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Forum: Radio Mods
 Topic: Kenwood Mic to Icom Radio Conversion
Kenwood Mic to Icom Radio Conversion [message #162] Sun, 03 February 2008 13:14
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Kenwood Mic to Icom Radio Conversion


To those who may desire to use a microphone with a different transceiver (other than the original microphone brand) For a Kenwood Mic to work with an Icom Radio wire the mic plug as discribed below:

Pin #1 stays on Pin #1
#2 move to Pin #5
#3 stays on Pin #3
#4 stays on Pin #4
#5 move to Pin #2
#6 move to Pin #8
#7 stays on Pin #7
#8 move to Pin #6

For Icom Mic to Kenwood Radio you must preform a special Mod on the mic

Note: ALWAYS READ THE SERVICE MANUAL ON BOTH RADIOS BEFORE TRYING THIS MODIFICATION

[Updated on: Sun, 03 February 2008 13:21]

 Topic: Uniden BD996 Discriminator tap
Uniden BD996 Discriminator tap [message #161] Sun, 03 February 2008 13:03
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Uniden BD996 Discriminator tap


OK, I dug around a little and it appears our friends at Uniden made it real easy!

Take off the outer case shell, and then the top inner case. Just about dead center on the board look for the solder pad labeled "DISC". Run a single insulated wire to this point to a jack of your choice (I prefer RCA jacks) mounted on the rear of the radio. I also like to use a tantalum capacitor in line with the jack as well.

If you take the bottom inner cover off the radio you will see the best place to install the jack appears to be the area of the bar code/serial number label. This is kind of thick double walled metal so be careful drilling. You could also just run an audio cable into the radio through the threaded rear hole or even one of the holes on either side of the radio's rear.

Ray Colvill

[Updated on: Sun, 03 February 2008 13:05]

 Topic: Expand Frequency Coverage on TX/RX for the Icom IC-W32A/E
Expand Frequency Coverage on TX/RX for the Icom IC-W32A/E [message #158] Sun, 20 January 2008 14:24
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Icom IC-W32A Mod



Expand Frequency Coverage on TX/RX for the Icom IC-W32A/E

NOTICE: We can not guarantee specifications beyond the amateur bands. Not responsible for any damages incurred in attempting this procedure. This modification may void all warranties.

1. Remove the battery.

2. Remove the 4 screws holding the rear cover and the 2 lower screws holding the shield in place in the battery compartment. 3. Carefully lift the rear cover with the battery comparment shield away from the front cover.

4. The front and rear sections are connected together with a flex strip connector. Carefully lay the rear section aside by lifting upward, turning and laying the rear section over away from the front cover leaving the flex strip connected.

5. With the front cover section in front of you, antenna connector to your left, locate the notch at the right side of the exposed PC board. Next locate the three, 3 terminal diodes near the lower corner of the notch. Two are in line from left to right, with the third below the diode to the right. This last diode (the one below the right one) is diode D523. Very carefully remove D523.

6. Reassemble the radio in reverse order.

7. Perform a system reset by holding down the Squelch button (on the side) and the Band button while turning the radio on. Note that all memories will be erased, so write down anything you want to save and reprogram.

VHF coverage will be from 140 to 170 (plus or minus a bit) on Tx/RX
UHF coverage will be from 430 to 470 (plus or minus a bit) on TX/RX
 Topic: Ham 900 Band Filters on ebay
Ham 900 Band Filters on ebay [message #154] Mon, 31 December 2007 10:31
DBMdbm
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Registered: December 2007
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FYI Maxtrac 900 ham band filters for sale on ebay Item number: 180201771850
 Topic: TM-941A Mod - Open Transmit Mod
TM-941A Mod - Open Transmit Mod [message #150] Sun, 02 December 2007 14:00
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TM-941A Open Transmit Mod

The following mod will allow the TM-941A to transmit from 142.000 to 151.995 mhz, 420 to 450 mhz and 1100 to 1400 mhz.

1. Disconnect power supply and antenna

2. Remove the detachable front panel assembly

3. Locate a green jumper wire on the control board, in the body of the transceiver. The wire is located towards the left edge of the board

4. Cut the green wire loop in half and insulate

5. Install front panel assembly, and connect power and antenna

This mod works, but is done at your own risk

Author: ZS5

J
 Topic: Preamp mod for Yaesu FT-890AT
Preamp mod for Yaesu FT-890AT [message #149] Mon, 26 November 2007 21:57
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Try this Preamp mod for the Yaesu FT-890AT...

Yesterday we made a similar modification, as I mentioned with my FT-990.

My friend (HA5AUC) have an FT-890. We changed the parallel-connected gg 2SK125's in the preamplifier stage to J310's. (Q2008 and Q2006) (Be care with the different pin-out!).

Results: bit less noises, bit more gain.

HA5BWW
 Topic: BC95XLT BC-92XLT BC-72XLT Pro-83 Pro-84 Frequency Counter
BC95XLT BC-92XLT BC-72XLT Pro-83 Pro-84 Frequency Counter [message #146] Sat, 17 November 2007 13:47
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The Uniden BC-95XLT Can Be Used As A Frequency Counter. To enter this mode Press "HOLD,3 and 0" while turning the Power On. You then can change the group of frequencies you wish to check. To do this use the Up and Down Arrow Keys. The Scanner will display the strongest frequency transmitted. Example: To check a Citizens Band Radio frequency, select The Lo group. If you Transmit on Channel 20 the scanner will display 27.205 MHz. You can check with a Ham Radio, Marine, GMRS, etc. It will display the frequency used. This Will also work on Uniden BC-92XLT & BC-72XLT. Should work with Radio Shack PRO-83 & PRO-84.
 Topic: Alternate fan mod for IC-7000
Alternate fan mod for IC-7000 [message #141] Tue, 28 August 2007 02:09
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!! IF YOU ARE UNSURE ABOUT PERFORMING THIS MOD DON'T!!

