Modifications for the Yaesu FT-23

FT-23R power save off mods

Hi All, I would like to thank all who sent replys to my request for info in trying to disable the power saver circuit in the 23r. I use it for mobile and portable packet and have not had much luck in making it work unless the freq. would stay busy.
The mod is as follows. Take apart the 23R and look at the control board. There will be a bundle of wires tied together basically over pad #10.
It is marked, as 10. Soder a jumper across this pad or bridge with soder, put the radio back together.
You will find that the battery life is not near as long with out the saver circut. I would guess if you wanted to do some mode mod ification.
(Sorry Wasnt watching the line)
One could put in a very small switch and just disable it when needed.
I basically always use the battery eliminator so the battery life dosent bother me. Thanks again to all the help.


FT-23R extended frequency range

Modifying 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.

Instructions on modifying the Yaesu FT-23R 2M handheld radio for operation in the Civi Air Patrol service.

* * * * * * * * * * * * * * W A R N I N G * * * * * * * * * * * * * * *

This radio is NOT type accepted other to show Part 15 compliance. Operation in any service requiring the use of type accepted equipment is in violation of FCC regulations.
  1. Remove the 3 screws from the top of the radio.

  2. Remove the dial knob

  3. Remove the 2 screws from the back 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 of the radio.

  7. To the left of the microprocessor and battery are several printed circuit pads. The pair labeled 7 will have a blob of solder across them. Using a small soldering iron and solder wicking, remove the blob of solder.

  8. Re-assemble the radio in the reverse order of these steps.

  9. The Microprocessor will PROBABLY reset all the memory contents.

  10. Operation of the radio remains the same, except that the transmit and receive coverage will now extend from 140.000 Mhz to 164.000 MHZ.

************* ANOTHER MODIFICATION ************


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  in        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. Pressing F 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 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!

Extended frequency for FT-23,33, and 73

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
How to do it:
  1. 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.

  2. 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.

  3. Dissassemble your tranceiver.

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

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

  6. Rebuild radio and count your blessings.


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 , 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.

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.
Yaesu FT-23R 2m walkie talkie anthology

by Frank Reid, W9MKV1

As the happy owner of several Icom radios, I went to a hamfest intending to buy a new IC-u2AT but my friends talked me into a Yaesu FT-23R instead. I'm glad!

Construction: The case is die cast metal (u2AT is plastic) and is well protected against weather except as noted below (see DTMF). The carrying case is rather unattractive, made of odd smelling material; I don't trust its belt loop or Velcro flap closure. I removed the belt loop and cut a slit for the (optional) belt clip. I used a paper punch to round the ends of the slit to prevent tearing.

Human Engineering: Yaesu did an excellent job of making a complex radio easy to operate. I especially like the rotary knob which selects presettable channels (10) or tunes in 5 or 10 kHz steps. Six keyboard buttons (one is an alternate function key) control programming and scanning. UP/DOWN keys duplicate the knob's function, and have an alternate 1 MHz "giant step" capability.

The keyboard lock function does not affect the rotary switch. Keyboard lock (indicated by an "L" symbol on the display) is remembered when the radio is turned off (good idea!). The FT-23R has odd offset capability. A button above the transmit switch unsquelches the receiver (transmits tone burst on European model).

There is no display illuminator, which would be practical with knob tuning; display lights in keyboard controlled rigs are nearly useless when it's too dark to see the keyboard.

Not surprisingly, the tiny flat speaker isn't very loud, and rattles terribly at full volume. Speech from a belt mounted FT-23R is easily drowned out. It fits a shirt pocket, somewhat inconveniently with DTMF2 and large battery installed. It can be secured in a shirt pocket by hand lanyard attached to epaulet of military style shirt, or longer string with sliding cord lock, over the shoulder with loop around opposite armpit.

Standard BNC connector. The "short rubber duckie" supplied with the radio is more flexible than most similar antennas, and appears very durable.

The optional Touch ToneTM generator mounts between the radio and battery, plugs into a 4 pin internal socket, and is attached by 4 long screws. It makes the radio about 3/4 inch taller, and 1/8" thicker. Other accessories, e.g., the mobile power adapter, also mount between radio and battery; one envisions a future fully equipped wlakie-talkie 3 feet long!

The delicate looking membrane type DTMF keyboard is not sealed around the edges. There could be trouble if it takes water. The DTMF keyboard has neither tactile nor audio feedback, however, an LED lights when a button is successfully pressed.


3 The optional subaudible tone squelch module provides "PL" encode . Actual tone squelch frequency is displayed during programming (nice!). The tiny module ($61) mounts above the battery attachment plate, and does not extend the radio's length. CTCSS modes are "Encode" and "Encode/Decode" but no decode without encode.

Memory Cloning: A cable from the earphone jack of one FT-23R to the microphone jack of another transfers memory contents (useful for emergencies). A switch on the bottom of the radio (accessible by removing the battery) puts the radio into clone mode. You cannot reach the clone switch if the DTMF module is installed.

The FT-23R has CHANNEL-SCAN (all 10, with lockout), PRIORITY SCAN (checks ch. 1 every 4 seconds) and BAND SCAN (no presettable limits). There is no timeout resume scan mode. Scan rate is 2 preset channels per second. Band scan is much faster; 1 MHz in 9 seconds @ 10 kHz/step, 18 sec @ 5 kHz/step. I encountered NO "BIRDIES" (spurious receiver responses) during 140-164 MHz band scan, with a shielded 50 ohm dummy antenna.

Instructions: Well written in good English, but the book contains NO schematic or block diagram (Boo!). The receiver first IF is 10.7 MHz (not listed in specifications). Being careful not to transmit, I connected the antenna jack to a spectrum analyzer and found a -6 dBm (75 ohms) local oscillator signal 10.7 MHz below the receiving frequency. The spectrum analyser revealed a unique signature: the FT-23R's battery saver feature turns the receiver off (for 600 ms) and on (300 ms), in a cycle beginning a few seconds after the receiver is squelched (and not scanning). I have observed no bursts of TVI when the PLL relocks. Knowing the IF allows using the image response trick to listen to ATC while at airports. (Multiply first i.f. by 2, add to the desired aircraft frequency, tune the radio to the sum; AM comes through weak but readable.) I tried it at the local airport; the Yaesu's FM detector does not perform nearly as well on AM as does the Icom IC-02AT or IC-28H.

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. Too bad it won't do National Park frequencies.

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.

Receiver drain is 19 mA in power save mode. The FT-23R operates at any voltage from 6 to 15v. Three rechargeable battery options offer small size, long duration, or high power. Rated output at 7.2 v is 2.5 watts; a friend's rig and my own both produce 3.5 w with FNB-10 (7.2 v, 600 mAH) battery packs. Two replaceable cell battery packs are available (six AAA and six AA). Alkaline cells are invaluable for emergency service; AA cells are more cost-effective than AAA's. The three NiCd battery packs require three different wall-charger types (15-hour charge time). The optional automatic fast charger charges any NiCd pack in 5 hours.

Speaker Microphone: One is available from Yaesu. The Icom speaker-microphone works with Yaesu transceivers if a resistor inside the spkr-mic is replaced with a lower value, and It still works with Icom radios afterward.

My FT-23R, with DTMF and 7.2 volt 600 mAH battery, was $249 from some nice folks from Kansas City who didn't soak me for sales tax, at least overtly.

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