Help fixing old Realistic Concertmate

Discussion in 'The Projects Forum' started by Pants Jackson, Aug 6, 2012.

  1. Pants Jackson

    Thread Starter New Member

    Aug 6, 2012
    I recently purchased an Realistic Concertmate 12-1467 Stereo Radio/Receiver. It is really quite a nice piece, and I really would like to see if I can fix it.

    Let me explain the situation. When using the speakers, the right channel sounds really messed up, garbled and quite a bit quieter then the left channel. I already tried swapping speakers, it is definitely the receiver's fault. When using headphones the right channel fares much better, there is a low sort of humming in the right channel, but when music is playing you cannot hear it, but when there is a break in the music it is quite annoying indeed. I should also note that for it to sound balanced, I have to put the balance more then slightly toward the right.

    As far as the inside, I've given it a good inspection, and can find nothing visibly wrong with it. All the capacitors look pristine, and the boards all look just fine. I can post some pictures if that is helpful.

    I have never repaired anything audio related before. I was really hoping someone could at least put me on the right track, as to what steps I should take, or even what questions to ask. Thank you so much for your time.
  2. bertus


    Apr 5, 2008
  3. Pants Jackson

    Thread Starter New Member

    Aug 6, 2012
    What kind of measurement equipment did you have in mind?

    Here are my best attempts to photograph the unit

    The second picture is of the board I think does the amplification, but I am expert on audio equipment..

    The inside is difficult to photograph since it is all rather delicately crammed inside. I am still trying to figure out how to take it all out if I have to.

    Thanks for the reply! I appreciate any help
  4. Skeebopstop

    Active Member

    Jan 9, 2009
    You are in luck because your left channel works! Let us use our reverse engineering practices and principles:

    1. There is a noticeable difference and thus there should also be in the circuitry.
    2. Start measuring node impedance on right channel and compare to left (shouldn't be any large differences, if there are, that is likely your problem)
    3. Replace all circuitry on the right channel in the vicinity of the impedance mismatch based on the circuitry of the left
    4. Trial and repeat

    You might find it easier to reverse engineer the circuit diagram from the left channel and see if some 'powered' results can't assist you.

    Good luck!
  5. t06afre

    AAC Fanatic!

    May 11, 2009
    How old is this unit. If it is in range 15 to 20 years old. I would consider replacing all the electrolyte caps as a start