Subject: HF, VHF, UHF MODIFICATIONS FOR ALLMOST EVERYTHING Keywords: PRINT THIS OUT, LOTS OF GOOD INFO. -=-=-=-=-=-=-=-=-=- I decided to leave this file in one piece and not to spilt it up into individual files, so appologies for those mods that have been duplicated elsewhere on the Mods Disks. BOB G0LBQ - N6XDI. -=-=-=-=-=-=-=-=-=- These are mods I've been saving off the system for a while. People keep asking for some of the same mods. Here are all of the mods and text that have been published, giving sources credit where I was able. If any of these mods are helpful to you, please send me any mods that you may have and don't see here. (Send to me also, BOB G0LBQ) Thanks to everyone that helped me with this. Enjoy! Ed Thomas, N2IHN. Mods for: 735,720,745,751,430,940,440,2600 ht ICOM IC-735 To unlock the transmitter: cut diodes D33 and D34 that are standing on end near the microprocessor section toward the rear top of the radio. ICOM IC-720 Transmitter is unlocked by snipping the light blue wire that's at the very end of the top hatch cover to the left middle side of the transceiver. ICOM IC-745 Locate the RF board on the side of the radio and cut the light brown wire at jack 7., which is going to pin 1. Your transmitter is now unlocked. ICOM IC-751 Locate the RF board on the side of the radio and cut the black wire going to pin 1 of jack 2. Your transmitter is now unlocked. (This mod also described in _73_, July 1985 p. 12.) KENWOOD 2600 Locate the two diodes standing on end with Teflon covering the top part of their leads (which at one time were soldered together, broken, and then resoldered). Simply clip these two leads to unlock the transmitter, but be sure to reset the microprocessor by pushing the reset button before the set is capable of transmitting on any frequency at 150 MHz. KENWOOD TS-430S Unplug 3-wire plug on the RF board that mates with socket 10. When looking at the top front of the radio, it's to the left front side right beside a larger white plug. You'll need to carefully examine the circuit board and locate the number 10 with a circle around it to insure you have the right plug. ( See main file for other Mods - BOB G0LBQ) KENWOOD 940 Locate IC number 109. Now find diode 130 and cut it for all-band transmit. If you want just MARS coverage, locate IC 111 and 112, and snip diode 135 beside it. KENWOOD TS-440 1. Remove 17 screws holding on the bottom and top covers. The bottom cover comes off, and the top cover is carefully removed and put next to the radio. It is till connected via the speaker wire. 2. Gain access to the front of the unit by removing two top side screws and loosening two bottom side screws. This allows the front assembly to swing open. 3. Remove the shiny silver control board protection plate. This requires removing two screws on the top and three screws on the bottom. Lift the plate out completely. 4. Locate diode D-80 in the bottom left-hand corner. Snip it for all-band transmit. 5. Now locate D-66 and snip. It adds 10 Hertz readout to your digital frequency display. 6. Carefully reassemble the control plate using a magnetized tiny screwdriver to hold the five tiny screws in place. Don't pinch any wires. Also, close up the front and replace the top and bottom covers with 17 screws. 7. Connect power. Depress A=B switch and turn on the power simultaneously. This resets the microprocessor for all-band transmit and 10 Hz frequency display. IC M-700, 757GX MODS: ED THOMAS, N2IHN YAESU 757GX Lert,Peter: "Bootleg HF Radios," _IFR_ magazine, Premiere issue, 1985, p. 12. Open the radio and flip an unmarked but quite accessible switch.  ICOM M-700 Marine Transceiver Despite that the literature says, no lock-out is employed. For ham frequencies on 40, 80 or 160 meters, set the mode switch to the hard left position of "A3," to enable the lower sideband filter (all marine HF uses upper sideband). IC-28A, IC28H, TH-215A MODS: ED THOMAS, N2IHN KENWOOD TH-215A handheld transceiver out-of-band modification: 1. Remove two screws from belt clip 2. Remove 4 screws from back of radio 3. Slide front assembly off 4. Locate set of 4 jumpers: (top front inside) +--------------------------------------+ | | | | | +--------+ | | | | | | | | | | +--------+ | | | | +--------+ | | | | | J4: intact | J4 o---o | | | J3: cut | J3 o) (o +--------+ | J2: cut | J2 o) (o | J1: cut | J1 o) (o | | | | | | | | SPKR | | | | | | mic | | | +--------------------------------------+ 5. Reassemble radio. 