Switching noise from the main band noise blanker circuit may be induced on the 15V line and pass through the AF amplifier to the speaker. The following modification will correct this condition.
Note: This modification has already been performed on models starting with serial number 104xxxx.
120 ohm, 1/8 watt resistor (RD14BB2B121J)
100 µF, 16 V electrolytic capacitor (CE04EW1C101M)
- Disconnect the power cord and antenna.
- Remove the top and bottom covers (18 screws).
- Locate the AF board. This is the front left board of the 4 boards on the bottom of the transceiver.
This work will be done on the component side of the AF board.
- Cut the foil shown in the accompanying diagrams.
- Add a 120 ohm resistor between the emitter of Q48 and the 15 V line.
- Add a 100 µF, 16 V capacitor between the 15 V line and ground.
- Reassemble the transceiver.
This modification is covered under the 1 year warranty.
Time required to perform the modification is ½ hour.