Symptom:
During "Full Break-in" operation the SWR meter shows infinite SWR at the beginning of transmission. This results in a reduction of the transmitter power, followed by a gradual increase to normal full power. This symptom does not occur with the antenna tuner set to "THRU".
Cause:
Normally the RCB line should be 0 Vdc at the beginning of transmit operations. We have found that this does not always occur. The length of time required for transmit power to return to normally is directly related to the time constant of capacitor C128 on the RXB line.
Correct action:
Removing this capacitor corrects the above symptom, but might affect the receiver sensitivity at a dial frequency of 100 KHz. This action is only recommended if the symptom is actually present. Do not modify the unit if the symptom is absent.
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Caution: This modification requires soldering equipment rated for CMOS type circuits. It also requires familiarity with surface mount soldering techniques. If you do not have the proper equipment or knowledge do not attempt this modification yourself. Seek qualified assistance. |
Time required for this modification is 30 minutes or less.
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