Elecraft KX1 Manual - Manual (Page 90)

E-3
VFO (40-59)
Problem Troubleshooting Steps
40 General VFO
(DDS) problem;
frequency jumps or
drifts ƒ Note: A small amount of DDS drift may
occur due to aging of components and
heating/cooling of the cabinet
ƒ Check 14 MHz LPF components (L4, L5,
C50-C52) and buffer (Q1, R31)
ƒ Make sure supply voltage is above 6.5V
ƒ Check values of R8, R6, R7, RP4, RP3
ƒ Check 5V and 2.7V regulator output (23)
ƒ Check installation of Z2 and U2 (both surface
mount--use magnifying glass)
41 Can't tune VFO (or
RIT offset) ƒ VFO may be locked ( see Operation)
ƒ VFO or RIT offset may be at end of range
ƒ See 40, above
42 No DDS output ƒ See 40
Receiver (60-79)
Problem Troubleshooting Steps
60 Low (or no) audio
output from receiver,
or general receiver
gain problem ƒ If you hear normal audio output on one band
but not all bands, see 62
ƒ Make sure you have headphones or speaker
connected; turn AF GAIN clockwise
ƒ Check the key jack for a short to ground
ƒ Make sure RF GAIN is fully clockwise
ƒ Re-peak the band-pass filters
ƒ Check for ground shorts in the LPF and BPF
ƒ If you don’t hear any “hiss” at the receiver
output, troubleshoot the AF amplifier (65)
ƒ Check the 6V regulator (20)
62 Signal loss only on
one band ƒ Re-do alignment on affected band
ƒ Check the band-pass and low-pass filters and
crystal for this band
ƒ Check functioning of the relays (change
bands, then measure relay leads that should
be open or shorted for that band)
65 AF amplifier not
working ƒ Use the STL menu entry to set a sidetone
level of 3 . If you hear a strong tone, the A.F.
amplifier (RF-U4) is probably working, and
the problem is likely to be with the mixer
(RF-U6) or other RF board circuits.
ƒ Signal trace through the receive chain
backwards by touching a tool or wire to
various points along the receive path
ƒ Check all DC voltages in the receiver
ƒ Inspect the A.F. amp circuits
70 AGC or S-meter
not working ƒ Check R5, D4, C53, Q9, R20, C8, and L9 for
incorrect values or unsoldered leads
Transmitter and Keyer (80-99)
Problem Troubleshooting Steps
80 General
Transmitter problem ƒ If power output is too low, go to 86
ƒ If power output slowly increases during key-
down, go to 88
ƒ If current drain on transmit is too high for the
given power level, go to 92
ƒ If the transmitter output power seems to be
unstable go to 88
ƒ If the transmitter stops transmitting by itself
go to 90
ƒ If the keyer isn’t working properly, go to 95
86 Power output is
low or zero ƒ Make sure the power-output control, R4, is
set fully clockwise
ƒ If the top cover is removed, make sure you
don't have a screw inserted into the tab of Q6
ƒ Unplug the ATU (KXAT1) and insert a
jumper between pins 1 and 3 of J7; connect a
dummy load at J2. If this solves the problem,
see the KXAT1 manual's troubleshooting
section.
ƒ Check power output when using a 50Ω
dummy load; if the output is correct on a
dummy load but not when using an antenna,
your antenna is probably not matched
ƒ You may have a short in the LPF or BPF or