Issue with Pioneer SX 1280 on AFCI circuit

Discussion in 'Pioneer Audio' started by micaiahm, May 14, 2017.

  1. micaiahm

    micaiahm AK Subscriber Subscriber

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    No. I have tested the receiver both at home and my office with nothing connected. In fact other than when I first brought it back to my office from the tech and everything worked well, I have not connected anything to it and then it was only speakers and my phone to play music.
     
  2. micaiahm

    micaiahm AK Subscriber Subscriber

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    Desolder the PA3004 and re-soldered with 7 pin not connected. 6 second delay happens, but it doesn't sound like a full engage.(the click is shorter)

    Desolder and checked R9 and R10. R9 694k; R10 1.92M. Re-installed.

    Ran out of time...will check these measurements this evening.
     
  3. petehall347

    petehall347 the brandy coffee man

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    AC voltage across r9 with pin 7 still disconnected would be of interest ..should be 700mv . 0.7v AC
    well it may well be higher than that without pin connected
     
  4. micaiahm

    micaiahm AK Subscriber Subscriber

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    From Pin 7 to foil 6.5VAC steady thru cycle.
     
  5. markthefixer

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

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    This is confusing, pin 7 is supposed to be FLOATING, disconnected from the foil it is USUALLY connected to.

    edit TWO: read the whole thread down to my latest post, and JUST find a 1.2 megohm resistor.

    edit: did you connect the red dmm probe to the foil connecting r9 and r10, the black probe to pin 7 and then take a voltage reading? Or do a misread and misreport on a current (amperage) reading? The current through the voltage divider bridge is about 21 microamps (0.000021 Amps), so it won't take much extra current draw from pin 7 to upset the voltage divider bridge.

    Ok, assuming you meant the foil.

    56.3v ac going into a voltage divider: Desolder and checked R9 and R10. R9 694k; R10 1.92M. Re-installed.
    That calculates out to 14.947 volts. Correcting for a 10 megohm dmm yields 14.19v, even assuming a 1 megohm ac voltmeter, it's 9.8v

    since this is all rather offbeat and cobbled together over many sessions, it's not trustworthy.

    Your confidence is precious, and taking the readings should utilize your efforts wisely.
    The resistance readings stand for themselves, but I am forced to assume a lot of things.

    SO, do this EXACTLY:

    I HOPE your meter can read this. There is little chance of damage IF those are the only two points probed on AC amps, so when you finish THAT reading, turn your meter BACK to DC VOLTS.

    Right now I mistrust the PA3004 chip, but am conflicted by earlier reports of your other unit doing the same thing.
     
    Last edited: Jun 5, 2017
  6. petehall347

    petehall347 the brandy coffee man

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    just had a thought and cant remember if it was asked to do all tests with nothing connected to the speaker terminals at all .
    right now if same speakers were being connected to both amps (separate times obviously ) it might well be the problem ...
     
  7. markthefixer

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

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    pete, with q1 pulled, there is NO over current protect.

    but I AM working on a "teary" that is starting to check out.
     
  8. petehall347

    petehall347 the brandy coffee man

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    i suspected the pa3004 earlier . but never like to blame them . failure rate cant be so bad 2 amps in possession of same person go bad . time to do the lottery if so . :D
    this will be something silly as usual . its tracking the the thing down which i am certain you will do .
     
  9. markthefixer

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

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    OK, using the data from the sx-780, sx-980 and sx-1080 designs I was able to calculate an input impedance for pin 7 of the pa3004.

    Treating it as a 19,000 ohm resistor, using 56.3 volts ac into a R10 of 1.92M, R9 is swamped and the voltage at pin 7 calculates out to

    ta daaaa...

    0.552 volts.

    Which is actually a bit low, since they expected pin 7 to have 0.7 volts upon it. BUT the sx-780 feeds that pin a bit more, how much more isn't clear without an ac voltage reading of the transformer. it's around 0.84 volts.

    So, I am going to recommend something completely uncharacteristic for me.
    Change R9 from 1.8 meg ( 1.92 measured) to 1.2 meg. If you wanted to parallel a resistor, that would be a non-standard 3.2 meg to get 1.2meg

    Quite frankly one of my earlier troubleshooting steps went by the wayside, I had asked for the unit to be switched to 110 volts from 120 and see if anything changed, since the pin 7 voltage was low as measured.

    And reverse engineering it went wonky until I figured out pin 7 looked like a 19k ohm resistor to ground instead of a high impedance input.
     
    Last edited: Jun 5, 2017
  10. petehall347

    petehall347 the brandy coffee man

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    i wondered about meter error and blamed it on that . cant always trust the tools even though we do .. both resistors in divider a bit high . r9 also being higher also may well have evened things out a bit . if it is simply meter error .
    i might try a new 1.8 meg first in case its breaking down under load . then 1.2 .. other way round no problem though . perhaps save time that way .
     
