President Jackson Extra Channels
1)Locate IC-7 and IC-5.(There near the PLL chip)
2)Found them??...Good! Lets start with IC-7
3)Cut the trace going to PIN #2.
4)With a SPST switch (We'll call this switch 1) solder both sides of the cut trace to each leg of
5)Now on IC-5 cut the trace going to PIN #12.
6)With another SPST switch (We'll call this switch 2) solder both sides of the cut trace to each
leg of the switch.
7)Now mount the 2 switches somewhere in the radio.
If all is done right SWITCH 1 will give you:
25.425 - 25.865 MHZ on channels 1 to 40 on Band 'A'
25.875 - 26.045 MHZ on channels 1 to 15 on Band 'B'
Then you can use SWITCH 2 with SWITCH 1
25.295 - 25.415 MHZ on channels 16 to 27.on band 'A'
The other 'Bands' are not affected with this mod.
1)Find the 14.550 MHZ crystal in the radio.
2)You can change this crystal to 15.450 and get 26.965 - 29.185 MHZ.
3)You can change this crystal to 15.000 and get 26.515 - 28.745 MHZ.
(By +/- .450 MHZ to the crystal you can move up/down a full band.)
President Jackson Clarifier mod
NOTE: You will be working on the 'Fine'clarifier control
2)Find the BROWN wire from the clarifier knob and cut it just before it connects to the P.C.B.
3)Solder this wire to 8 VDC.
HINT:You can find 8 volts at the 2 holes in the PCB at the front edge.
4)Find the WHITE wire from the clarifier knob and cut it just before it connects to the P.C.B.
5)Solder a 470 OHM resistor to the and then solder the resistor to GROUND
If all is right you should have +/- 2.2 kc of slide.
President Jackson 'PEAKs & TWEAKs'
MODULATION - Cut TR-41
AM POWER - ????
SSB POWER - Cut TR-37
AGC Modification for SSB
1)Change R-43 (10k ohms) to 1k ohm.
2)Change R-41 (150 ohms) to 270 ohms.
3)Change R-47 (1.50kohms) to 3.9k ohms.
4)Remove capacitor C-31.
Now strong SSB signals should be clear and not distorted.
Roger Beep delay
1)Remove R-168 (47k ohms) and install a 56k ohm.
2)Solder a wire from PIN 1 of IC UPC-1242H (audio chip) to PIN 2 of the mic socket.
3)IF...the talk back is to loud then install a 100 -500 ohm resistor in series to the mic socket.
4)IF...the receive audio drops then install a .01 uF ceramic disk capacitor in series to the mic