MFJ-956 Modifications
Step-by-Step
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1. Disassemble: Remove the cover and two PC board bracket screws. Measure for two holes for the SPDT (center off) toggle switch, and the 5K Ohm pot. Securely mount the two new components.
2. Wiring: Solder three wires to the back of the PC board as shown: blue to the rotary switch wiper, violet to the capacitor input, and gray to the common bus for the coils.
(Note disregard jumpers on the board by the black arrow, as they were from past experimentation) Leave the wires at least 4-5 inches long. They will be trimmed during assembly.
3. Assembly: Follow the schematic, wire-by-wire, and connect the three switch wires and the three pot wires. Add the 470k Ohm bleeder resistor across the antenna input to ground. Test the assembly before closing the unit.

NOTES:
1. You may remove the logo and model number legends with a cloth dampened with lacquer thinner.
2. The 4:1 transformers shown in the schematic are optional. I elected to live with the simple modification first, for a while, to get a feel of its capabilities. Initial testing indicates that the transformers must be used to fully appreciate the utility of a preselector. Also, I may replace the coil for the .5-1.7 MHz position since it seems to have a Q value too low for its function.
(IMPORTANT: Please read the test results on the previous page.)
3. The Lengthen/Shorten function is most appreciated when using a wire antenna  that is shorter than one might like to have for the frequencies of concern. Likewise with an end fed antenna which is too long for the receiver. The L/S functions are very important when tuning high gain/low dynamic range receivers. This is very apparent with a radio like the Icom PCR-1000 or small portables.

It will become quite obvious that tuning the antenna circuit greatly increases the radio's performance-displaying its  full potential.

Hints: Use a 100-160 Watt soldering iron for the two SO-239 connectors and a 25-40 Watt iron for the PC board connections. Wires added should be 20-26 gage solid or stranded. Using the original wire colors will help to make assembly easier.
Added: 21 May 2006
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