Elecraft KX1 Manual User Manual
Page 91
E-4
an incorrect LPF component value
Check relays (25)
Examine T1, L3, L1, and L2 for poorly-
stripped leads
Check T1 for backward windings
Check all DC voltages in the transmitter (Q1,
Q4, Q5, Q6)
Signal-trace through the transmitter to find
where signal is lost (using an RF probe)
Check for any components getting hot
88 Power output
fluctuates
If you stay in key-down (TUNE) mode for
several seconds, it is normal to see some
increase in power; this is due heating of the
final amplifier transistor.
If power goes up and down significantly
during normal keying, you may have a
poorly-matched antenna OR you may have
power set too high for your battery or power
supply to handle; try reducing power or
replacing batteries
If the transmitter is unstable (oscillating)
even when connected to a 50-Ω load, you
may have an incorrect component value or a
toroid-winding error (86)
90 Output power
drops to zero suddenly
If you have transmit power set too high for
your battery or power supply, the supply
voltage may drop so low on transmit that it
resets the MCU (U1); try a higher supply
voltage or fresh batteries
If there's no ATU installed, verify that J7
(ATU connector) is bypassed with a jumper
between pins 1 and 3
92 Current drain too
high on transmit
You may have power set higher than the final
amplifier can achieve for a given load or
power supply voltage, resulting in overdrive
of transmitter stages. Reduce power to see if
normal current drain is restored.
Damaged PA transistors or other components
could cause inefficiency in any stage of the
transmitter. Check all DC voltages and
components; signal trace if necessarily (86)
95 Keyer Problem
If the keyer is generally erratic when
transmitting and seems to get worse as power
is increased, you probably have RF leaking
into the keyline. Try bypassing your key with
.001 µF capacitors; also try 100 µH RF
chokes in series with the paddle connections.
Seek a better antenna match
Improve your ground system