!!IF YOU DAMAGE YOUR RADIO YOU ONLY HAVE YOURSELF TO BLAME!!

I have performed this mod on MY OWN radio without any adverse affects and my LDG AT-7000 atu still works as it should.

Before this mod after been turned on for an hour or so the temp meter on the radio would show around 50% on the scale (7 or 8 bars), after the mod the temp meter shows around 25% on the scale (4 bars).

First remove the top cover and remove the fan from the radio,

take a 100ohm resistor and solder a length of wire to each end and cover with heat shrink tubing. Cut the red wire to the fan and attach one of the resistor wires between the two halves and cover with heat shrink tubing.

Next follow the ORANGE wire from the ATU molex socket on the back of the radio to where it is soldered on to the DDS unit (top right hand corner at the back of the radio) and attach the remaining resistor wire to this point, position the resistor and wires so that they look neat and tidy and then refit the fan and the top cover, mod is now complete.

M3SVO
 Topic: Monitor AM on the Yaesu FT-8800
Monitor AM on the Yaesu FT-8800 [message #140] Sat, 18 August 2007 23:45
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Monitor AM on the Yaesu FT-8800

How to monitor AM outside the default Aircraft band:

Depress the set button once and rotate the left selector knob to menu item 46, it will say AM.

Select the frequency you wish to operate by VFO. You are now on AM. If you turn VFO one click to left or right, radio will revert back to FM.

You can program this into a memory channel and it will stay in the AM mode.

Author: KC9BZX
 Topic: Yaesu FT7200 Mod - Call Tone 1750 Hz volume increase
Yaesu FT7200 Mod - Call Tone 1750 Hz volume increase [message #139] Sun, 05 August 2007 00:14
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I'm a long time user of the Yaesu FT-7200. This transceiver came with a very low level 1750 Hz repeater tone.
Nearly no repeater could be opened easily, at least you hda to press the call button a very long time.

If you compare the volume/deviation of different transceivers you will 'hear' what I'm talking about.

I know that nowadays the repeaters should use a lower deviation, but this can be adjusted with a summing resistor R1058 on the main unit. See the picture attached.

Please be aware that this modifihoneyion also influences the level of the CTCSS sub-tones.Check the circuit diagram for details.

The recommendation to REPLACE R1058 I did not like, It might damage the PCB as the components are glued to the board. It's much easier to switch 68 kOhms in parallel, changing the value allows an adjustment of the deviation. (68k//68k=34k) Comparing the volume (and spectrum on a spectrum analyzer) I found out that 68 kOhms work fine.
Use a very small wired resistor or a SMD version and be sure that not short circuit occur.

Please proceed at your own risk.

Good luck! Wolfgang DH3WO

[Updated on: Sun, 05 August 2007 00:15]

 Topic: Add 30-meter Transmit to Kenwood TS-180S Transceiver Mod
Add 30-meter Transmit to Kenwood TS-180S Transceiver Mod [message #138] Sat, 21 July 2007 00:40
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The WARC band kit for the TS-180S is a pretty rare item these days, but I figured it should be easy to add 30m CW transmit capability to the non-WARC stock rig, as it already receives the 10 MHz band using the normal receiver stages.

The 10 MHz band is marked JJY/WWV on the band switch. The schematics revealed that the 30-meter part of the WARC band option adds an additional low-pass filter to the LPF board, and a band pass "AUX 3" filter to the Coilpack board.

I found you could substitute a 10.7 MHz FM transistor radio IF transformer (I used a Mouser 42IF122 for the bandpass filter. For the low-pass filter I added two wire jumpers on the two rear-most sections of the bandswitch (at the LPF board) so that the 7 MHz and 10 MHz lugs were connected together. This puts the 7 MHz low-pass filter section is also in-line for the 10 MHz band.

The only tune-up necessary was to set the rig to 10.120 MHz or so and peak the new IF transformer.

I achieved about 60 watts output and confirmed the signal was clean by feeding a sample of the output into my spectrum analyzer. The spurious outputs were down below the original specs of the rig, so I called it "good" and made some contacts on 30-meter CW.

Steve Johnston WD8DAS
July 2007
 Topic: Programming Cable for Icom IC-F12
Programming Cable for Icom IC-F12 [message #136] Sat, 02 June 2007 01:36
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Programming Cable for Icom IC-F12

Simple handle programmer for radio transceiver ICOM ICF12, mounted with one plug P2 stereo and a female connector DB25 where bolt 15 of the female DB25 will be for data, bolt 1 land. It will have to be made to jumper between bolts 4 and 11 of the female DB25, this female connector DB25 will go on in any interface on type RIB to a PC. Detail of plug P2 stereo that will go to the radio:

bolt 1 nc
bolt 2 data from bolt 15 female DB25
bolt 3 gnd from bolt 1 female DB25

[Updated on: Sat, 02 June 2007 01:38]

 Topic: IC-P7A MARS Mods
IC-P7A MARS Mods [message #135] Wed, 30 May 2007 21:16
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IC-P7A MARS Mods

The following mod works exactly as described for the Icom IC-P7A (see mod for the IC-E7)

NOTE: The sticker is a very small (1cm) one and in the P7 the pads are shorted with a SMT diode. With a steady hand, a jewlers loupe, and some really small tweezers, you can pluck the diodes off lohoneyions 3 and 4 (as noted below.) As per EB4EQA:

TX bands configuration via 4 solder pads in the PCB, behind a square sticker lohoneyed under the battery, on the top-left corner.

I've number the pads as seen while looking to the back of the transceiver, with no battery and the PTT looking to your right.

