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Modifications SuperStar 3900

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+ 10 KHz Jump Switch



1)Get a SPST switch and mount it in the radio.
2)Find IC 6 & 7 by the PLL chip. You will see J68 and J 69
3)Solder a wire from one side of the switch to J68.
4)Solder a wire from the other side of the switch to J69.
5)That's it .Flip the switch to jump up one channel.

Open Clarifier

1)Find D75 and R135 and cut one end of them.
2)On the back of the clarifier knob follow the green wire to the
PC board. Cut this wire from the PC board.
3)Now Solder this wire to a constant 8VDC source, like the
collector of TR41.
4)Take the yellow wire and cut it from the knob. Tape this wire
it is not needed.
4)This should make the radio TX/RX on the same frequency.

10 Meter Mod

1)Find IC7 ny the PLL chip.
2)Get a SPST switch and mount it in the radio.
3)Solder a wire from one side of the switch to Pin #13.
4)Solder a wire from the other side of the switch to Pin #12.
5)That's it .Put the radio on 'Band D' then flip the switch to
jump up to 28.300 to 28.500.

Tweak and peak

Audio Limiter - Cut R249
AM Power - VR13
SSB Power - VR12