6. Reset microprocessor: Turn radio on while simultaneously pressing both _F_ key and _ENTER_ key. -- DISCLAIMER: I do not own a TH-215A and have not verified the above information. Hopefully, the modified frequency range includes 162 MHz weather-broadcast freqs. ICOM IC-28A AND IC-28H To make the IC-28 transmit 138-174 MHz, cut D21 (no retuning required). D21 is a tiny glass diode standing on-end near the center of the upper circuit board, accessible by removing the top cover. The IC-28 is the only convertible ham rig I know that covers the 170-MHz federal government (including national park) frequencies. FT-411 OF YAESU, I have this Hand held, and by playing with it, I discovered a nice trick to increase it frequency coverage It is so simple that you don't even have to open your hand held. All you have to do is: 1. Make sure that the power switch is off. 2. press the UP arrow and DOWN arrow together, at the same time (those keys are also called A, and B and they placed at the upper right side of the keyped) 3. Keep pressing both buttons and turn the power on. That's all. Now you can receive 130-174Mhz, and transmit 140-150Mhz CAUTON: When you do this modification the memories can be erased. Ayhow I think it is not the end, and there are some more options. If you do have some more information about this Hand held, Please leave me a msg with it. FT 411 mods Here is some new interesting info about the FT-411: FT 411 OUT OF BAND MODIFICATIONS. --------------------------------- 1) Open the front cover 2) Locate the C.P.U. unit (it is located on the front cover ). 3) Locate Jumpers 1,2,3 and 4 , These are the band setting Jumpers 4) Jumpers No 1,2 and 4 should be disconnected ,and Jumper No 3 should be connected. 5) Close the radio . 6) Apply power to the radio and turn it on. The display will initialize with memory No 1 flashing and the frequency display will show 1.000 7) Now, adjust the display to the desired lowest receive frequency When done, press VFO. The memory CH will now show 2 flashing. 8) Adjust the display to the desired highest receive frequency When done press VFO . The memory CH will now show 3 flashing . 9) Adjust the display to the desired lowest transmit frequency When done ,press VFO. The memory CH will now show 4 flashing 10) Now, adjust the display to the desired highest transmit frequency When done, press VFO. The rig is now set for your programed band on transmit and receive. COMMENTS ------- 1) After the rig was programmed to the band and you want to change it to other ranges you will have to open the rig again and disconnect Jumper No 3 then to apply power to the radio ,turn it on again open it again ,connect Jumper No 3 back and repeat from steps 5 . TH-25AT TH-45AT Ok I've promised it for a long time and now it's time to live up to my promises. Here are some mods for the TH-25AT and the TH-45AT. Please note that I do not encourage transmitting on a frequency for which you do not have a license nor do I encourage transmitting on a non-amateur frequency without FCC type accepted equipment (in the United States). Lament: when are the Japanese going to produce a 440 FM HT for the US market that has receive coverage outside the US amateur band? Lord knows that there's a market for it - there's MONEY to be made. First let me recommend that you buy the service manuals for these radios. The service manual is not expensive (abt $15 I think) and it will greatly help you in performing these modifications. Look at the schematic for your radio. In the lower left hand corner is an IC labled IC2. This is an ASIC microprocessor. At the lower right hand corner of this uP are several diodes and pull-up/pull-down resistors. They are D4, D3, R19, R18, R28, R20, R21, R22, R25, R26 and a couple of resistors that are not even on the schematic that attach to B2 (pin 51 on IC2) and B3 (pin 50 on IC2). The TH-45AT schematic shows R23 on the ASIC uP pin B2. The schematic for the TH-25AT shows: R18-R21 R25 R26,27 R28 R36 TH-25A M,M2 -12 O X X X X TH-25A M3,M4,X -23 O X X O X TH-25AT K -11 O O X X X TH-25AT M,M2 -12 O X X X X TH-25E T -52 X X O O O TH-25E W -62 X O O O O And the schematic for the TH-45AT shows: R19-R21 R22 R23 R25 R26,27 R28 R36 TH-45A M1,M2,X -21 O O O X X O X TH-45A M3,M4 -22 O X O X X X X TH-45AT K -10 O X O X X O X TH-45AT M1,M2 -21 O O O X X O X TH-45AT M3,M4 -22 O X O X X X X TH-45E T -51 X O X X O X O TH-45E W -61 X O X O O O O where O means USED, and X means NOT USED. Some of the above codes are: K USA T England X Australia M Other Areas These components are found on the flexible circuit board under the display. To get to them, take the radio apart. Some unsoldering of obvious grounding wires may be necessary. You will see where the flexible circuit board plugs into a socket on the main circuit board. Before unplugging it, make sure you know what's in the memories, because they will be lost. Unplug the flexible circuit board and unfold it so that the components are accesable. One of the fold-out parts of the flexible board will look something like this: +----------------+ | R R R D3 R R | | 2 2 2 7 2 | | 5 3 2 1 | | | | R O O R20| The O's are solder pads. | 2 O O R19| | 6 O O R18| | O O R28| | | | R | | D4 6 | | +-------+ | | | | The fold out board is actually square, but with only characters for graphics, I couldn't draw it that way. On both radios, R36 is for the European tone burst to "whistle up" repeaters. On both radios, D4 is for selecting the type of display. With D4 in, the display is normal. With D4 removed, the display is a channel display. D3 is for selecting VHF or UHF. With D4 in, the radio thinks its a VHF radio. With D4 removed, the radio thinks its a UHF radio. Don't change this on your radio. On the TH-25AT: (All frequencies given in MHz.) R22 in R28 out This is