Open Transmit Icom IC761

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bluemeanie
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Open Transmit Icom IC761

#356546

Post by bluemeanie »

Hi
Finally decided to unlock the general coverage receiver on the Icom. On a couple of searches found links that said all I have to do is cut R37 on the marker unit under the bottom cover. Did that and the unit still works as before but will not transmit in the general coverage receiver mode. Any ideas or help will be appreciated.
Thanks Mark
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Re: Open Transmit Icom IC761

#356547

Post by redlght »

I found this:
IC-761 ACTIVATE TUNER WHEN IN GENERAL COVERAGE MODE

Remove the top cover of the IC-761 and locate the tuner band switch unit
PC Board which is the 2nd small PC board located behind the antenna tuner
preset unit. On the board, locate J 7 and at that location, you will note
a three (3) pin molex plug with a black, brown, and red wire connected to
it. Either unplug, remove, or clip the center brown wire coming from the
plug. Carefully unplugging the wire and placing heat shrink tubing over
the end works very well. This enables the tuner to be activated on GENERAL
as well as the ham bands.

TX inhibit may be activated if the tuner can not function in out of band mode.
Last edited by redlght on March 30th, 2014, 2:35 pm, edited 1 time in total.
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Re: Open Transmit Icom IC761

#356549

Post by bluemeanie »

Thanks but that's to activate the Auto tuner in the radio and not get the radio to transmit in general mode. don't need the tuner in fact don't use all the time on the hf bands. So we need to keep looking. Thanks Mark :idea:
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Re: Open Transmit Icom IC761

#356550

Post by redlght »

With out looking at the schematic tx is normally cut off by a logic chip applying voltage to a bias transistor when out of band mode enabling the tuner in out of band mode may disable tx inhibit. TX inhibit may be activated if the tuner can not function in out of band mode and only allow RX out of band. You can re-solder wire back together if that does not work for you.

Sunday, 30 March 2014, 13:51 PM

also can try to rest the cpu:
Hold [M-CLEAR] button and turn the radio on.
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Re: Open Transmit Icom IC761

#356552

Post by MDYoungblood »

I am positive that if the radio has the tuner you have to do both or it will not transmit of the General coverage Receiver.

http://www.hampedia.net/icom/ic-761.php

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Re: Open Transmit Icom IC761

#356553

Post by bluemeanie »

Tried the rest. That didn't work. What the heck will enable the tuner. The other sites just said to cut the resistor but what the heck cant hurt it(I hope).
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Re: Open Transmit Icom IC761

#356554

Post by redlght »

No it can not hurt but easy to redo, some times if the auto tuner can not operate the radio enables the TX inhibit and will not TX to save the radio.
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Re: Open Transmit Icom IC761

#356556

Post by bluemeanie »

OK Did the tuner mod. Still won't work in general mode. Radio works as advertised in reg HF mode. OK really lost now.
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Re: Open Transmit Icom IC761

#356557

Post by redlght »

If you got the right resistor cut and did the rest and a reset i am stumped
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Re: Open Transmit Icom IC761

#356558

Post by bluemeanie »

the resistor was clearly marked R37 the only other one was R39 and there is no reference to that. so beats me radio still works so haven't destroyed it yet but there's still time.
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Re: Open Transmit Icom IC761

#356559

Post by redlght »

Well you did it all this is the only thing i could find as you did.
Image
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Re: Open Transmit Icom IC761

#356560

Post by bluemeanie »

OK thank you all for the help. The picture did the trick. You have to cut the R37 on the little board NOT on the main board. was able to solder that back together. Guess that's why I am a mechanic not a technician. Thanks again Mark
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Re: Open Transmit Icom IC761

#356561

Post by redlght »

Glad you got it going then congrats!
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Icom IC761 is locked

#385678

Post by gary67 »

When I turned my 761 (in Red it said LOCKED). why did this happen?
To unlock it I have to Hold [M-CLEAR] button and turn the radio on. Where do I find the [M-CLEAR] button?
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Re: Icom IC761 is locked

#385679

Post by MDYoungblood »

gary67 wrote: June 10th, 2017, 1:51 am When I turned my 761 (in Red it said LOCKED). why did this happen?
To unlock it I have to Hold [M-CLEAR] button and turn the radio on. Where do I find the [M-CLEAR] button?
Hello gary67,
Welcome to the forum. My guess is the backup battery finally died so it will need to be replaced. If you don't have a manual for the radio one can be easily downloaded off the internet for free. Changing the battery isn't hard. The "M-clear" button is the center button between the 4 knobs on the right of he display, I believe is reads "Clear".
As a new member to the forum could you post an intro in the "Welcome to the Forum" topic, click here; http://www.cbradiotalk.com/viewforum.php?f=89 , so others can say "Hi", thanks.

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Re: Open Transmit Icom IC761

#386298

Post by jon6667 »

i would like to do it to my kenwood.
but not liking the smd components. to much heat.= big problems
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Re: Open Transmit Icom IC761

#386299

Post by MDYoungblood »

jon6667 wrote: July 12th, 2017, 11:54 am i would like to do it to my kenwood.
but not liking the smd components. to much heat.= big problems
Make a post and the model of your Kenwood. Most MARS mods you don't need to unsolder the SMS component, a exacto knife can be used to cut the solder joint.

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Re: Open Transmit Icom IC761

#386303

Post by jon6667 »

its a kenwood ts 2000
thanks.
don't know if i want to do it. my eyes are not what they used to be.and its a almost new radio. less than 1 year old
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Re: Open Transmit Icom IC761

#386304

Post by MDYoungblood »

I have done the MARS mod to a couple of my radios but have decided not to do it to any newer radios I purchase in the future unless it becomes necessary.

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Re: Open Transmit Icom IC761

#386310

Post by jon6667 »

mine is a virgin. never had the covers off. i think ill leave well enough alone
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Re: Open Transmit Icom IC761

#386729

Post by jon6667 »

i unlocked my 450d because stock you only get 4 frequencies on60 meters it.
real simple mod. now i can transmit on all of 60 meters not just 4 freq.
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Re: Open Transmit Icom IC761

#386754

Post by bluemeanie »

very nice
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Re: Open Transmit Icom IC761

#386757

Post by MDYoungblood »

jon6667 wrote: August 10th, 2017, 11:24 am i unlocked my 450d because stock you only get 4 frequencies on60 meters it.
real simple mod. now i can transmit on all of 60 meters not just 4 freq.
Just remember there is a restriction on 60m and only those 4 frequencies can be used legally.

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Re: Open Transmit Icom IC761

#386766

Post by jon6667 »

what can i say. i'm a outlaw. trick is not
getting caught
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