President Jackson CB-Radio


Modification for AM, SSB and to get +5 kHz step


1: Unsolder wire from D74 and R150 to small PCB
2: Unsolder wire on rotary switch
3: Solder wire from R101 to JP32
4: Solder two track on small PCB


 


Modification for 240 channel


Soldering side:
1: Unsolder the white wire from point C
2: Unsolder the grey, brown, red, yellow, blue and white wires (they were all soldered together)
3: Each of them has to be soldered on its plase (exept the white one which is not necessery anymore and the gray that has another plase)

Components side:


Solder the gray wire onto the programming card, inside the small white circle.


To increase the power


1: Component side: on R227 replace the resistance of 100 ohm by another of 1,5 kohm.
2: Soldering side: get off the 1.5 kohm resistance from the adjustable resistance VR8.




Modification One band above and below standard


To go 1 band lower you would need to change the programming on the binary adders, this is quite easy to do, when you change bands you are actually changing the programming on the binary adders, to go down 1 band you will need to break the signal to the adders from the band switch, this will cause the radio to go down 67 channels below the band "A", to get the radio to be 1 band below band "A" you need to pull pins 4 and 2 high on IC6 and pin 6 high on IC7.

You MUST do this through some diodes other it will cause problems when using other bands.

I would suggest that you take the signal (about 8V) from the switch when in the A band, run it to a switch, which will allow the signal to pass to the binary adders as usual (for normal A band) or through the 3 diodes to the pins I mentioned above.

To go 1 band higher would be quite more tricky, this is because the binary adders can only increase the code by 8 channels from the E band, if this is enough just pull pin 15 of IC6 high (8V) this will make the radio increase by 8 channels on bands A,B and E.

OR a more complex method that will give the band you want would be to do a similar mod as for the 1 band down, use the E band signal through a switch to select either the original or a new set of diodes that will go to pin 2 of IC6 and pins 4, 2 and 15 if IC7, then you will also need to cut the track that goes to pin 11 of the PLL and pull the pin high (about 8V), this will give you an increase of 1 band above the E band, call it F if you like.

Frequency list

Ch.ABCDEF
0125.61526.06526.51526.96527.41527.865
0225.62526.07526.52526.97527.42527.875
0325.63526.08526.53526.98527.43527.885
0425.65526.10526.55527.00527.45527.905
0525.66526.11526.56527.01527.46527.915
0625.67526.12526.57527.02527.47527.925
0725.68526.13526.58527.03527.48527.935
0825.70526.15526.60527.05527.50527.955
0925.71526.16526.61527.06527.51527.965
1025.72526.17526.62527.07527.52527.975
1125.73526.18526.63527.08527.53527.985
1225.75526.20526.65527.10527.55528.005
1325.76526.21526.66527.11527.56528.015
1425.77526.22526.67527.12527.57528.025
1525.78526.23526.68527.13527.58528.035
1625.80526.25526.70527.15527.60528.055
1725.81526.26526.71527.16527.61528.065
1825.82526.27526.72527.17527.62528.075
1925.83526.28526.73527.18527.63528.085
2025.85526.30526.75527.20527.65528.105
2125.86526.31526.76527.21527.66528.115
2225.87526.32526.77527.22527.67528.125
2325.90526.35526.80527.25527.70528.155
2425.88526.33526.78527.23527.68528.135
2525.89526.34526.79527.24527.69528.145
2625.91526.36526.81527.26527.71528.165
2725.92526.37526.82527.27527.72528.175
2825.93526.38526.83527.28527.73528.185
2925.94526.39526.84527.29527.74528.195
3025.95526.40526.85527.30527.75528.205
3125.96526.41526.86527.31527.76528.215
3225.97526.42526.87527.32527.77528.225
3325.98526.43526.88527.33527.78528.235
3425.99526.44526.89527.34527.79528.245
3526.00526.45526.90527.35527.80528.255
3626.01526.46526.91527.36527.81528.265
3726.02526.47526.92527.37527.82528.275
3826.03526.48526.93527.38527.83528.285
3926.04526.49526.94527.39527.84528.295
4026.05526.50526.95527.40527.85528.305


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