  11. micaiahm

    micaiahm AK Subscriber Subscriber

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    Mark,
    You are correct on both counts I misread and misreported. My apologies.
    You guys are now over my head but I love learning. Thanks for your continued patience with me in my ignorance. I wish I could give you both 1280s and let you make them right. My other 1280 is down right now also. The previously mentioned tech gave it back and said there was something wrong with it, couldn't find it and wouldn't fix it. That's another day another project.
     
    Last edited: Jun 5, 2017
  12. micaiahm

    micaiahm AK Subscriber Subscriber

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    I will purchase some resistors and change it out.

    I did change the unit to 110V from 120V previously as you had requested, but I now realize I didn't post that. By the way there was no change.
     
  13. micaiahm

    micaiahm AK Subscriber Subscriber

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    I have changed out R10 to 1.2M resistor. I measured from board pin7 to foil between R9 and R10 and got 10.2VAC steady thru cycle of relay.
    Just to recap: Q1 is still disconnected. PA3004 pin7 is still disconnected and not touching foil.
     
  14. markthefixer

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

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    Sigh, Resolder / reconnect pin 7 to it's foil..
    If the relay pulls in and stays in, reinstall q1 and see if the protect still pulls in and stays in.

    BTW, regarding that current (I.e (micro)amps) reading, well, I gave up, I don't know how else to say it to convey to you to :
    set the meter to amps, which when taking the (electrical microamps) current reading would do the same as connecting pin 7 and allow a functional test while telling ME the number of microamps flowing between the new 1.2 meg resistor and pin 7.



    When taking a voltage reading the meter usually "looks" like a 10,000,000 ohm resistor to the circuit, to avoid affecting it in any way by pulling minimal current from the circuit under test..

    When taking a current (amps) reading, the CURRENT has to FLOW through the meter from somewhere to somewhere - which involves breaking a circuit somewhere - thus why it is infrequently done. By isolating pin 7 I explicitly set those conditions up, where the meter could be inserted into the circuit, both telling me things as well as allowing the circuit to act as if pin 7 had been soldered to it's trace.
     
    Last edited: Jun 7, 2017
  15. micaiahm

    micaiahm AK Subscriber Subscriber

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    Thank you for the explanation I now understand what and why you were asking. Sorry I'm so slow. I know it's late but 46.8v ac.
    I reconnected pin 7 and it still cycles. I am going back step by step thru the posts and remeasuring and testing everything you said.

    So far:
    1. temporarily ground the collector of Q2, to make sure the relay will pull in and STAY in. YES
    2. Q1 gets disconnected, see if relay still cycles, leave disconnected for now. YES
    3. ground pin 4 temporarily, see if cycling stops.[/QUOTE] Now, YES

    I will keep going and post results.

    Thanks again for all the help and patience.
     
    Last edited: Jun 7, 2017
  16. petehall347

    petehall347 the brandy coffee man

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    Location:
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    where did the 46.8v ac appear from ? like where were the meter probes touching ?
    all i can guess is measured across r10 with pin 7 connected ?
    mark wanted you to connect from disconnected pin 7 to the trace where it should connect to .meter set on ac ma and probes plugged into appropriate sockets on the meter .
    current can be calculated by knowing the voltage across the resistor but wont be as accurate as testing with your meter an ac ma . too many variables .
    grounding pin 4 and relay staying in is a bit odd and important . . i have a theory but will mark carry on ... all i am saying now is it might involve r1 r2 . and dc voltages
     
    Last edited: Jun 8, 2017
  17. markthefixer

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

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    please answer things explicitly:
    1. yes relay pulls in and stays in
    2. yes, relay continues to cycle.
    here's the BIG one:

    3. Ground pin 4. EXACTLY WHAT HAPPENS?
    does the relay pull in and STAY IN?

    Thus
    I do not know if, when cycling stops:
    does the cycling stop with the relay pulled IN?
    or
    does the cycling stop with the relay relaxed and NOT pulled in?
     
  18. micaiahm

    micaiahm AK Subscriber Subscriber

    Messages:
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    Location:
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    Sorry Mark,
    Those were my notes and I didn't realize that they had posted. A lot going on this week and I now have to go out of town for the next few weeks. If I don't answer or post it is not because I have lost interest, but I will be in Europe on and off the grid. I will be able to focus on this when I get back I appreciate your loyalty to helping me find the fix.

    Here is the accurate info:

    1. ground Q2 collector. Relay engages and stays engaged.
    2 remove Q1. Relay continues to cycle, no change.
    3. Ground PA3004 Pin 4 momentarily, relay continues to cycle, no change.

    Thanks again.

    Pete,

    Thanks for the response. I did disconnect Pin 7, had the DMM set on maAC. In trying to keep the probe on Pin 7 I probably touched Pin 7 to the board. Sorry for the confusion. I appreciate your help in this also.
     
  19. petehall347

    petehall347 the brandy coffee man

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    23,808
    Location:
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    so you measured milliamps and wrote volts ?
     
  20. micaiahm

    micaiahm AK Subscriber Subscriber

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    Ok all. I'm back and ready to tackle this. Thanks for your patience.

    Yes. It was mA and I typed volts.
     

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