MODIFICATION COLLECTION FOR THE KENWOOD TM-741A TRI-BANDER ========================================================== TM-741A/E FREQUENCY EXTENSION ============================= Phase 1 ------- a) Slide the release knob on the front panel to the right and remove the panel (be careful with the cable between the panel and the main unit.) b) Cut the green wire located in the left side (tape the bare ends of the wire to prevent shorts.) c) Switch the power on (a melody sounds to confirm the change.) Phase 2 ------- a) Unplug the connectors of the cable between the panel and the main unit. b) Remove the two screws on the rear of the panel and open the rear of the case. c) On the left side of the lithium battery there are four jumpers marked R54, R55, R56 and R57 corresponding respectively to b0, b1, b2 and b3 bits described below. Set the four bits as required for your country: - European Countries: mode $05 b3 = 0 b2 = 1 b1 = 0 b0 = 1 - USA, Canada and Asia: mode $03 b3 = 0 b2 = 0 b1 = 1 b0 = 1 WARNING: 0 => jumper set, 1 => no jumper. d) Refit the rear of the case by reversing the order of disassembly. Frequency range after modification ---------------------------------- |--------------------------------------------------------------| | || rx range || tx range || SHIFT | | unit || min | max || min | max || EUROPE | USA CAN ASIA | |------||------------------------||----------------------------| | 28 || 18 | 54 || 26 | 45 || +/- 100 KHz | iden | | 50 || 40 | 90 || 46 | 76 || +/- 1 MHz | iden | | 144 || 118 | 174 || 136 | 174 || +/- 600 KHz | iden | | 220 || 215 | 260 || 215 | 235 || +/- 1.6 MHz | iden | | 430 || 410 | 470 || 410 | 470 || +/-1.6,-7.6 | +/- 5 MHz | | 1200 ||1100 |1400 ||1100 |1400 || +35, -6 MHz | +/-12,-20MHz | |--------------------------------------------------------------| TM-741A/E AM RECEPTION WITH 28 AND 50 MHZ UNIT ============================================== a) Press the [F] key, then press [BELL] key within ten seconds. An A is displayed at the hundred-MHz position to indicate AM mode. b) To return to FM mode press the [F] again, then press the [BELL] within ten seconds. TM-741A/E 900 MHz BAND RECEPTION WITH 430 MHZ UNIT ================================================== Band change ----------- To change to the 900-MHz band, select the 430-MHz band, then press and hold down the [MHZ] key for at least a second. Now 850.000 (initial setting) is displayed. To return to the 430-MHz band, press the [MHz] key again for at least a second. Adding a secondary 900-MHz dedicated antenna in the 430-MHZ unit ---------------------------------------------------------------- a) Remove the power supply cable from the power supply or battery. b) Remove the 430-MHz band unit with care. For removal procedure see the INSTRUCTION MANUAL - UNIT INSTALLATION, reversing the order of the procedure and... using the brain! c) Remove the shield plate (12 screws.) d) Solder a coaxial cable (0.8 D) to the input side of IC9 (center is alligned with the IC9, ground at right side.) e) Pass the cable throungh the notch and install the shield plate. f) Reassemble the main unit. TM-741A/E MEMORY CHANNEL DOUBLING ================================= Each band can be switched to the normal memory (100 channels) and rear memory (100 channels). Each band can contain 200 channels and... yes, a total of 600 channels can be used for three bands! SORRY! This function can be enabled only by extending the receive frequency (see bulletin #1 of this FREQUENCYEXTENSIONSNEVERENDHISTORY.) To switch the memory, hold down the [F] key and press the [REV] key: Normal Memory (100 ch) <--> Rear Memory (100 ch) The functions of the rear memory are the same as the normal memory, but memory channels are displayed as follows (rather than 01 to 00): A1 - b0 == 01 - 10 b1 - c0 == 11 - 20 c1 - d0 == 21 - 30 d1 - E0 == 31 - 40 E1 - F0 == 41 - 50 F1 - G0 == 51 - 60 G1 - h0 == 61 - 70 h1 - i0 == 71 - 80 i1 - J0 == 81 - 90 J1 - AA == 91 -100 TM-741A/E EXTENDED PAGING FUNCTIONS =================================== Preliminary ----------- Cut the frequency extension jumper as described in Phase 1 of the bulletin #1. Answerback function ------------------- Hidden function of the paging function. If the answerback function is on, the code of the local transceiver is automatically transmitted to the other transceiver when the correct code is received to confirm the code has been received. OPERATION After the correct code is received, if there is no BUSY signal, the code of the local transceiver is automatically transmitted to the other transceiver. ON/OFF To turn the answer-back on and off, hold down the [F] key and press then the [CALL] key. Automatic release function -------------------------- Hidden function of the paging function. OPERATION If the automatic release function is on, paging is terminated automatically when transmission ends after a call is received. ON/OFF To turn the function on and off, hold down the [F] key and press then the [SHIFT] key. TM-741A/E DATE DISPLAY FORMAT ============================= The normal date format is YEAR-MONTH-DAY. It can be changed to YEAR-DAY-MONTH. a) Remove the front panel and locate R60 and R61. b) Move R61 (that is below R60) to the left. c) Repack the front panel