>From the Bench of: KB2Jpd

======================================================================
Extended Frequency Enhancements for the Yaesu FT-23R(2M), FT-33R(220), 
                    and FT-73R(70cm). (Revised)
======================================================================

Greetings and hello radio amateur operators. 

The topic is increasing the functional frequency coverage 
of what has been probably Yaesu's most popular handheld tranceivers.

To save manufacturing costs, Yaesu engineers designed multiple 
personalities in the same CPU module found in the FT-23R, FT-33R,UHF FT-73R 
and the FT-2008/7008 tranceiver. The FT-2008/7008 tranceiver is the commercial 
version of the Ft-x3R series. 

Unique features of this mod include 

-the just say Mao feature (**) 
(NO FREQUENCY READOUT: Ch 1 thru Ch 9 appear  on your display.
Great when you aren't looking and some fellow ham tries to rip 
off your simplex frequency) 

-the GREAT WHOPPER
(opens the CPU to 50-300 Mhz or 220-550 Mhz coverage. Full 
(.100 Mhz to 999.9995 Mhz) adjustable freq coverage available 
so far only on the FT-33R;this doesn't mean you can actually 
transmit but the Activity light goes in TX and you get a good 
fake RF bargraph that indicates that you can transmit on 750 MHz.
HOW TO DO IT:

0. Contemplate invalidating your warranty. No beginners beyond this
   point. If you don't know how to solder, don't learn here. Ask
   an elmer to assist.

1. If you treasure your memories, write out your contents of your radio
   on a piece of paper. When you make the changes, the CPU runs a small
   diagnostic and see that the jumpers have been changed. It will ERASE
   ALL PRIOR SETTINGS.

2. Dissassemble your tranceiver.

3. Find the line of solder connections running down the CPU board.
   GENTLY move all wires aside so you won't melt them.

4. Using solder wick and a Good low-power soldering Iron,
   see chart. Read special notes for the FT-33R.

5. Rebuild radio and count your blessings.

(**)NO FREQUENCY READOUT
------------------------
Removal of the solder bridge labeled number nine will
activate the commercial side of the CPU module. To flip to
the amateur mode, you would press F UP Arrow. To flip to
the commercial mode, you would press F Down Arrow. 

+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
+=+=+=+=+=+=+=+=+=+=+= FT-23, FT-73R Chart =+=+=+=+=+=+=+=+=+=+=+=+=

   50 to 300 Mhz spread        220 to 550 Mhz spread
   --------------------        ---------------------

   Open bridges 8,9  		Open bridges 7,8,9

+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
+=+=+=+=+=+=+=+=+=+=+=FT-33R Chart =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=

Same chart as above, but I wanted to add my experience of the Yaesu
FT-33R 220 Mhz radio. 
   When I removed number 7 and then did a cold reset   <see below>, 
the CPU cleared and showed me a L and a freq. I put .100 in. 
Press D/MR. Then a U appeared. I turned the VFo knob until 999.999 
appeared. Press D/MR. 

I also had to reenter the Repeater Split to the proper value.

On the VFO, I could QSY down to those limits (using F UP/DN) and 
listen to my local Channel 13 on 215.720/.660. 

Yes, 216-220 Mhz is available with this mod.  Great if 216-220
is the next 220 subband.

+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
-NOTES-NOTES-NOTES-NOTES-NOTES-NOTES-NOTES-NOTES-NOTES-NOTES-NOTES-
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=

<1> Cold Reset of the CPU Board.

With the radio upright and your nose pointing at the CPU board,
look at the Lower Right Corner of the CPU chip. You will see two
parallel SMT resistors. Below them is a screw with possibly a paper washer.
To the right is a SMT device (it's a cap) with a pointed end facing Left. 
Ground that point to the screw or to the case with a flat screwdriver. 
Awhile doing that, cycle on/off the radio to ensure a good reset. 
Remove screwdriver and then reassemble radio.

Dedicated to:
 -----  the knuckleheads in Barry Electronics who said it was impossible.
 -----  Yaesu Tech Support who claimed that there are no RESET circuits
        in their radios, when their schematic diagrams say otherwise.

Special Thanks to:

Ken, N2MUK, for playing the guinea pig.
Bobbie, KB2IFJ, for playing surgeon when I told him not to.

Please don't play with matches.
W2Fwd.NY.USA.NA

----------------------


YAESU FT-23R case disassembly:
------------------------------

1)  Remove the black screws from the top panel of the radio.
2)  Remove the knobs.
3)  Remove the black screws from the rear panel of the radio.
4)  Remove the battery.
5)  Remove the 6 screws on the bottom of the radio, where the battery attaches.
6)  CAREFULLY remove the front panel of the radio.
7)  In the left of the microprocessor and battery are several printed circuit
    jumpers. The jumpers labeled 7, 8 and 9 are for the frequencie mods, like
    explained in the following.
8)  Re-assemble the radio in the reverse order of these steps.  
9)  The Microprocessor will loose all what the memory contains.




