Yaesu's classic, top of the line HF transceiver for contesters and DXers is
probably the only ham dual-receiver radio that does true diversity reception
|FT-1000D Synchro Mod by G3TKF|
Photo 1: My version of this mod is connectorized- added headers provide accessible solder points for connecting to the Ø1 and Ø2 encoder signals, +5V, and ground. The main and sub encoder plugs are pulled from their connectors on the Control board and reconnected through a simple wiring harness. The radio can be quickly restored to its original configuration by simply replugging connectors. The main encoder plug, visible at the right edge of the shield, connects directly to the board using a home-made right-angle adaptor. The sub encoder plug 'floats' outside the enclosure on the harness. Note the snug-fitting teflon sleeving over the solder joints on the floating header.
Photo 2: The relay shown is a low profile Omron G6A-234P-ST with sensitive coil. The body is about 0.325" (8.26mm) high. I also verified that standard size DIP relays about 0.450" (11.4mm) high will clear the cover. I used #26AWG solid wirewrap wire in colors consistent with the Yaesu harness. The yellow wire brings +5V over from one of the connectors (relay top left), and the gray wire comes from the SPOT switch (relay bottom left). These two wires were woven into the original harness bundle for added mechanical support. The diode and capacitor, not shown in this view, connect across the coil terminals on the left.
Photo 3: Relays, crystal filters, and other larger components usually need to be secured to a mounting surface in some way. Because I was in a hurry to try the circuit, I took a thin piece of foam packing material and pressed it onto the relay PCB leads. This made for a snug fit under the shield cover and locked the relay in place against the PCB. Care must be taken to insure that the exposed PCB terminals cannot contact the cover. If you think you might send your radio back to Yaesu for service in the future, a foam block might be a better method than double-stick foam tape. For this purpose, the foam material must be soft and easily compressible, not rigid like styrofoam. It should exert only a slight pressure against the cover and PCB. Note that the relay cannot be bonded to the inside of the shield because the mating cover has a flange that fits down inside the shield.
Pictorial 1: This is a view of the SW F PCB containing the SPOT switch, as seen when the front panel is hinged down. The "X" shows the approximate location where I made my track cut- actually it may be cut anywhere between the switch and the connector pad shown at bottom center. The solder point for the wire connecting to the relay coil is the round switch pad just below and to the right of the "X". This point grounds when the SPOT switch is on, energizing the relay and enabling 'synchro' mode. If a PCB track cut is unacceptable, a 'no holes' alternative might be to pull out connector P8805 and slip pin 3 (SPOT) out of the housing, insulate it, and bend the wire back out of the way.
Photo 4:The SW F board is visible in back of the Shift/Width control. Note the gray wire connected to the N.O. terminal of the SPOT switch. The track cut is visible to the left of the wire connection.
Relay, DPDT, 5V, Sensitive coil
Omron G6A-234P-ST (5V), Omron G6A-234P-ST-US (5V), NTE R40 series- Mouser P/N 526-R40-11D2-5/6, Aromat DS2E-S-DC5V (Try Digi-Key), or equivalent. Rcoil approx. 125 ohms or greater, Pcoil approx. 150-200mW (to minimize added load on the 78L05 regulator)
Header, 0.025" Square Post, Female, 4 Postion (need 2)
FCI "Dubox" 68685 series- Needs to be cut to length from longer connector and the end filed smooth- Mouser P/N 649-68685-3xx (substitute number of positions for "xx"- 06, 08, 10, 14, 16, 17, 18, or 20) Also need to file 45º bevels in two corners to fit connector shroud on Control PCB
Header, 0.025" Square Post, Male, 4 Position (need 2)
Circuit Assembly 36 pos. single-row, straight PC strip line plugs- Mouser P/N 544-CA-S36SP100 (Designed to be snapped apart into needed lengths)
Diode, Silicon, 1N4001 (or similar) Protects against transient voltage spike from relay turnoff. Install right at the relay coil.
Capacitor, 0.01 uF
Tywraps, White Plastic, 4" (optional) For cable lacing
Teflon Sleeving (or similar) For insulating solder tails on sub encoder header
Tape, Double-Stick, Foam (alternative: soft foam sheet)
Synchro Mod User Tips:|
Both the main and the sub receivers may be independently programmed for band, frequency, mode, and bandwidth while in Synchro mode. The two will continue to track at the same tuning rate. You can return instantly to Diversity mode at any time by punching A>B.
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