A A A
Avatar

Please consider registering
guest

sp_LogInOut Log In sp_Registration Register

Register | Lost password?
Advanced Search

— Forum Scope —




— Match —





— Forum Options —





Minimum search word length is 3 characters - maximum search word length is 84 characters

sp_Feed Topic RSS sp_TopicIcon
MARS/CAP Mod completed for the YAESU FT-7900R
sp_BlogLink Read the original blog post
Topic Rating: +2 Topic Rating: +2 (2 votes) 
June 17, 2010
12:33 pm
Avatar
stang5_0
Phoenix, AZ

Admin
Forum Posts: 80
Member Since:
June 13, 2010
sp_UserOfflineSmall Offline

I have completed this mod personally, and am pretty sure you can do it too!  🙂

In fact, I know you can!

Check out the thread I started HERE in the FORUMS and lets talk about it if you want. This mod will allow for 136-174 & 420-470 MHz Transmit Operation with only a small amount of your time.  I have also confirmed this with the The Family Radio Service (FRS) set of radios I have.  In fact, I've already got the freq set in memory.

Life is good, so go for it.

Stang

Music washes away from the soul the dust of everyday life.-Berthold Auerbach (German author, 1812 – 1882)

July 15, 2010
4:23 pm
Avatar
BClough
Guest
Guests

Can you please e-mail the steps to do the modification? i saw it on here a few months back and cannot find it now. any help would be greatly appreciated! thank you!

July 15, 2010
5:28 pm
Avatar
n7hwa

Moderator
Moderators

Members
Forum Posts: 8
Member Since:
June 13, 2010
sp_UserOfflineSmall Offline

Well I've always told folks that if it's electronic, I'll hack it.  My friends, that's just what I did this evening.  I have successfully performed they Yaesu FT-7900R

MARS/CAP Modification for 136-174 & 420-470 MHz Transmit Operation.

Rather then re-invent the wheel with pictures and all that crap, please allow me to provide you with the information I used to complete this mod. 

*Please note – it takes a steady hand because what you are dealing with is actually much smaller than what the pictures lead you to believe.  And now without further delay, here are the steps taken:

Author: Wiley WA5OTR

Article in its original form can be found at http://mods.dk/view.php?ArticleId=4520

Disclaimer

I do not claim that this mod will work

for you. It worked only for me on the one radio I own. If you are

unsure of what you are doing, DO NOT ATTEMPT THIS MOD! You make the mod

described at your own risk and I cannot be held responsible in any way

for how this mod will work on your radio.

Remember, it is against the law to use

this radio on any frequency other than those authorized by your class

of license. This radio is NOT FCC type accepted for any radio service

other than the Amateur Radio service.

Steps for making this mod. I had to use a large magnifying glass the

whole time I was working on this radio. These parts are extremely

small so be really careful!

  1. Make a backup of your programming before doing the mod.  You will loose all previous programming when you turn the radio on
     

    the first time after making the mod and you will need to reprogram your radio.

  2. DISCONNECT THE POWER CORD!

     

  3. With the radio facing toward you, remove the eight screws holding the top cover, lift the cover off and disconnect the speaker.
     

    Image Enlarger

  4.  

  5. With the radio still facing toward you, look in the front left hand corner (corner closest to your body), you will see the microprocessor.
     

    Image Enlarger

  6.  

  7. To the left of the processor, there will a row of eight (8)jumper solder lands on the main board
     

    Image Enlarger

  8.  

  9. With the radio still facing toward you, there will be two extremely small, black jumpers soldered across onto the main board. The jumper that must be removed is the jumper closest to the front of the radio. The blue arrow points to the correct jumper.
     

    Image Enlarger

  10.  

  11. I used a 7.5 watt pencil iron from Radio Shack with the tip shaved to a very fine point and it was still about 4X larger than I
     

    needed. After I unsoldered the ground side of the jumper and then proceeded to accidently break the trace on the high side of the jumper,

    the thought occurred to me that it probably would have been easier to just cut the trace on the high side of the jumper! That will be up to

    you and I have not specifically tried doing it that and leaving the jumper soldered to the board.

    Image Enlarger

  12.  

  13. Reassemble the radio, hookup power, and turn on the radio.
     

    The display will momentarily totally light up as the radio performs an automatic CPU and memory reset. When a frequency is displayed, hook the radio to a dummy load and check your transmit range. Reprogram your radio accordingly.

You have now completed the extended transmit frequency range for the FT-7900.

A great article indeed, and as I mentioned, I followed it and am able to communicate with my family set of radios.  It was quite easy.  I lightly touched the tip of the iron to the left side of the jumper watching it under the magnifying glass until I saw the solder give way.  I then lightly worked it a little with a screw driver and popped it off.

