Kenwood TS-950S - User Manual

ASB-982
Service Bulletin Amateur Radio
Division
Subject: TS-950S/SD TX IMAGE ON 18.115MHZ Date: 02/06/91
Some TS-950SD owners have reported a transmit image at
18.115MHz that causes the receiving station to hear
distortion on the carrier. If the operating frequency is
shifted 3KHz above or below 18.115MHz, the image
disappears. This modification will lower the image level
from -30dB (worse case) to better than -40dB by
installing a trap on the 455KHz I.F.
REQUIRED PARTS:
4pF TRIMMER CAPACITOR C05-0308-05
40pF TRIMMER CAPACITOR C05-0309-05
2.2uH COIL L40-2292-14
MODIFICATION:
1. Disconnect the power cord and antenna.
2. Remove the top and bottom covers (18 screws).
3. Locate the I.F. board on the bottom of the
transceiver. This is the back right board of the 4
boards on the bottom of the transceiver. Figure 1
4. Locate L36 by connector CN17 on the I.F. board.
Figure 2
5. Install and solder into place a 4pF trimmer
capacitor across L36. Figure 3
6. Install a 2.2uH coil and 40pF trimmer capacitor in
series from the output of L36 to ground. The can of
L31 can be used for ground. Figure 3
ALIGNMENT:
1. Connect the TS-950S/SD to a power meter and 50 ohm
load.

Summary

TS-950 S;SD TX Image Modification

Required Parts

Lists the necessary components for the TS-950S/SD TX image modification.

Modification Procedure

Detailed instructions for performing the hardware modification to reduce transmit image.

Alignment Procedure

Steps for aligning the transceiver after the TX image modification.

Kenwood TS-950S Specifications

General

Antenna Impedance	50 ohms
Supply Voltage	13.8V DC
Weight	15 kg
Modes	SSB, CW, AM
Receiver Type	Superheterodyne
Image Rejection	80 dB or more
IF Rejection	>80 dB