how the radio is delivered in the USA. TX 144-148, RX 141-163 (I think). R22 out R28 in The radio tunes from 142-151. This may be the modification given to US MARS members. I don't remember where the unit will transmit. It may or may not transmit outside the range from 144-148. R22 in R28 in The radio tunes only from 144-148. R22 out R28 out Frequencies may be selected from 100-200 MHz (on the display only your PLL will not lock up in this entire range). In addition, TX is possible where your PLL locks up. R25 out Removing R25 disables automatic offset selection. R23 and R24 are used for selecting the step size for tuning. I can't remember which positions are for which step sizes, and alas I didn't write down what I found. If you want to play with this, go ahead. On the TH-45AT: (All frequencies are given in MHz.) R18 in R28 in This is how the radio is delivered in the USA. The radio covers 438-450 MHz. R18 in R20 out The radio is prohibited from tuning outside 440-450 MHz. R18 out R28 in The radio will only tune from 215-230 MHz. Note that the PLL would not lock up! (What did you expect?) Could it be possible that Kenwood originally planned a 220 version of this radio, but then scrapped their plans? R18 out R28 out The radio will tune from 200-500 MHz (on the display only - your PLL will not lock up over this entire range). Transmitting is possible anywhere your PLL will lock up. I have found a quick and easy way to retune your PLL (in the TH45-AT) with a minimum of test equipment. All you need is a scope and a small tuning tool. First, take off the battery pack holder plate. Then, remove the silvery sticker covering the tuning pot access holes. If the radio is positioned on its back, with the top folded over so that the touch tone pad is also facing down, the test point you want (TP1) is on the bottom half of the radio, near the center (left to right), and close to the battery; the tuning pot you want (TC1) is on the bottom, and closest to the PTT switch. Under no circumstances change the tuning of TC51. This is used to calibrate the output of the radio with the display the radio is giving; you don't want to mess with it. Once again, the Service Manual makes it very clear where these points are, if you are having trouble with my descriptions. On with retuning the PLL. With the radio on, and receiving, monitor the voltage and the waveform on test point TC1. Tune the radio DOWNWARDS in frequency until the PLL unlocks. Note that the radio will beep when this happens, and the waveform on TP1 will change. Tune the radio about 1 MHz higher so that the PLL locks up again, and note the voltage on the testpoint, TP1. Now, tune the radio to the LOWEST frequency that you want to be able to receive. Adjust TC1 until the voltage on the test point TP1 is the same as what was noted earlier. Button the radio back up, and you're done. You will not be able to tune the PLL to any range you want. There are limits. On my radio, I have been able to retune the radio so that I can recieve from 439.2-468.6 MHz with a set of batteries fresh out of the charger. The tuning range will probably diminish as the battery voltage decreases. I have not retuned the PLL on my 2m HT, but I'd imagine the same technique will prove fruitful. I may have some more information on these radios someplace. If I can find it, I will add to this posting, and post it again with the updated information. Enjoy. IC 32A MOD 1. Remove battery and antenna. 2. Loosen two screws on top of unit as much as possible without removing them. 3. Loosen 4 flat head screws on bottom of unit 1 turn. 4. Loosen 2 screws near PTT switch 1 turn. 5. Remove 4 black screws on back of unit. 6. Lift bottom of front cover .25 inch, slide it down .25 inch, then lift front cover up 1 inch. 7. Disconnect plug on 4 wires coming from the speaker. 8. Lay front panel on table up-side down being careful of the flex circuit. 9. All mods are done to the back of the front panel. Notice places for 5 axial diodes, which I will call 1 through 5, 1 being nearest the display. Add/remove diodes so there are diodes in positions 3 and 5. This will open up receive coverage for VHF & UHF and enable keyboard entry of the 10 MHz digit. 10. Notice 4 surface mount resistors slightly left of center directly above the speaker, lined up in a row. Solder the anode (the side without the bar) of two diodes to the right side of the lower of the four caps. Now find the CPU. It's the PGA under the shield near the top of the board. Find the row of pins on the CPU nearest the speaker. Notice the the 8th pin from the right has a thicker trace coming from it. Now notice that there are small solder pads about .25 inch toward the speaker on both the fat trace and the two traces to the right of it. Solder one each of the cathodes of the 2 diodes to the solder pads on the two smaller traces. This will open up the transmit for VHF & UHF. 11. Put unit back together in reverse order. This procedure worked for my unit (and many others), but I can't guarantee it will work for yours. Bill Pherigo WR0Y PORTED AND REALIGNED FROM PC TO AMIGA FORMAT BY BOB G0LBQ - N6XDI.