originates
from the KAT100's SWR bridge. The KPA100 module has its own
SWR bridge, which could be seeing a higher SWR reading than the
KAT100. In this case the KPA100 may request power reduction. If
power seems to be getting limited to an artificially low level, re-check
the KPA100's SWR bridge alignment. You could also have any of the
RF feedback problems listed under
Erratic tuning in
A U T O
mode
.
Erratic power control with K2/100:
During key-down, the K2/100
power output should follow the setting of the POWER control, with
only minor adjustments every second or so to correct for upward drift
of the power level. If the power level indicated on the K2's LCD or
bargraph seems to "jump" continuously and never settle down, it is
probably due to RF getting into the KAT100 control cable. This is
usually just an aesthetic issue, and will not cause trouble. However, you
can try soldering a .01 µF capacitor from pin 7 to ground (inside the
backshell).
