Connect with us

Panasonic SA-AK45 to audio amplifier

Discussion in 'Troubleshooting and Repair' started by Edgars, Sep 5, 2014.

Scroll to continue with content
  1. Edgars

    Edgars

    5
    0
    Sep 4, 2014
    Hy! I have some old parts of the music center (Panasonic SA-AK45) laying around, and I thought if it's possible from these components to create an audio amplifier, so that I can input some audio signal from computer direct to amplifier, and then output to speakers.
    I connected transformer with power circuit. At the beginning it seemed that transformer is working properly, but when measuring voltage on the main chip, there was nothing. Then I shorted out transistor Q505, which drove the relay. And then on the main chip appeared some voltages. After that I tried to input audio signal from computer to the Left and Right channel. Adding some little test speakers I could hear same signals, but the signal was about as strong as the computer gives, there was no amplification. So I don't know what to do next, perhaps there's still some control signals. I would like to ask for your help. I added schematics of power circuit. 2014-09-05 14.31.06.jpg 2014-09-05 14.31.32.jpg
     

    Attached Files:

  2. Angelo

    Angelo

    30
    2
    Sep 10, 2014
    Well, do you have a scope ? I would be sure all the power supplies are present on the aplifiers (see the datasheets), then i would look at the signal (amplifier input and output) with the scope.
     
  3. Edgars

    Edgars

    5
    0
    Sep 4, 2014
    569400-page-001.jpg I'm sorry, but I do not have a scope. maybe you can look ar this full user guide here: http://files.fm/u/gcnuzoo usefull information about power circuit on page 43 and maybe it will make more sence on page 52 (block diagram). I added new picture, where I drew few things, I want to make sure if I do everything properly. And I think that something have to do with that headphone switch.
     
  4. Angelo

    Angelo

    30
    2
    Sep 10, 2014
    From a first look i see you should supply all those
    +/- 54 V
    -/+ 48 V
    -22 and +26.5
    Once you are sure these voltages are there (tester on those HYBRID IC's pins), i would check on the MSR308 datasheet if there are some feedback / control pins to set to some level.
     
  5. Edgars

    Edgars

    5
    0
    Sep 4, 2014
    Tested thoes leeds, there was a bit higher voltages then shown in schematic.
    +/- 58 V
    +/- 49 V
    etc...
    All other pins was supplied with voltages (also a bit higher then needed) as shown in schematic, only pin 11 (DISP HUMT) and 15 (RELAY) was around at 0V.

    I was searching datasheet on the RSN308 power amp, but cant find any usefull information :\
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-