These were from my notes from long ago, last time I had a SS-3900GHP back in the late 90's:
SUPERSTAR 3900GHP MODS (ALSO WORKS ON SS1700, SS3600, SS3900, & OSAKA G-139)
VR POTS:
VR1 = AM/FM S-METER ADJUST
VR2 = SSB/CW S METER ADJUST
VR3 = SSB SQUELCH RANGE
VR4 = AM SQUELCH RANGE
VR5 = FM DEVIATION ADJUST
VR7 = CARRIER BALANCE ADJUST
VR8 = RF METER ADJUST
VR10= FINAL BIAS ADJUST
VR11= DRIVER BIAS ADJUST
VR12= ALC
VR13= AM POWER
VR14= AMC
VR16= CW MON ADJUST
VR21= TX FREQUENCY ADJUST
AM MODULATION LIMITER = TR32 (REMOVING DISABLES VR12 ALC ALSO, SO SSB PWR WILL BE AT FULL BLAST) USE R249 INSTEAD. THIS DISABLES AMC ONLY, NOT ALC.
POWER TWEAK:
1. REPLACE R174 (10K) WITH 1K
2. REPLACE R187 (10K) WITH 1K
3. ADJUST VR14 FOR MAX MODULATION
4. ADJUST VR12 FOR MAX SSB POWER, AND LOWER DOWN TO 25-35W PEP
5. ADJUST VR13 FOR MAX AM POWER WITH UPWARD SWING
6. TUNE L40, L43, L44, AND L33 FOR MAXIMUM FWD SWING ON WATTMETER
7. ADJUST AM POWER FOR NO MORE THAN 5 WATTS DEAD KEY. IF RUNNING A LINEAR, SET AT 3 WATTS DEAD KEY.
SUPERSWING:
1. Locate and remove R238 (Typically a 5.5K ohm resistor)
2. Install a 47 ohm resistor in series with a 1N914 diode, banded end down to the right)
TALKBACK:
FOR TALKBACK, REMOVE D80
ROGER BEEP:
TO REMOVE ROGER BEEP, REMOVE C134 (2.2MFD 50VDC.) TO ROGER BEEP DURATION, LOWER CAPACITANCE (i.e.: 1.0 MFD)
CHANNELS: (JUST LIKE DX88HML/DX77)
1. REMOVE TOP COVER AND REMOVE RED WIRE AND SOLDER BRIDGES. THIS GIVES 6 BANDS OF 40 CHANNELS, WITH BAND “D” BEING THE CB BAND
TO REACTIVATE HAM BANDS PERFORM THE FOLLOWING:
1. FIND IC7 NEAR 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 #14
5. THAT’S IT. IT GIVES THE 10 METER HAM BAND ON “E” & “F” (NOTE: SOME WEBSITES REPORT THAT THIS MOD SHOULD BE PERFORMED BETWEEN PINS 12&13... IT DIDN’T WORK LIKE THAT FOR ME!)
+10KHZ JUMP SWITCH:
1. GET A SPST SWITCH AND MOUNT IT IN THE RADIO
2. FIND IC6 & IC& NEAR THE PLL CHIP. THERE, YOU WILL SEE J68 & J69
3. SOLDER A WIRE FROM ON 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 (NEAR VR15) AND R135 (33K) 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 8 VDC SOURCE, LIKE THE COLLECTOR OF TR41.
4. TAKE THE YELLOW WIRE AND CUT IT FROM THE KNOB. TAPE THIS WIRE BECAUSE IT’S NOT NEEDED
5. THIS SHOULD MAKE THE RADIO TX/RX ON THE SAME FREQUENCY.
