When the VOX switch is turned on immediately after the power switch is depressed, the TS-140S may trip into the transmit mode. This condition can be corrected be changing the value of chip capacitor C504 on the Signal unit. The following procedure will detail how to access the capacitor.
Required parts:
C504 0.001µF, 50V chip capacitor (CK73FB1H102K)
- Disconnect the TS-140S from the antenna and power supply.
- Remove the top and bottom covers (12 screws). Remove the 4 sub-chassis mounting screws. Swing the sub-chassis to the left to expose the Signal unit. If required, refer to the instruction manual for illustrations.
Note: Refer to figure 1 for the next steps.
- Unplug the wires at connector CN4, CN12, CN18, CN19, and CN20.
- Remove the nine screws from the signal unit.
- Slide the Signal unit forward until the external speaker jack clear the back panel cutout.
- Carefully lift the Signal unit up from the back side and rotate it toward the front panel to expose the bottom of the board.
- Locate chic capacitor C504 on the bottom of the board (see figure 2). If required, refer to the service manual board diagrams for details.
- Unsolder and remove the C504.
- Install and solder the .001 µF capacitor in place of C504.
- Assemble the transceiver be reversing the above steps.
 
This modification may be covered under warranty.
Time required for this modification is 1 hour or less.
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