issue with AKAI AA-1030 Receiver

Discussion in 'DIY' started by rotco, May 17, 2018.

  1. rotco

    rotco Member

    Messages:
    76
    back to the rx.
    i gave it another cleaning...really deep one... deoxit everything.. especially the selector switch which was felt to me a bit "sticky", and the volume knob which felt to me like "Lack of continuity".
    (btw, when i encounter a really dirty one and sticky, i give it a heat with a hair dryer fan, and after that i deoxit it. it turned to be really effective).
    i let it 24h to dry since i use oily deoxit with lubricant.

    from first operation (it was late at night i couldn't really go deep into what you recommend me yet... just turned it on to see if the cleaning helped).

    and i feel like the explosion noises got really less worse, only when i got about around +80% of the volume... (before i thing it happens already in 40%).
    but, what i realize now is... that it might just not amplifying!
    try to say... that i turned the volume up to approx. 80%... and the speakers makes only a low volume..
    so.. might it means that there is an issue with the Power Amp level? and the only reason i still got music thru the speakers its because of the Pre amp board? (i used i really cheap headphones also... they were felt like they having the same behavior as the speakers)

    if so.. how can i continue from here?
    @mbz - i checked if the bass frequency has a special effect.. and it didn't feel like that. plus, i tried to "play" with mono/loudness switches... also, no special effect.

    for the fuses i said they are in parallel. sure i was wrong! just wrote it and i knew i was wrong.. they are just lying one parallel to the other.

    for the Scope... i don't really need lots of room on my desk... i'm using a laptop.
    do i really need to do all this precautions? the device itself hasn't have the protective components in it? do i really need to make a DIY protection?
    what's the connection to my sound card?
    the Scope is only connected thru USB.
    (it's only a hobby... i really don't want to but a scope higher then 60 bucks...as long as i can purchase this one with reasonable price)

    from the computer (or actually my cellphone) i hoped to insert the audio signal from a basic free "signal generator" app.

    p.s
    thru this quick basic operations.. i notice also that the high frequency filter switch isn't reacting at all. (the low frequency filter did it's job..
    i guess it cannot affect now.. and i will deal with it later after the receiver will back to life... hope so
    (maybe it's just an old capacitor in the filter board)
     

     

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  2. rotco

    rotco Member

    Messages:
    76
    Btw
    I finally got the "special" ccapacitor for making myself an Audio Test Probe.
    Maybe i can start with it and wait with the O-Scope.

    Is there any thing i should be aware of while using it?
    May i use it wherever i want?
    Or maybe after the amp section while the signal is amplified, i need to prevent using it there? (Or even in the speakers terminals output)

    What about the p.s?i can guess it's a circuit without a sound signal... Only electricity?
    Ao i won't be able to find something there.. But..is it still safe to try there?

    Sonce probably i wont know each point what is it exactly.. And might want to try "free" any point i see.

    (Ofcourse i will track the route thru scheme, but in case i have a mistake)

    Thanks
     
  3. mbz

    mbz AK Subscriber Subscriber

    Messages:
    1,898
    Location:
    Melbourne, Victoria
    I use a software package that uses my PC soundcard, my cro's/tektronixs need a restore. The sound card needs to be
    protected from excessive voltage otherwise it can be damaged. A series capacitor should be connected to block dc voltage, maybe 10nf or smalled?
    A voltage divider should be considered if you are measuring large audio signal, ie, at the speaker posts. Typically a 1/10th divider is used, ie a 1 ohm
    resistor in series with a 9 ohm resistor, measure voltages across the 1 ohm resistor. You only need the divider if you are measuring at the spkr posts.
    The blocking cap is a must have.
     

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