A click noise might be generated when receiving a strong signal (S-0 or above) when the NOTCH is ON and the Notch Control is turned away from the notch point.
Lengthening the AGC release time of the IF Amp just before the NOTCH circuits will correct this symptom. The enclosed modification has been designed to change the time constant only when the NOTCH circuit is activated. Do not install this modification on sets that do not exhibit this symptom as the AGC FAST time constant affected by this change.
- Cut the printed circuit foil pattern between the test point (TP) and gate 2 of Q2 as shown.
- Install the 47 Kohm chip resistor from TP tp gate 2 of Q2.
- Add a 0.047 µF ceramic capacitor as shown in the accompanying illustration.
- Add the DTC124ES transistor as show.
Note: The .047 µF capacitor and the digital transistor must be connected together as shown and installed so that they do not touch the sorrounding board patterns.
- Install a jumper wire from the base of the digital transistor to pin number 6 of CN14.
Qty Description Kenwood Part No. Circuit description
1 0.047 µF capacitor CK45B1H473Z NA
1 Digital transistor DTC124ES NA
1 47 Kohm chip resistor RK73FB2A473J NA
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.