Locate the main PCB with jumpers on it. It is located behind the display board. Find Jumper J2. If you clip this jumper you will have 26.000MHz to 29.700MHz. If you place the Jumper on pins P1 and P2 you will have 26.000MHz to 32.000MHz. After "Jumping" your radio dont forget to press the CPU reset button located below J2.
Real easy to modify. There are a set of jumpers on the back side of the display board marked J1 and J2. One set has a jumper already on it . Remove this and put it on the two pins next to you and you will have 26.000MHz to 29.700MHz. If you jump both sets of pins you will have 26.000MHz to 32.000MHz. Thats all there is to it.
Before you "peak out" your radio its wise to change Q51 from a 2SB754 to a 2SB688 or 2SB817. The 2SB754 is a 60w, 7A power regulator. The 2SB688 is an 80w 8A and the 2SB817 is a 100w 12A regulator.
Most people remove Q32 which is a modulation limiter. It gives you more modulation on AM but it will "garble" badly on SSB. It also disables VR12 (SSB ALC) and variable power for SSB. I dont personally recommend this. There are 2 better ways to get greater modulation on both AM and SSB.
1/ Buy a quality Power mic. 2/ Locate R178 and change it to a 3K. Locate R194 and change it to a 4.7K. Locate R281 and change it to a 10k . Re-adjust VR14 (AMC) for maximum forward modulation. If you decide to use a power mic in the future you will have to change this modification back otherwise you will get bad overmodulation..... i think option 1 is the best
There are 2 ways of doing this mod. The first way will increase your "dead key" but will lose some of the swing. The second way is better as it allows the dead key to be lower. With a lower dead key it will allow more drive voltage available to the modulators which in turn are now driving the RF driver and Finals Transistors.
METHOD 1/ Place the radio with the display facing you, component side up. Toward the back left hand corner is a silver Alu board standing up vertically between 3 pins. Pull this board straight out. Solder a piece of 16 - 22 SWG wire from the middle pin to the positive power on the back side of the power cord. Then solder another piece of wire between the two outside pins. Next turn the RF power Knob all the way anti-clockwise and turn the CB on and set to AM mode. Transmit and set VR15 for 2 watts dead key. Then turn the power knob all the way clockwise and adjust VR13 for maximum dead key (about 12 to 15w). Now turn mode to LSB. Turn the power knob all the way anti-clockwise again then transmit and adjust VR16 (SSB low power ALC) for 5 to 6w PEP. Now turn the power knob all the way clockwise and whilst transmitting adjust VR12 (SSB high power ALC) for maximum swing. If you feel brave you can also tune cans L10, L13, L14, L34 and L46 in AM mode while transmitting for a few more extra watts. If you want a higher dead key on AM, parallel 330pf caps across C261, C262 and C270. This will get you closer to a 20w dead key.
METHOD 2/ To do this mod you will need a 1N914 diode and 50 ohm resistor. Locate Q51 which is the 2SB754 transistor. Hook it up as the drawing shows. This will give you super modulation at whatever power range you want. to be completed soon