FT41R.2

From: KA8WPC@KF8OW.#NWOH.OH.USA.NA

      THE FOLLOWING IS A MOD THAT WILL ELIMINATE A PL PROBLEM
   WITH THE YAESU FT41R PORTABLE.
    WORKING WITH YAESU, THE MOD WHICH CORRECTS THE PROBLEM OF
  PL ENCODE, WHEN IN TX MODE, IS NOT A TRUE PL.  WHAT THIS MEANS,
  IS THAT THE PL WAVEFORM IS SAWTOOTHING. ADDING MIC AUDIO, MAKES
  THE PROBLEM WORSE.  TRYING TO ACCESS A REPEATER IN DECODE, CAUSES
  THE SIGNAL TO DROP OUT OF THE REPEATER WHEN MIC AUDIO IS APPLIED.
  ALSO, IN COUNTING THE PL, EXAMPLE 103.5hz. GENERATES A PL FROM
  103.9-104.7.  ALSO THE MIC GAIN WAS SO HIGH, THAT AMBIENT NOISE
  WAS BAD.  SO, AFTER CALLS TO YAESU USA, AND YAESU JAPAN, THE MOD
  LISTED BELOW, STABILIZES THE PL, GIVES IT A SINE WAVE OUTPUT, AND
  LOWERS THE GAIN.
    NOTE: IF YOU ARE NOT FAMILIAR WITH SURFACE MOUNT TECHNOLOGY,
          BE EXTRA CAREFUL!

  THE BOARD NEEDED TO MODIFY IS THE AUDIO BOARD.
 REMOVE THE 4 BLACK SCREWS ON THE REAR OF THE RADIO.
 REMOVE THE 2 SILVER SCREWS ON THE BOTTOM OF THE BATTERY CASE.
 CAREFULLY SEPARATE THE FRONT/REAR HALVES.
 SET THE UNIT FRONT DOWN, AND REMOVE THE 2 BRASS SCREWS HOLDING THE
 AUDIO BOARD.  GENTLY PRY THE AUDIO BOARD FROM THE MICROPROCESSOR BOARD.
 TURN THE AUDIO BOARD OVER.  THIS IS THE SIDE THE MODS ARE DONE.
 ABOUT CENTER, ON THE HIGH SIDE, LOCATE Q3001. (14 PIN IC)
 JUST ABOVE AND TO THE LEFT OF PIN 1, IS LOCATED CAPACITOR C3005.
 IT SHOULD BE THE BIGGER OF ALL THE PARTS IN THE AREA.
 IT IS IN SERIES WITH PIN 14 OF Q3001 AND R3007.
 REMOVE THIS CAP. INSTALL A .047uf IN IT'S PLACE. (I USED A .039uf)
 INSTALL A 180K RESISTOR IN PARALLEL WITH R3001 (ACROSS Q3001 PINS 1&2)
 INSTALL A 56K RESISTOR IN PARALLEL WITH R3002 (ACROSS Q3001 PINS 13&14)
 WHEN DONE SLIGHT TWEAKING MAY NEED DONE WITH THE DEVIATION CONTROL.
 FOR APROX 5khz. OF MIC AUDIO WITH PL.
 IT IS LOCATED ON THE FRONT BOARD NEAR THE TOP.
 LOOK AT THE SCHEMATIC, AND YOU WILL SEE WHAT IS HAPPENING WITH THE MOD!
 THE CAPACITOR ADDITION IS CHANGING AN R/C CIRCUIT FOR TIMING OF THE PL.
 RESISTOR R3001 CONTROLS THE GAIN OF THE IDC AMP FOR TT AND MIC AUDIO.
 RESISTOR R3002 CONTROLS THE GAIN OF THE MIC AUDIO ONLY.
 AGAIN, DO THIS MOD ONLY IF YOU HAVE KNOWEDGE OF SURFACE MOUNT TECHNOLOGY!
 ALSO, I CLAIM NO RESPONSIBILITY FOR ANYONE DOING THIS MOD.
 THIS MOD WAS FOR ME FROM YAESU.  I SUGGEST THAT IF YOU ARE UNEASY ABOUT
 PERFORMING THIS MOD, CONTACT YOUR SERVICE TECH OR YAESU.

 OTHER THAN THE ABOVE PROBLEM, I OWN BOTH THE FT11R AND THE FT41R, AND
 I RECOMMEND EITHER OR BOTH TO ANYONE LOOKING FOR A SMALL SIZE POWERHOUSE
 HT, LOADED WITH ALL KINDS OF FEATURES!
                                              73, -=MIKE=-

 KA8WPC@KF8OW.NWOH.OH.USA.NA
 PHONE: (419) 666-8849