As produced, the TS690S HF and 6m antenna sockets can be switched by the top mounted slide switch, but only when a 6m frequency is dialled up. This modification allows Tx and Rx on any frequency via the 6m skt, or, with the switch in the other position, to allow Rx on the HF skt and Tx on the 6m skt. Useful for those who use separate Tx and Rx antennas
1. How it works, unmodified. See Diagram: Filter Unit (X51-3100-XX)
- IC2, Pin 11 produces +12v, (via RFC L11) to energize Relay K17 which selects the 6m antenna socket, on Tx and Rx, but only when 6m is dialled up.
- On Transmit, +12v from connector CN6, Pin 6 energizes Relay K15, the Tx/Rx changeover relay.
This mod utilizes this same +12v on transmit to operate one or both relays dependant on the slide switch position.
2. Modification procedure.
- Remove top cover.
- Remove filter unit cover.
- Remove filter unit board.
- Locate and cut the earth connection on the Slide Switch (S1) Then, using a thin wire, join this switch connection to a permanent +12v supply. The 12v fuse holder is conveniently nearby.
- Then, locate L11, mounted vertically, near the slide switch. Carefully cut the wire coming down from the top of this RFC to the board, near the middle. This will allow re-connection should you wish to un-modify later. To the top end of L11, solder a wire and connect the other end to the rear end of RFC L12, (near to Relay K15)
Now in one position of the switch, +12v permanently energizes K17, selecting Tx and Rx on the 6m skt on any frequency.
With the switch in the other position, on Rx, the HF socket is in use, but on Tx, +12v from L12, energises relay K17 changing the Tx o/p onto the 6m skt, on any frequency.Put it all back everything back in the reverse order
Do try this. It is easy and, as your set is out of warranty, what have you got to lose ? A later mod introduced a 'centre off' slide switch. This allows Tx/Rx on the HF skt, Tx/Rx on the 6m skt and also automatic C/O from HF skt on Rx to 6m skt on Tx. As there were two sets of switch contacts, I used the other set to switch 2 LEDS in a small box bolted to the top cover, using a cover retaining screw, to show me which position the switch was in.?