TS-940S's in the serial number range of 601XXXX through 708XXXX may be limited n SSB peak power as compared to full CW output. The level may be increased by changing the value of capacitors C182 and C183 in the ALC circuit on the Control board. The recommended replacement value for each capacitor is 0.0022 uF, 50v (CK45B1H222K).
Procedure:
- Disconnect the power cord and antenna from the transceiver.
- Remove the top and bottom covers (16 screws).
- Locate the Control board on the bottom of the transceiver.
- Locate transistor Q37 on the board (toward the back right hand side.) The two capacitors are mounted on the foil side of the board underneath Q37.
- To access the bottom of the board remove the 8 screws that mount the board and heat sink to the chassis (See figure 1.)
- Carefully lift the board/heat sink fomr the right hand side and pivot it toward the front of the transceiver.
- Replace C182 and C183 with 0.0022 uf, 50v capacitors.
- Lower the board back into its original position (don't pinch any wires!) and re-install the 8 mounting screws.
- Put the covers back on the TS-940S and secure them with the 16 case screws.
- Connect the antenna and power cord then test the transceiver for normal operation.
This is an optional change and may not be performed under warranty.
Time required for this change is 1 hour or less.
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