High Power FM Transmitter

Discussion in 'General Electronics Chat' started by R!f@@, Aug 8, 2012.

  1. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    8,750
    759
    U know I told u guys we have all kinda weirdo's trying to be professionals just by tinkering and no theory. !

    I am beating one by one and I am loving it. :D

    OK, this thread is about two 700W FM transmitter units that came in for repair. These things are old school ones.

    The two Tx from front

    [​IMG]

    Since I took the picture together and am messing with the two simultaneously, the posted pictures will have label "A" and "B". Meaning Tx A and Tx B.

    If one photo is labeled "A" supply means the picture is from the top transmitter which I will refer to as "A" and bottom one is "B"

    PS...I might get confused so bear with me if I did and do tell.

    This is the top cover removed of "A"

    [​IMG]

    "A" Modulator

    [​IMG]


    A

    [​IMG]
     
    Last edited: Aug 8, 2012
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,004
    1,525
    Loosie will help you to not get confused. You know how good he is at that. :)
     
    strantor likes this.
  3. #12

    Expert

    Nov 30, 2010
    16,261
    6,770
    Get a black marker pen and put a big, "A" or "B" on the shields and other sheet metal.
     
  4. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    8,750
    759
    My PC is acting up again. Freakin windows.

    Takes minutes to refresh.
    So fresh installation done.
    Rest of the pics are being uploaded.
    Work is in progress.
     
  5. #12

    Expert

    Nov 30, 2010
    16,261
    6,770
    Don't blame the operating system. There's probably a loosewire in there, somewhere.
     
    shortbus likes this.
  6. nerdegutta

    Moderator

    Dec 15, 2009
    2,515
    785
    Or it's an EBKAC...
     
  7. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    I trust you have an adequate SWR, & balanced dummy load antenna to fire those puppies into !!!
     
  8. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
  9. MrHam

    New Member

    Jul 20, 2012
    10
    0
    What is the frequency?
     
  10. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    8,750
    759
    97.0Mhz

    These were used to broadcast peoples thoughts. Suddenly SWAT came and everything went to scrap.

    That is what we call friggin freedom of free speech during Gayoom's rule
     
  11. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    In that case, you have a very powerful tool there. One of probably very few mediums to spread seeds of revolution and promote free thought. In your situation, these 2 FM transmitters potentially carry the weight of several human lives, or even the future of every person in your country.

    Now all you need is an antenna and a martyr.
     
    #12 likes this.
  12. #12

    Expert

    Nov 30, 2010
    16,261
    6,770
    I volunteer R!f@@ :D
     
  13. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    as the antenna or the martyr?
     
    R!f@@ and #12 like this.
  14. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    8,750
    759
    Here is the inside of second "B" one

    [​IMG]

    [​IMG]

    Failed attempt to fix B x board

    [​IMG]

    Failed B PSU

    [​IMG]
     
  15. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    8,750
    759
    Now believe or not I knew that the Tx module won't have enough heat sink applied. :D

    And now see for urself

    [​IMG]

    Am I a genius or what ?

    The antenna coupler is not how it's supposed to be

    [​IMG]

    I worked on the Tx module first. Remind u tht this is a new board they bought cause they could not fix the first one and it ended up fried working at 50% of it's rated power. I say this cause the PSU in it is under rated for the original 700W new module.

    [​IMG]

    And hence the burned components

    [​IMG]

    trying to source them now.

    So now I need a working PSU.
    The B one is in good condition but faulty. I figured this one atleast has higher power than the replaced one so I thought I will fix it and check.

    Work is in progress. Pics coming soon on next post
     
  16. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    8,750
    759
    Photo's are for reference so I know which wire goes where.

    But I thought I'll share with u all since u all have been so good in class.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    I found the fault or rather faults.

    Work is postponed till I get the new parts from abroad.

    Till then tata.
     
Loading...