Elecraft T1 ATU Owner's Manual - Manual (Page 10)

10
Troubleshooting
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If you need to open the T1 to do testing or replace parts, use an anti-static mat or touch a
grounded metal surface occasionally. This will help prevent ESD damage to sensitive components.
T1 doesn’t turn on: Make sure you’re using a fresh 9-V battery. Verify that the MCU is installed in the
correct orientation and is plugged into its socket as far as it will go. Also check for proper mating of the
connectors on the Control board. Try unplugging the remote control cable (if applicable).
Intermittent failures: If the T1 suddenly stops working, it may be because the transceiver’s supply voltage
is being pulled too low during transmit. This is especially likely if you’re using a battery and maximum
power output. Try reducing power, recharging the battery, or disconnecting the remote-control cable.
T1 fails to find a match, stops tuning, or turns on by itself: Such problems can be caused by RFI due to
a poor ground, an end-fed antenna (especially if it’s close to1/2-wavelength long), or an antenna placed
close to the transmitter. Try improving your ground system, moving the antenna farther away, altering its
length, or using a balun (see page 9). Using high power will worsen RFI, especially on the highest bands;
try 2-5 W for initial tune-ups. Typically the T1 will reset itself and recover from excessive RFI after a few
seconds. If it continues to be unresponsive, remove and reinstall the battery. If problems only occur with a
remote control cable connected, try a shorter cable and/or better shielding. Also make sure the T1 is not in
bypass mode.
T1 causes interference on receive: You may hear harmonics of the T1’s MCU clock or other odd sound
effects while the ATU is turned on. These should cease when the ATU turns itself off. If not, the MCU may
be in an unknown state due to excessive RFI during a previous transmission. Remove and replace the
battery if this occurs. If that doesn’t fix the problem, try re-seating the MCU and the Control PC board.
SWR indication on the transceiver doesn’t match the T1’s: SWR bridges vary in sensitivity and
accuracy, if calibrated at all, especially at frequency extremes. Some rigs also roll back power at high
SWR. This can make SWR read lower than reality during auto-tunes, making it appear that the T1 has not
selected the best match. In any case, such discrepancies rarely matter (see SWR discussion on page 9).
PWR indication is always about 0 watts: The windings of transformer T1 or T2 may be reversed, or one
or more leads of T1, T2, or L1-L7 may not be properly stripped. Also look for a short in the L-network.
SWR indication is higher than 1.0:1 with a 50-ohm load: An antenna tuner can usually tune out its own
stray reactance. However, if the T1’s SWR is higher than 1.5:1 into 50 ohms on some bands in bypass
mode, check the relays and L/C network components using TEST mode (see procedure below).
T1 is unable to achieve a low SWR on some bands: Make sure the tuner is not in bypass mode (see page
7). You could also have a defective relay, inductor, or capacitor; use test mode (page 7) to test each L and
C by noting their effect on SWR. Insert a sensitive SWR bridge between the transceiver and the ATU, and
connect a 50-ohm load to the antenna jack. Start on the highest band. Select L0, key the rig, and note the
SWR. Then select L1 and key again; the SWR should change by a small amount. L2 should have a larger
effect, etc. If the SWR goes above the meter’s scale, switch to a lower band to test the other inductors.
Similarly, check C0-C7. Look for a part that has a disproportional effect on SWR in relation to others.