Occasionally during operation of the AT-940 a VSWR greater than 1.5 to 1 might cause overloading of the relay contacts in the antenna tuner. This may be especially noticeable when switching BANDS, or if TUNINS is performed too frequently. The following procedure should reduce or eliminate the tendency.
Parts Required
Q69: Digital transistor, (DTC124ES)
R304: 5,6 Kohm 1/6 Watt Resistor, (RD14BB2C562J)
Procedure:
- Add the circuit as shown below.
- After the circuit has been installed adjust VR4 for a 10-15 watt output when the antenna tuner operates.
Time required for the modification is 1 hour or less.
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