  1234    VHF_TX     UHF_TX
OOOO 136-174 400-479
OOOS 136-174 430-440
OOSS 144-146 430-440 (factory)

O = Open
S = Short

Procceed at your own risk.

[Updated on: Wed, 30 May 2007 21:17]

 Topic: Open Icom IC-M800 or IC-M810 to ham Frequency
Open Icom IC-M800 or IC-M810 to ham Frequency [message #129] Mon, 07 May 2007 20:01
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Open Icom IC-M800 or IC-M810 to ham Frequency

This modification allow the IC-M800 or IC-M810 marine band transceiver to be used in ham bands.

To make this mod you must remove power, disconnect the antenna and remove protective top and bottom cover to gain access to the RF UNIT which is on the lift side of the radio.

This mod require your cut D25 and D26 on this board. Also you must cut wire W1 on the logic unit board.

 Topic: Icom 02AT Frequency Modification
Icom 02AT Frequency Modification [message #64] Sun, 25 June 2006 16:41
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icom 02at mod 140-163 mhz

a. locate a copy of the june 1986 issue of 73 mag.

b. the article on pg. 60 is for models with id numbers lower than 35,000. if yours is one of the newer models like mine..... then follow these changes:

1. read the entire article b-4 doing anything!!!

2. follow steps 1 to 3 on pg. 61 "modify ur 02at" then s t o p ! refer to fig.2 on pg. 60 and remember the diodes on urs are in different locations than in the pix.

3. using a very small flat blade iron and some solder wick remove the the three leg diode d2 notice that the numbering for d1,d2,d3,d4 are off to the left of the actual location of the diodes on the board.

4. resolder d2 down in position d5 try to use the solder on the pads.. only add solder to the pads if absolutely necessary, b-4 you put the diode in place to avoid bridging.

5. solder a store bought 1n914 or 1n4148 diode from the top pad to the bottom left pad of d4. you will need to bend and cut the leads of the diode and pre-tin with solder. bend the leads of the diode so that the body of the diode across the bottom right pad covering it up. the banded end ohe the diode should be facing down towards mhe bottom right pad.

now you are ready to follow steps 7 to 13 and the rest of the instructions in the article. the only difference you will find is that a letter "u" will flash to indicate unlocked instead of the entire display flashing.
 Topic: Audio Modification for Icom IC02 and IC04 Radios
Audio Modification for Icom IC02 and IC04 Radios [message #63] Sun, 25 June 2006 16:38
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This audio mod works on the 02 and 04AT. It increases the level of audio, as well as rolling off some of the lows. Sounds real nice. It involves the circuit around Q105.

1. Replace C119 with a .01 uF cap (disc ceramic is fine).

2. Parallel R131 with a 1 uF cap (use a tantalum cap).

3. Parallel R132 with a .01 uF cap (disc ceramic is fine).

This is not the same mod as the one International Radio is advertising, which involves changing C117.

I tried an AB-1 Audiolaster from Engineering Consulting, and was very unhappy with the results. I am very pleased with the audio given by this mod (much cheaper too!).
----------------------------------
 Topic: Icom IC02 PL Out of Band Modification
Icom IC02 PL Out of Band Modification [message #62] Sun, 25 June 2006 16:36
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The following method of modifying the Icom IC02. This one should give you PL out of band without jumpering 5 VDC to the tone chip. Use 1N914 or equivelent when adding diodes.

1. On the logic matrix, remove D402 and D403.

2. Add D402, D403 and D404 with the cathode at 4 o'clock and the anode at 12 o'clock.

3. Retune the VCO to cover your desired frequency spread. My 02AT did not want to go beyond 163 MHz. I have a friend whowas able to get his to the low 170s.

4. To jump from 140 to 150 or from 150 to 160 (or vice versa) you must "tune across" the boundry, in the same way that you do for an unmodified 02AT. For example, key in 149.995 and then move up until you are in the 150s. You can then enter any 150 MHz frequency (starting with the MHz).

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


***->Be careful not to transmit out-of-band, or accidentally operate on any non-amateur, unless you are authorized to do so.

DO NOT JEOPARDIZE YOUR LICENSE!
 Topic: Expanding Functions for the IC-V8000
Expanding Functions for the IC-V8000 [message #58] Mon, 08 May 2006 23:54
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This PDF contains content on the ICOM V-8000:

1. RX Frequency Expansion
2. TX Frequency Expansion
3. ANI Function
4. Voice Scrambler Function
5. MIC Gain Level
6. Wide and Narrow Function

Click here for the PDF document for these function mods

[Updated on: Mon, 08 May 2006 23:55]

 Topic: Icom IC-2720H Out of Band Mod
Icom IC-2720H Out of Band Mod [message #57] Fri, 28 April 2006 23:23
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 Topic: Alinco DR-600 Mod Extend TX/RX
Alinco DR-600 Mod Extend TX/RX [message #54] Fri, 28 April 2006 23:05
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Hi, I just got the info on how to modify the Alinco DR-600. I have activated these mods and they seem to work fine. Here they are:

Mod 1 - Activate 108 - 142 MHz and 810 - 998 MHz Receive
--------------------------------------------------------

Remove head unit from radio and open it up.

Inside you will see a red and blue wire.

Cut the red wire.

Open the main unit and attach a wire to CN-205. This will be your antenna for 810-998 MHz.

Close everything up.

Reset the CPU by holding down the FUNC key while you turn the radio on.

To use: The VHF key toggles between 108-142 and 2m. This toggle only works in VFO mode.

The UHF key toggles between 810-998 and 70cm. This toggle only works in VFO mode.



Mod 2 - Extened tx/rx on 2m and 70cm
------------------------------------

Remove head unit from radio and open it. (2 screws on back)

Inside you will see a red and a blue wire.

Cut the blue wire.

Put everything back together.

