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IC Chips needed for SX-1280

Discussion in 'Pioneer Audio' started by Jondubb35, Jun 10, 2017.

  1. Jondubb35

    Jondubb35 New Member

    Messages:
    5
    Hello-

    I'm in need of the near impossible to find IC chips for my Pioneer SX-1280. Any AKers out there have any and are willing to sell?

    Parts are PA1001A and PA1002

    Thanks all
     
    Last edited: Jun 10, 2017
  2. zebulon1

    zebulon1 Into Phase Linear's lately Subscriber

    Messages:
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    Location:
    Las Vegas Nevada
    Others may ask why you may need the chips but I'll give a source. Ebay for the PA1001A. Their from China but I've had good luck with them. Only had bought a few but all worked well.
    The PA1002 is a different story. Never tried one from China and they want $30.00. Ouch!
    You might find a donor tuner board on eBay that has the chips. I'm sure you've looked into it. Managing the cost is a concern.
    Also the chips are found in other manufactures receivers.
     
  3. Jondubb35

    Jondubb35 New Member

    Messages:
    5
    Thanks! I saw those PA1001A's from China on eBay but I wasn't sure they would work since there's really no description. I will order a couple of those. I do have an SX-780 and an SX-980 with similar looking chips. Do you know if these are the same as what's used in the 1280s?
     
  4. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

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    Rarely do both die, and we call the PA1002(a) "unobtanium". It's an op-amplifier muting chip that acts like a protect circuit. The PA1001 is a stereo decoder.

    Pray tell, enlighten us on their demise and your need.
     
  5. Jondubb35

    Jondubb35 New Member

    Messages:
    5
    Well, I'm not exactly sure what's causing my issue, to be honest. Based on my "Internet forum" research I thought maybe the chips were the root of my problem. The receiver sounds great and operates well except for the tuning meter. The meter dial seems to be stuck straight up in the middle. It never moves, even when I'm rotating the dial, it's frozen. FM seems to work fine and I can tune in stations, it just makes it a little more difficult to fine tune since the tuning meter doesn't move. The signal meter operates perfectly. I swapped out the meter with another from a donor unit that was in great cosmetic shape and it didn't fix the problem. Still stuck directly in the middle. Any ideas?
     
  6. zebulon1

    zebulon1 Into Phase Linear's lately Subscriber

    Messages:
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    Clip the meter leads to the tuning meter and select DC mv's. Tune in and out of a station slowly and see if the DMM mV's responds to the tuning. You'll see what's going on and get a feel if the board/chips are working.
     
  7. Jondubb35

    Jondubb35 New Member

    Messages:
    5
    Thanks. We just tried this with both of the tuning meters. The original one and the replacement I got from a donor unit. Not moving. Tuning dial stuck in the middle. Signal meters work great and radio works. What actually controls the tuning meter?
     
  8. txturbo

    txturbo AK Subscriber Subscriber

    Messages:
    704
    Location:
    Austin, TX
    If the chip were bad that drives the meter it would be a PA3001A on an SX-1280. You can see a data sheet for it here.

    Since you have already tried another meter I assume that the meter is not the issue. Since T6 is critical for tuning to function and you have stated that it tunes in fine I would guess that the IC is the problem. It is possible that T6 is so out of tune that you will not get meter deflection but it's a long shot.

    Check the voltage at pin 7 on the PA3001A compared to the schematic. If it is the chip it's super cheap, under 4 bucks.

    [​IMG]
     
  9. zebulon1

    zebulon1 Into Phase Linear's lately Subscriber

    Messages:
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    Location:
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    The tuning meter is the meter that shows a stereo signal when in the full 12:00 position.
    It is switched through the FM function switch and turned off when AM is selected.
    The FM push button may only need a good Deoxit cleaning.
    Try exercising the FM switch multiple times and see if you can get the meter to work. If it does it will still need cleaning.
    With FM selected you could use jumpers from the pins on the board (Pins 27 and 28) to the meter, bypassing the switch.
    Or clip your meter (DMM in DC mV's) to the tuner board pins directly and report what you see when tuning in and out of a good strong station.
     
    Last edited: Jun 10, 2017
    txturbo likes this.
  10. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

    Messages:
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    Location:
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    Clip the DMM set for millivolts DC across pins 27 and 28 of the tuner.

    It IS most likely the switch, but there are some meters that lose contact at their pivot point.
     
  11. Jondubb35

    Jondubb35 New Member

    Messages:
    5
    Thanks all for the help with this. Unfortunately, I'm traveling for work this week (Sun-Weds) and I won't get an opportunity to work on it until I get back Wednesday evening. I will report my findings and/or progress once I'm home and able to get back to back in the music cave. Damn job getting in the way of important stuff! :rant:
     
    Last edited: Jun 11, 2017
  12. bd1886

    bd1886 Super Member

    Messages:
    3,083
    Location:
    Puget Sound/Cascade Foothills
    The Onkyo TX-x500 MKII's top two receivers can't be considered sleepers anymore. Time will tell how our own group's learning will effect other "sleepers" too but, the TX-8500 MKII and TX-6500's have exited the original "fog". 2012 posting (things have changed) and people have woken up.....not these "sleepers".

    Premium classics they are.
     
    Last edited: Jun 11, 2017
  13. SicMan

    SicMan Fire up those speakers

    Messages:
    2,953
    Location:
    Wolcott - CT. USA
    This thread is about an SX1280 Pioneer you are hi-jacking this thread. Thanks for your info.
     
    bd1886 likes this.
  14. bd1886

    bd1886 Super Member

    Messages:
    3,083
    Location:
    Puget Sound/Cascade Foothills
    Sure did! Apologies folks.
     
    SicMan likes this.
  15. SicMan

    SicMan Fire up those speakers

    Messages:
    2,953
    Location:
    Wolcott - CT. USA
    Thank you. bd1886 for understanding.
     

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