with care. TM-741A/E DC POWER DISPLAY ========================== Make the following change to display the SB line voltage on the memory channel section when the time is displayed. a) Remove the front panel and locate R60 and R61. b) Move R60 (that is above R61) to the left. c) Repack the front panel with care. Since the voltage of the SB line to the panel is displayed, it changes due to the loss caused by the wire and connector. TM-741A/E HEADLIGHT LINKAGE DIMMER ================================== Make the following change to reduce the dimmer level by one step when the headlight is turned on (d4 remain unchanged). a) Install DTC144EK on the panel printed circuit board (below R60 and R61). b) Connect the load from the ILUMI pin of the panel printed circuit board to the 12 V side (where 12 V is output when the light is turned on) of the position light of the car. TM-741A/E GAME MODE =================== Simple games, such as a roulette game and a shooting game, and music can be played using the frequency display. To enter game mode, hold down the [F] key and the [MUTE] key, and switch the power on. 1-2-3 is shown on the display. [BAND SEL A] selects Roulette, [BAND SEL B] selects Shooting, and [BAND SEL C] selects Music. To return to game selection mode, press the [VFO] key. To exit game mode, press the microphone key or switch power off. Roulette Game ------------- * When the roulette game starts, the display shows [000], the transceiver enters the receive mode with the power on, and the three digits begin to run rapidly. * When the [MUTE] key is pressed, [000] on the display can be changed: [BAND SEL A] stop the leftmost digit, [BAND SEL B] stops the middle digit, and [BAND SEL C] stops the rightmost digit. Other keys are not accepted. * if the three digits match, the LED and illumination lamp flash and sound effects are produced. * if [123] is displayed, a fanfare sounds. If the [MUTE] key is pressed, game mode is exited and the transceiver functions normally. Shooting game ------------- * When the shooting game starts, your score is shown in display section A, and cannon balls, target and remaining cannons are shown in display section C, strating from the left. * If the [LOW] key is pressed, the game starts. The "number" attacks from the left of display B. Take aim at the enemy "number" with the [TONE] key key, and shoot with the [MUTE] key. You win if 16 enemies are shot per screen. Thirty cannon balls can be used per screen. Each time you clear a screen, the speed increases. If eight screens are cleared, the first screen returns. The process is repeated. Music ----- When the music feature is selected, [ENJOY SOUND PLAY] is displayed and the following tones can be produced: MR = A MUTE = F MHz = A# CSEL A = F# CALL = B BSEL A = G F = C CSEL B = G# BELL = C# BSEL B = A TONE = D CSEL C = A# REV = D# BSEL C = B DTSS = E DISPLAY TEST Hold down F and MHZ while turning on power. This activates the display test mode where all segments and indicators are lit. Note the "ACC" indicator at the lower right. ACC is not defined in the manual, however I saw it come on once one night after I started the car with the radio turned on. The display lit up ACC and the UHF frequency display showed some sort of HEX code (a ROM checksum maybe?). STRANGE TEST (WARNING: YOU MAY LOSE SOME SAVED MEMORY DATA) Hold down the F and MR keys while turning on power. The radio plays a wild sequence of tones and the displays go all crazy for several seconds. When it's done, everything seems normal except that the memory contents are reshuffled and some memories are duplicated. I can only speculate that this might be some sort of factory memory test... --------------------------------------------------------------------- UNDOCUMENTED TM-732A FEATURES CLONE MODE Hold down the F and MHZ keys while turning on power. The current control band will display CLonE. Pressing CALL initiates the data transfer, graphically illustrated by a moving S-METER display. No RF is transmitted during data transfer, instead it is assumed that the data is dumped out of the microphone port. Nothing more is known about this at this time. AM DETECTOR CONTROL The AM Detctor, which automatically comes on below 136 MHz, can be forced ON at any VHF frequency by pressing the F and MUTE keys while applying power. Radio continues to transmit FM but receives AM. Changing frequencies or memory channels will cancel the forced AM mode. This capability could be useful for listening to the USAF Thunderbirds which sometimes operate in the 143 MHZ band using AM. These are all of the mods that I currently have (I think). If anyone has any corrections or additions to this list, please let me know. I'd like to put together as complete a list of the mods for the TM-741 as I possibly can.... Also, I've seen several references to the TM-732. Is this the same radio (as far as being able to do mods) as the TM-741? I can't seem to find any kind of a good description for the 732. Does anyone know of any mods for the 732 that will NOT work for the 741? Thanks, -- Monte Freeman -- Operations Department / Information Technology Georgia Institute of Technology, Atlanta Georgia, 30332 Internet: ccoprfm@prism.gatech.edu Bitnet: ccoprfm@gitvm1.bitnet