Reset the CPU by holding down the FUNC key while you turn the radio on.

You can now transmit and receive on the following freqs: 130-174MHz and 400-517MHz

Be carefull!!!!! You can now transmit outside of the HAM bands. Don't do this! If you do you WILL get caught and the FCC loves those $10,000 fines.



NOTE: I take no responsibility for these modifications. If you blow up your radio it is not my fault. If you have any questions about these mods call Alinco.



Chris Levin levin@cosmic.physics.utah.edu
 Topic: BC2500XLT Cellular Mod
BC2500XLT Cellular Mod [message #53] Fri, 28 April 2006 23:02
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I have never tried this mod. I have one page which I received from Grove about this modification for cellular restoration.

The page notes that the modification may not be really necessary, because you can still hear the cellular communications in the image frequencies 21.6 MHz higher that the true cellular ranges. Thus, you will hear cellular calls in the 894.01 to 915.60 MHz range on your BC2500XLT without modification.

If you really want to do the modification, here are the step-by-step directions. Most of what follows is copied verbatim from the Grove sheet, which does not have a copyright notice on it. Therefore, I'm bassuming it's OK.

1. Remove the antenna and battery pack from the BC2500XLT. Lay it on its face on a soft cloth or towel, bottom of the radio facing you. Remove the two upper (black) and two lower (chrome) screws.

2. Carefully pry the back loose from the radio and lift it off. Similarly, grasp the visible circuit board by the edges and carefully pull it away from the radio just far enough to separate it from the white (11 pin) Molex connector. Do not stretch the remaining ribbon connector. Lay the board alongside the radio.

3. Locate microprocessor chip "UNIDEN UC-1513A", the speaker, and the battery terminals. Below the microprocessor and above the speaker and battery terminals, locate the cluster of chip resistors marked "104". Using a magnifier and fine-point soldering iron, unsolder the lower-left-most chip resistor and move it one place to the left, soldering it in place.

Cellular restoration is now complete. Rebassemble the radio by reversing steps 1 and 2, and test it by entering 879.990 MHz. Search steps in this range will be the correct 30 kHz.

As I said, I have not tried this modification, so I can't testify to whether it really works. Grove states that Grove Enterprises bassumes no responsibility for damages or other liability resulting from attempting to duplicate this procedure. It is possible (probable?) that this modification may void your warranty.

Also keep in mind that there are at least two versions of the BC2500XLT. I don't know whether these modification applies to all versions.

Finally, the obligatory note to remind you that monitoring mobile telephone conversations, including cellular, is against federal law.
 Topic: Cherokee AH-50 HT Mods
Cherokee AH-50 HT Mods [message #52] Fri, 28 April 2006 22:58
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Hello,
Here is an output power mod for the popular Cherokee AH-50 6 meter handie talkie. It is the first mod I've ever seen for this radio. Regular high output is just under 5 watts. After this mod you can get about 6-7 watts output while using an external 12 volt dc input and on low power about 3 watts is typical.

1.Remove all external screws and carefully pull apart the unit. Be careful not to lose the rubber PTT and feature button pads that will become lose while doing this as well as the plastic slider that locks the battery pack and power cord in place.

2.You will notice there are two separate,sandwiched circuit boards that make up the unit, one is the CPU and LCD display, the other is the RF component section. Gently pull the display board free of the RF section. They are joined together by a multi-pin terminal.

3. With the RF section fully exposed you should see a metal grounding pad that covers the underside of the RF section as well as the rf output coaxial wire. Desolder the legs of the grounding pad, as well as the lead of the coaxial wire closest to the BNC and move the grounding pad to the side, exposing the underside of the board. Use extreme caution as there are multiple surface mount components very close to these points.

4.Find the main output transistor-2SC2078 marked "C2078". It very easy to spot. It is screwed onto the radio's heatsink. With the grounding pad moved, you can now desolder the three pins on this transistor and remove. Replace with a 2SC2166. Be sure to use heatsink compound on the back of the new transistor and the heatsink during replacement. Locate an inductor with a core behind and to the left of the output transistor. There is a small hole in the heatsink above it for tuning. Tune this and all the other spring-like coils around the output final for maximum output at 53 MHZ. Make sure the radio is set on high power for this! You should see close to 6-7 watts output now, instead of the stock 4.8 watts. Rebassemble radio in reverse order and enjoy. Don't forget the radio will put a big strain on your battery pack on high power with the higher output. It is advisable to use low power setting with battery use and high only when an external 12v source is applied.

'73 KB3HAZ
 Topic: Alinco DJ-160 Mods
Alinco DJ-160 Mods [message #51] Fri, 28 April 2006 22:55
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The new Alinco DJ-160 Radio will receive between 137-174 Mhz, and transmit in the 2Meter band only (144-148Mhz). A simple modification to the radio will enable it to transmit in the full range it receives currently. I have not tested the output power on other frequencies (Due to my one and only watt meter getting fried)however I have tried setting a weather receiver a small distance away, and I did hear the radio in the receiver. To make the mod, the following must be done: (I bassume that you have some experience with electronics and that you can tell a wire from a resistor, from a transistor)

1) Take the battery of the radio by lifting the battery release button. If you look at the bottom of the radio, there will be a metal plate that is held on with 4 small screws. Take this plate off, noting exactly how the clip was held on (like the slot for the battery release clip)

2) On the back of the radio there are two screws that hold the back of the radio on, take these screws out.

3) Now you should be able to lift the bottom part of the radio by the battery release button slightly apart. I was told that you should take the top knobs off, but I found that I didn't have to.

4) If you take the Battery Release Button and turn it about 90 degress, the button should come out easily. After you get the small piece of plastic that is the button, you should see a yellow wire behind where the clip was.