YAESU FT211/23/73 band mods:
----------------------------

     The uP's in the FT-23R and the FT-211R/H can be set for several
     frequency and memory mode combinations. These modes are contorlled
     by the jumpers (solder pads) marked 7,8 and 9 on the processor
     board of either radio. Here's a list of what can be done:

       JUMPER         CONFIG     DISPLAY MODE
    7    8    9       NUMBER

   open open  in        1        140 to 164 MHz, amateur mode
   open  in   in        2        140 to 160 MHZ, amateur mode
    in  open  in        3        144 to 148 MHz, amateur mode
    in   in   in        4        144 to 146 MHz, amateur mode
   open open open       5        220 to 550 MHz, commercial mode
   open  in  open       6        440 to 450 MHz, amateur mode
    in  open open       7        50 to 300 MHz,  commercial mode
    in   in  open       8        430 to 440 MHz, amateur mode

     Both of my radios (USA) were shipped from the factory in config #3..
     They can be converted to config #1 without re-tuning just by changing
     the jumpers. Tuning range can be further expanded by changing to
     jumper config #7. The FT-211 has separate VCO's for transmit and receive
     and will lock over about 38 MHz from approx. 130 to 180 MHz. The FT-23
     has only one VCO and the overlapping lock range (Xmt & Rcv) is about
     25 MHz from approx. 135 to 175 MHz. Don't forget, if you adjust the
     VCO you must re-align every electronically tuned stage in the front
     end of the radio. The transmitters can be tuned for somewhat higher
     power output above 164 MHz but at a great power loss at 2m..
     The commercial memory mode will cause these functional changes:

     1.When in the MR mode, the channel number will be displayed instead
       of frequency. You can toggle back to the original "amateur" mode
       display by pressing F<up-arrow>. Pressing F<down arrow> takes you
       back to commercial mode. However, when switching from D to MR, the
       display will always revert to the commercial mode..
     2.The function of the Dot <Pri> button will be exactly reversed. That
       means now you can press just one button (Dot) to get into or out
       of the Primary function. The Pri funtion (in memory mode) will
       be indicated by a large "P" on the left side of the display..
     3.The only indication of low power operation is in the memory mode..
       A "C" will appear in the upper left corner of the display (where
       the primary "P" used to be). The bargraph will always read 100%..
     4.The band scan is now even more useless. The uP will painfully
       count from 50 to 300 MHz.

     I have been able to modify my FT-211RH to scan at about 10 chan/sec
     by speeding up the uP clock. This also speeds up every other uP
     function by x5, so you have to be fast on the "F" key. No squelch
     sensitivity or synthesizer lock-up problems have been encountered
     with this modification while scanning..
     Basically, I replaced the 800 KHz ceramic resonater (pn CSB800K)
     with a Radio Shack 3.58 MHz color burst crystal. The resonater is
     located on a small (2.5 sq cm) sub-board that is stuck with double
     sided tape to the radio's processer board. This sub-board is actually
     an outboard clock for the uP. The schematic I got with the radio
     showed the uP's internal osc. being used - so I don't know if my
     version differs from newer radios. This mod works fine untill you
     turn the radio off and then back on again. A startup glitch then wipes
     out all of the memories. To delay the oscillator start up, I added a
     220uF 10V electrolytic cap between the red wire on the sub-board
     and ground. Positive goes to the red wire. A convenient ground is the
     bare wire located diagonally across from the red wire (on the sub-bd)..
     So far I have been unsuccessful with this mod on the FT-23R H-T..
     Since  it uses the uP's on board osc, there seems to be no way to
     delay it's startup. Every time you turn on the power the uP resets..
     If  anyone can solve this problem I would be very interested in
     hearing from you!

     These are not intended to be step by step instructions. Also, you
     will want to have a service manual before you begin. If you're not
     familiar around surface mount components you may want to "learn"
     on something with cheaper consequences. Finally, don't adjust the
     VCO's unless you are familiar with how a synthesized radio
     works. Use your own judgement!

The mods also worked the same way on my FT-73, therefore I can't get it
to work from 430-450 MHz, unfortunately..

Hans
W4/DG3SAJ @ WB4TEM.#BCRFL.FL.USA.NA


----------------------

Date:     Wed, 18 May 88 10:25 EST
From: <REID@IUBACS.BITNET>
To: MBRAMWEL@BUSINESS.UWO.CDN


Subject: YAESU FT-23R EXTENDED FREQUENCY RANGE:

"Circumcising" the FT-23R is remarkably simple.  Removing one solder
blob (pad #7, clearly marked, 10 o'clock position from the speaker, 9
o'clock from the microprocessor) lets the radio receive and transmit
from 140.0 to 163.995 MHz. The two circuit boards with surface-mount
components are uncluttered.  When opening the radio, be careful not to
lose the tiny coil-spring inside the battery-release button.  I
haven't measured receiver sensitivity, nor do I know about performance
in big-city RFI; the FT-23R is considerably more sensitive at 162-MHz
weather frequencies than is my modified Icom IC-02AT.
[source: W9MKV]

 
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