Now as the author mentions, you will lose ALL programming, so if you have the means to backup your radio, I suggest you do it.  I only had a handful of frequencies in there anyhow so it didn't much matter to me.

If this makes you nervous, let me know, perhaps I can do it for you or discuss it further with you.

Again, please save yourself the trouble and follow this doc.  You don't need to look anywhere else.  Enjoy your new capabilities,

groovy

Stang

The following users say thank you to n7hwa for this useful post:

stang5_0
July 15, 2010
5:57 pm
Avatar
n7hwa

Moderator
Moderators

Members
Forum Posts: 8
Member Since:
June 13, 2010
sp_UserOfflineSmall Offline

The photo alignment is kinda whacked above.  I'll see about cleaning that up but if you follow the blog link it's cleaner.

August 27, 2010
11:54 am
Avatar
Richard{KC9QBB]
Palmyra,Indiana

New Member
Members
Forum Posts: 1
Member Since:
August 27, 2010
sp_UserOfflineSmall Offline

clapstang5_0 said:

I have completed this mod personally, and am pretty sure you can do it too!  🙂

In fact, I know you can!

Check out the thread I started HERE in the FORUMS and lets talk about it if you want. This mod will allow for 136-174 & 420-470 MHz Transmit Operation with only a small amount of your time.  I have also confirmed this with the The Family Radio Service (FRS) set of radios I have.  In fact, I've already got the freq set in memory.

Life is good, so go for it.

Stang

 I am going to do this tommorow I will let you know THANKS!!!!!!!!!


September 2, 2010
10:55 am
Avatar
n7hwa

Moderator
Moderators

Members
Forum Posts: 8
Member Since:
June 13, 2010
sp_UserOfflineSmall Offline
6sp_Permalink sp_Print
+1

Greetings Richard and welcome!

I thought I would check with you and see how this worked out for you or if you even got a chance to try yet.

The critical thing, make sure you use the finest point iron you can.  I went out to Ace a spent the $10 or whatever it was and got one just for this.  I didn't want to take a chance a ruin the board.

 

N7HWA

The following users say thank you to n7hwa for this useful post:

stang5_0
August 28, 2011
9:20 am
Avatar
Solong
Guest
Guests

How can I mod the 7900r to transmitt on 118-136

August 29, 2011
5:58 pm
Avatar
n7hwa

Moderator
Moderators

Members
Forum Posts: 8
Member Since:
June 13, 2010
sp_UserOfflineSmall Offline

I'm not sure that has been done on this rig before.  Somebody please, if I am wrong correct me.

73's

N7HWA

September 4, 2011
9:14 pm
Avatar
DaveC
Guest
Guests

Safe to assume transmit is FM only, not AM?

Thanks.

August 21, 2012
10:24 am
Avatar
Mark
Guest
Guests
10sp_Permalink sp_Print
0

Any way to modify the receive to go down to 42 MHz?

June 9, 2014
11:20 am
Avatar
Cor, PA0GTB
Guest
Guests
11sp_Permalink sp_Print
0

thanks for your discription about this modification
I own a Yaesu FT 7900E (europe model)Notice USA is FT7900R

Standard the 2 meter bands is 144-146 Mhz and 70 cm 430-440 Mhz
I like to know if this mod also will work on a Yaesu FT-7900E version
Because i like to use the part 446-447 Mhz to use our PMR channels on this rig

73, de Cor
PA0GTB

June 9, 2014
11:26 am
Avatar
stang5_0
Phoenix, AZ

Admin
Forum Posts: 80
Member Since:
June 13, 2010
sp_UserOfflineSmall Offline
12sp_Permalink sp_Print
0

I do not have any info on the 7900E.  Did a quick search on Google and did not find anything either.  Not sure what differences there would be in this case.

Music washes away from the soul the dust of everyday life.-Berthold Auerbach (German author, 1812 – 1882)

Forum Timezone: America/Phoenix

Most Users Ever Online: 31

Currently Online:
2 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Members Birthdays
sp_BirthdayIcon
Today None
Upcoming None

Top Posters:

Jim: 3

Dissertation Eden: 1

Richard{KC9QBB]: 1

Essay Writing Reviews: 1

Member Stats:

Guest Posters: 6

Members: 22

Moderators: 1

Admins: 1

Forum Stats:

Groups: 4

Forums: 13

Topics: 41

Posts: 100

Newest Members:

inetryconydot, Essay Writing Reviews, Dissertation Eden, bobcat1

Moderators: n7hwa: 8

Administrators: stang5_0: 80