5) Take a small wire cutter and CUT this YELLOW wire. You should probably make sure that the wire doesn't have bare metal showing from a lousy cutter, because I don't think that grounding this wire to the case would be HEALTHY for your radio. Smile

6) After You cut this wire. bassemble the radio, and just before you turn on the radio, do a power reset by holding the FUNC button while turning on the radio. This will reset the radio to ALL of the factory set parameters. YOU WILL LOOSE PROGRAMMED FREQUENCIES that were programmed into the memory mode of the radio, so just write the frequencies down before proceding with the above instructions.

7) The radio should be just like new, except that the transmit will be enabled for ALL frequencies! GOOD Luck!
 Topic: Kenwood TM-2550 Mars/Cap
Kenwood TM-2550 Mars/Cap [message #46] Fri, 31 March 2006 23:49
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The TM-2500 series radios may be easily modified for use on MARS/CAP frequencies from 141-150.995mhz. Locate the control unit (X54-1860-XX) on the bottom of the radio. This is the same board that the TU-7, and or MU-1 are mounted on. Just to the left of IC3 you will find a row of diodes. Cut diodes D8, and D11. After the diodes have been cut you will have to "reset" the microprocessor. Microprocessor Reset. 1. Press and hold the [PS] key. 2. Turn ON the power switch. 3. Release the [PS] key. All of your programmed data such as memory channel data, DCL data, and Phone number data will be erased and you will have to reprogram them. If the radio is not reset, it will not recognize that you have cut the two diodes.
 Topic: Kenwood TS-940s IF-10C Serial Interface
Kenwood TS-940s IF-10C Serial Interface [message #43] Sun, 19 March 2006 23:36
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The TS-940s inside serial interface is not available now so here is a solution.

Kenwood TS-940s Serial Interface

Kenwood TS-940s Serial Interface

Kenwood TS-940s Serial Interface

Kenwood TS-940s Serial Interface

Kenwood TS-940s Serial Interface

Kenwood TS-940s Serial Interface

Kenwood TS-940s Serial Interface

Kenwood TS-940s Serial Interface

Kenwood TS-940s Serial Interface
 Topic: IC-208H Extended RX-TX mod
IC-208H Extended RX-TX mod [message #42] Sun, 12 March 2006 17:33
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  • Place the radio with the front panel toward you and bottom side / speaker side UP.

  • Remove the (4) screws located in each corner.

  • CAREFUL! Go slow, you will need to disconnect the speaker cable while removing the cover.

    Look at the lower right hand corner of the main printed circuit board.

  • You should see a silver crystal with the number "D196D3C" printed on it.

  • Just above the crystal, you should see an (8x8) matrix pad (see below diagram).
    o o   o o   o o   o o
    o o   o o   o o   o o
    o o   o o   o o   o-o   <-- Remove
    o o   o o   o o   o-o   <-- Remove
    

    Note: there are ONLY (2) resistors in place. (Bottom right and the one directly above it).

  • REMOVE BOTH RESISTORS [Do NOT attempt this unless you know how to use a low wattage soldering iron]



  • RESET THE RADIO, hold the [SET LOCK] and [S.MW-MW] buttonsdown during power-up.

    DONE! New RX/TX Ranges

    118.0000  -  135.9875    RX-AM only
    136.0000  -  173.9875    RX & TX (15% RF power fall-off at lower freq, Full 
                             power at high freq)
    230.0000  -  399.9875    RX only
    400.0000  -  478.9875    RX & TX (Do NOT transmit below 410MHz on HI-PWR, 
                             VSWR fold-back)
    479.0000  -  549.9875    RX only
    810.0000  -  849.0000    RX only
    849.0000  -  869.0000    RX only
    894.0000  -  999.9875    RX only
    

    Author: KD4CWB
  •  Topic: IC-7000 Fan Mod - Cool as ice
    IC-7000 Fan Mod - Cool as ice [message #40] Tue, 07 March 2006 01:09
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member

    READ ALL OF IT BEFORE PREFORMING THE MOD!

    Use a baby thermometor ( the electric kind w/ the digitial readout ) and see just how hot your rig is running before preforming the mod, I know most all of my readings were over 106F then the thermometer errored out as the temp was too high.

    Tempurature Measurements were made with a baby-tempurature thermometor ( sorry its all I had at the time ).

    Heres the Proof!

    ----------------
    top - left front 94.6F
    top - left rear 103.8F
    top - right front N/A (below 85.5F unable to get reading)
    top - right rear 92.7F
     
    Right side front 90.6F
    Right side rear 91.5F
     
    Left side Front 95.0F
    Left side Rear 98.1F
     

    After cw keying for aprox 5 min continous duty the heat generated by the IC-7000 did rise enough to enable to the temp control circuit. Heres the good news!

    Once the temp control circuit kicks in, the fan goes into high-rpm mode!!! Then returns to 'normal' operation with the 2W / 100ohm resistor voltage.

    So with this mod, you get a dual speed fan without any additional modifications!!

    Forgot to mention, when you goto solder the lead to the red wire of the fan, please place a rag or something undeneath the area you will be working in ( its pretty tight ) to prevent any unwanted solder dripping down onto the main board.

    When closing everything all up, there is a little pink sticky pad ontop of the cover unit to access the mars/cap and tvro mod. Place your wire so its right on top of the sticky pad. Seemed to be the best place for it at the time.

    Options, the Red wire from the fan connecter to the main board could be snipped between the connector and the solder joint to avoid any complications with the temp circuit enabling.

    Additionally, the back left of the rig, still feels warm to the touch but its more of a luke-warm, instead of what it was previously which was excessivly hot. The back right, front left and front right all feel cool to the touch.

    Im sure there are better ways of preforming this modification, although just stealing 0.14A from the 12v+ DC on the tuner port seemed to make the most sense, since an LDG Tuner only uses 300mA when in operation.

    Although I do not know how this will affect the autotuner as I do not have one, I am unable to test this modification with an autotuner, such as the LDG Z11 or Z100.

    Your Icom 7000 Running Hot? ... Heres the FAN mod!
    ( This has been untested with an inline tuner )

    1. Tuner Lead #3 is +12v DC, tap into Tuner Lead #3 with a wire ( theres enough room to simply slip a solid copper wire into the crimp for lead #3 )

    2. Add a 100ohm Resistor at the other end of the solid copper wire ( a 100ohm pot will work if you wish to be able to vary the speed of the fan )

    3. Strip the insulation of the red wire to the fan back just enough to make a solder connection to the 100ohm resistor / 100ohm pot. We used a lighter to burn away a bit of the insulation in the middle of the wire b/t where it connects to the board and where it connects to the fan itself.

    Wrap it all up with some electrical tape to prevent grounding. and Whala! Your Done!!

    Tuner Port on back of the IC-7000
    ^
    1
    2
    3 +12v DC -> wire -> 100ohm resistor -> fan red wire
    4
    -
    

    A 100ohm Pot could be used instead of a resistor, values below the 100ohms will increase fan speed.

    0 resistance - sounds like an airplane.

     Topic: Extended Frequency Enhancements for the Yaesu FT-23R(2M), FT-33R(220), and FT-73R(70cm)
    Extended Frequency Enhancements for the Yaesu FT-23R(2M), FT-33R(220), and FT-73R(70cm) [message #35] Wed, 14 December 2005 00:21
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    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:
    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 bassist.

    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. Dissbassemble 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.

    (**)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 , 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
    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 rebassemble radio.

     Topic: Modification FT-27 expanded frequency range
    Modification FT-27 expanded frequency range [message #34] Wed, 14 December 2005 00:19
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member

    Remove the screws holding battery track and rear cover.
    Locate the "CONTROL UNIT".
    Close jumpers 1, 3, 7, AND 8.
    Rebassemble the radio.
    Turn on the radio and program it as following:
    "1" 135.000 PRESS D/MR THIS IS LOWER RX LIMIT
    "2" 185.000 PRESS D/MR THIS IS UPPER RX LIMIT
    "3" 135.000 PRESS D/MR THIS IS LOWER TX LIMIT
    "4" 185.000 PRESS D/MR THIS IS UPPER TX LIMIT

    Press and hold D/MR, T and REV while TURNING ON if you need to reset or reprogram the radio.

    Notes:

    Jumper 5 is for 25 KHZ steps default value.
    Jumper 9 is for battery back-up.
    Jumper 10 is for 1750 HZ repeater tone access.


     Topic: Yaesu FT-26 Expanded Frequency
    Yaesu FT-26 Expanded Frequency [message #33] Wed, 14 December 2005 00:18
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    1. Remove the battery and antenna.

    2. Remove the four screws holding the back track.

    3. Remove the two screws in the back case.

    4. Carefully seperate the front cover.

    5. Locate and remove solder on jumper pad 10. (on the control board)

    6. Apply solder to jumper pads 1,3,7 and 8.

    7. Rebassemble the radio.

    8. Turn radio on and each channel indicater will blink.

    9. Enter the following frequencies. (use the [F] and up arrow keys)

    CH.1 135.000 Press [D/MR] Lower Rx limit
    CH.2 174.000 Press [D/MR] Upper Rx limit
    CH.3 135.000 Press [D/MR] Lower Tx limit
    CH.4 174.000 Press [D/MR] Upper Tx limit

    I accept no responsibility or liability for the results of any modification.
    Performing modifications and the use of modified radios may be a violation of laws.If you have any doubts do not perform any modifications.

     Topic: Yaesu FT-10 Extended Transmit Mod for 140-174MHz use
    Yaesu FT-10 Extended Transmit Mod for 140-174MHz use [message #32] Wed, 14 December 2005 00:06
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    1. Remove antenna and battery.

    2. Locate the Ni-Cd battery sticker on the back of the radio chbassis. Pry up the corner of the sticker and peel it off carefully.

    3. Remove the two screws located under the sticker. These retain the keypad.

    4. Slowly lift off the keypad. Use care not to dislodge the gasket.

    5. Locate and unsolder the 0 ohm chip resistor at location "M" (see diagram below).

    6. Re-install keypad with two screws. Be sure gasket is properly seated.

    7. Replace the Ni-Cd sticker if desired. Reattach battery and antenna.

    8. Press down and hold the Top-Notch and Lamp button while turning the radio on.
       | knob |
     +---------------------+
     |  +---------------+  |
     |  |  LCD Display  |  |
     |  |               |  |
     |  +---------------+  |
     |  -----------------  |
     |  -----------------  |
     |  -----------------  |
     | (on/off) ---------  |
     |                     |
     |  +---------------+  |
     |  |    Ribbon     |  |
     |  |    Cable      |  |
     |  |    ||||||     |  |
     |  |  o         o  |  |
     |  |         ::    |  |
     |  |           #:  |  |
     |  +---------------+  |
     +---------------------+
    
    # = Lohoneyion "M", chip resistor to remove
    The board may actually has an "M" near the correct resistor.

    [Updated on: Wed, 14 December 2005 00:12]

     Topic: Icom 32AT Open Transmit for VHF & UHF
    Icom 32AT Open Transmit for VHF & UHF [message #21] Sun, 03 July 2005 23:51
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    MODS FOR ICOM 32AT

    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
     Topic: Special Buttons on IC706mkII
    Special Buttons on IC706mkII [message #17] Sat, 26 February 2005 16:00
    kc2nda  is currently offline kc2nda
    Messages: 31
    Registered: December 2004
    Location: New Paltz
    Member
    I have tried some special buttons on IC706mkII:

    Push TS and DISPLAY while power up and you will see a strange power on check.

    Push P.AMP/ATT and RIT/SUB while power up and you will be able to see SHIFT-ADJ on your 706mkII. Dont know what this is for, recalibrating ?

    I think that these things even works on the older version of 706, dont know.

    73 - Dennis, SM6WXO @ SM6JZZ
     Topic: More talk power on SSB from your Icom 706Mk2/Mk2G and Alinco DX70TH
    More talk power on SSB from your Icom 706Mk2/Mk2G and Alinco DX70TH [message #16] Sat, 26 February 2005 15:58
    kc2nda  is currently offline kc2nda
    Messages: 31
    Registered: December 2004
    Location: New Paltz
    Member
    The following adjustments are to increase the average talk power on SSB for the above radios. If your radio is still under warranty, check with your supplier to ensure warranty will not be invalidated



    For both these adjustments you will need a very small cross-point screwdriver and a steady hand! Do not proceed if you are not confident!



    Alinco DX70TH: Turn up the microphone gain as detailed in the manual. This should be set to maximum. The adjustments described here is concerned with the ALC control. ALC action is indicated by the TX light which should glow brighter when speaking into the microphone.

    Remove the top cover and locate the high power/50w switch (this switch location is detailed in the manual, it is the only switch visible under the top cover). To the left of the switch there should be a small pot which is for the ALC. Just above the pot printed on the circuit board is 100w. Set the radio to 28Mhz and while speaking into the mike turn the pot counter clockwise until the TX light just fails to glow brighter. Back off slightly to restore the increase in brigthness of the TX light while speaking into the microphone. Replace the top cover.

    This adjustment increases talk power considerably and for local contacts on SSB the compressor should be switched off.

    Icom 706Mk2/Mk2G: The Icom 706 series are notorious for low talk power on SSB. A simple tweek of the ALC can solve the problem. This procedure was published in Radcom July 1999 but is updated here to include the IC706Mk2G. As far as I can ascertain, the later model 706MK2G seems not to suffer from the problem of low talk power and this mod may not be necessary. Remove the top cover. At the front edge of the main circuit board (to the left of the crystal filter slots, with the front of the radio facing you) should be a small pot. In the 706Mk2 this is R511 and in the 706Mk2G it is R579 (the number is not actually printed on the board!). The pot may be obscured by printed ribbon. This pot needs to be turned clockwise while speaking into the microphone, with power set to high and microphone gain at 6 (compressor should be switched off). Adjust for maximum talk power.

    The article in Radcom claims that this adjustment will bring the 706Mk2 up to 100w pep without the need for the compressor. For the 706MK2G (early models), adjusting R579 can give a dramatic increase in talk power although you will find that you will still need to have the microphone gain turned up to 10 and the compressor switched on. On my own set I have noticed that some bands give more talk power than others. On 160, 80 and 2 meters I get nearly full power by speaking into the mike (gain at max and compression on). However on other bands the increased talk power is not so dramatic particulalry on 10, 20 meters).

    Another way to boost the talk power on the 706 series is to use a preamplified microphone. If you do decide on a preamplified microphone reset R511/R579 back to it\\\'s original postion or distortion may result.

     Topic: Icom V8000 MARS Mod - STRAIT FROM ICOM
    Icom V8000 MARS Mod - STRAIT FROM ICOM [message #14] Wed, 29 December 2004 01:55
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    Here is the Icom MARS modification that I requested from the manufacturer and had to show proof of MARS licensing. They sent me this picture in the form of a PDF. I zoomed it in a lot so you could see it. In the picture the diode is removed. You can cut the solder leads with a razor or thin knife.
     Topic: IC-746 improved AGC and weak signal volume
    IC-746 improved AGC and weak signal volume [message #13] Wed, 29 December 2004 01:47
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    In the service manual under 5-4 RECEIVER ADJUSTMENT.

    For setting the RECEIVER TOTAL GAIN.

    Part 1 follow as written.
    Part 2, set R761 for 178mV (-15dB).

    This gives a better(lower) AGC knee signal level and during weak signal reception maintains good volume level without having to manually advance the volume control. This is especially useful for Six and Two metre weak signal work.

    The noise blanker, general AGC action and S meter calibration were not adversely affected.
     Topic: IC746:Using 500Hz filters on SSB for Dig Modes
    IC746:Using 500Hz filters on SSB for Dig Modes [message #12] Wed, 29 December 2004 01:45
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    Hi there!

    I ran usually my old TS440S-AT with 500Hz IF filters on USB mode for the Pactor lev 1 and 2, and for PSK31 very weak signals.
    Some week ago I found in a Ham fair an FL100 CW filter for the IC746 at a bargain price, and in the last days it happened to me to have some time to devote to our hobby, and so I installed the 9 Mhz IF filter for 500Hz, FL100, on the IC746 for pactor 1 and 2 and psk31, as I am used to.

    I followed the instruction on page 78 of the ICOM user manual.
    After returning all the covers on, I went to page 60 of the instruction manual, to select the installed filter for the 9MHz-1 position.
    I selected the FL100 . Then I went on page 42 for filter program mode setting as suggested on the page 60.
    Note on the top of page 42, at the beginning of the chapter 5-11, 1st paragraph: \" Optional filters ....omissis...
    .. Filters can be independently selected for each operating mode.\"
    And so I went to program mode setting and pushed the \"filter\" button for 2 seconds and then choosed to program the CW and the SSB-Narrow for 9M on 500Hz and 455k for 2.4 k ..... but - surprise - the FL100 was not available on SSB!

    I suspiciously read carefully the manual and find nothing on selecting filters depending from mode choosen..... or relation between filter type and/or bandpbass sensing... nothing. So I went to the usual \"dirty trick way\" to gamble with the filter program mode setting: I told the IC746 that the installed filter was an SSB Narrow 1.9kHz one, the FL223 type. All OK , hi hi ....

    Then I went again on the procedure of page 42, and set the SSB-N filter mode for 9M \"1.9 kHz\" (hi!) and 455k at 2.4kHz.

    It runs OK having now bandpbass of 500Hz on SSB-N mode available for Pactor lev1 and lev 2, and PSK31. On the TS440SAT I had to correct for the IF filter frequency moving the IF bandpbass slightly clockwise to fit it for the selected tone pair (1200-1400 Hz or 1400-1600 Hz) and the same had to be done on the IC746: selecting as usual USB I had to tune the outer larger one of the twin bandpbass tuning about 90 degrees clockwise.
    This proved to be quite a god setting for operation on USB Pactor level 1 and 2 using high tones.

    I tested some lower tone pair compatible with the CW bandpbass (but take care of the CW Pitch setting!!! it should be tuned fully clockwise or you\'ll get no audio out!) and tested with 400-600Hz, 500-700Hz and 600-800 Hz , but although the PtcII controller I use is very versatile on this respect, my ears are not, and so being used to \"by ear search and pre-tuning\" and then \"spectra fine tuning\" I endly went back to the usual 1500 Hz center frequency. I got 1500 Hz as I am also using pactor level3; before it I was using 1300 Hz center.

    Here people using other controllers like KAM+ or alike have to adjust their bandpbass tuning depending on the tones frequencies they use.

    Actually I have not yet the FL52A 500Hz 455kHz filter; if I\'ll find it at bargain price I\'ll buy it and test it;
    I saw by now that having 2.4 kHz bandpbass on 455 kHz works.

    I have to say that apart from this test and related trick to get the 500Hz bandpbass for USB digital RX, I would not suggest asnecessary to buy and install such filters on the IC746 : with the PtcII controller you may work very well on pactor, psk31, rtty and other 500Hz bandpbass modes on the IC746; (do not use the DSP and or NB, NR sometimes\'s good, some others no)

    The same applies for the soundblaster software programs like Digipan or others, the normal bandpbass is more than adequate, and you may taylor it using the twin bandpbass tuning.

    I recommend the narrow filters on TS440sat and alike: more,I suggest on them to replace also the 455kHz filters with other that have better performances (IN-RAD has some good ones) and the old good TS440S will copy nicely and happily very low level digital signals.

    I hope this notes will be useful for some reader, I will appreciate any feedback on this matter.

    Thanks and 73 de I2JJR Augusto
     Topic: IC-746 Backlight Repair
    IC-746 Backlight Repair [message #11] Wed, 29 December 2004 01:44
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    Here you go guys, here is the repair mod for the backlight.

    Remove top and bottom cover.


    Remove the 4 screws holing on the face, 2 on left and 2 on right of face holding it to chbassis. Theres 1 ribbon cable connecting the face to main unit, just pull strait out.


    Remove knobs just by pulling them off. VFO just pulls off also.


    Unplug all ribbon cables on back of face, number them with a permanent marker if you think you might mix them up.


    There is 5 screws holding the top circuit board in, take them out and lift up board, be carefull and feed 2 of the ribbon cables through the board. On the back side of this board there are 2 steel boxes on the board. Take the top off of the biggest one.
    You will see a small square transistor with the #B1201 on it. This is the problem transistor thats been giving backlight problems.

    This transistor has no way of cooling laying flat on the board.remove this at your own risk. You have to have a small tip iron and a good set of eyes and steady hands. The center leg on the transistor is cut off, this is the ground leg, and the top of the trans is soldered to the board.

    Heat the top of the transistor and lift it and it will come loose,then unsolder the legs and lift. Remember which way it came out. Take the new trans and don\'t cut the center leg off, the center leg needs to be soldered where the top of the transistor was soldered. And the other 2 where they were from the start, leaving the part standing up instead of laying flat on the board.

    Now push the transistors side against the metal box and put some heatsink compound around the transistor and between the part and box, now it can keep cool.

    Thats it, put the top back on and put the unit back together. Replacment part #s are NTE2525 or 2SA1244 or 2SB1201, good luck and take your time.

    Works well
     Topic: IC-746 modulation on AM
    IC-746 modulation on AM [message #10] Wed, 29 December 2004 01:43
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    If you want more crisper and louder modulation on AM, turn radio upside down and remove cover at the top right hand corner of radio you will see a varible that says (AM mod). Clockwise increases mod and counter clockwise decreases mod. You might want to use another radio on the same frequency so you can hear results. The radio that you are listening with needs no ant screwed in to it being that you are only listening.

    I have done this and mine has loud crisp modulation. Remember, no compression on AM, you will find that it will muffle you on AM.

    Do at your own risk.

    73s
     Topic: Monitor Audio Output Too Low Icom IC-746
    Monitor Audio Output Too Low Icom IC-746 [message #9] Wed, 29 December 2004 01:43
    root  is currently offline root
    Messages: 192
    Registered: December 2004
    Senior Member
    The monitor function on the IC-746 tends to have low output compared to receiver AF volume, therefore in order to listen to yourself, you have to increase the volume. When the PTT is released back to receive mode, the AF setting nearly blows your speaker or your headphones.

    If the monitor audio output is too low on your ICOM 746, you can add 4.7K resistor in parallel with R1087. This brings up the gain of IC1082 to a more reasonable level that can still be controlled by the monitor level function but with plenty more gain.

    Technical Notes:

    These SMDs are located in the Main Board. You will probably need a service manual to locate these parts on the main board. Adding modifications to these very small parts requires some skill and a good magnifier together with the appropriate tools. A 1/8 Watt resistor will be suitable for this modification, but still require some precision.
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