recapping sx-850 for my son

Discussion in 'Pioneer Audio' started by nackesww, Mar 22, 2018.

  1. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    I've been enjoying my new hobby into electronics. It doesn't matter what new thing you try, its overwhelming until the pieces start coming together.
    I was visiting my son and while he had the music playing in the background I couldn't help but notice the crackling noises coming from the speakers. I recapped the HPM 100 speakers he had and when I had them hooked up to my system at home they sound great. But when I hooked them up to his SX-850 they didn't sound as good. So after I heard the crackling noises I told him I would recap receiver.
    After pouring countless hours on videos and posts I ordered all the parts and started recapping. Every time I would get done recapping a board i would turn it on to make sure it would work and to see if there were any improvements.
    This is where I'm at right now after recapping and replacing transistors.
    These are competed:
    AWF-011
    AWR-101
    AWS-099
    AWS-093
    AWS-094
    AWF-011
    AWM-062
    After replacing the transistors in AWM-062 It all seem to be working good until the next day when I was going to start on the power amplifier assembly. I went to turn it on and the lights came on but no click from the relay, and sure enough no sound.I did take out the transistors and put the old ones back in and it didn't help.
    Like I said before I'm new at this so please bear with me. Looking at the schematics and testing the leads with my DIMM I would say I should move on and recap the power amp, but before I do I would like to run this by all of you first and hopefully get some expert advice.
    Hear are the values I got from test:

    AWM-062 protection circuit
    1. .02
    2.-13.30
    3. 0
    4. 0
    5. .01
    6. .03
    7 .01
    8. 0
    9. 36.94
    10. 36.94
    11. 36.95
    12. 7.9 AC

    AWR-101 power supply
    1.ground
    2. 5.38
    3. 5.28
    4. 13.56
    5. 13.58
    6. 51.20
    7. 51.22
    8. 36.76
    9. 37.77
    10. 36.78
    11. 28.13
    12.ground
    13. -13.32
    14. 51.31
    15. 18.41
    16.ground
    17. -46.6
    18. -46.65

    I am amazed at how many capacitors were out of tolerance. I only came across 1 cracked solder joint, after reading posts and watching videos I expected a lot more.
     
    Last edited: Mar 23, 2018

     

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  2. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    Well it was going pretty good today, I found a bad solder joint (mine) on the protection board. I put the new tranistors on the protection board AWM-062 and it was working again:banana:. I just finished up replacing the transistors on the power supply and turned it on and relay wouldn't kick in again. :( So I started taking measurements on all the pins of AWM-062 and AWR-101. I took measurements right up to pin 13 on the power supply and I shorted the pins with my lead.:mad: I blew 2 fuses, pin 25 and pin 26.on AWR-101 power supply.I'll have to see if I can locate the short tomorrow.There goes my Saturday!!! lol
     
  3. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    I found a couple of transistors that went bad Q2 and Q4 a result from shorting the leads with my dimm.I replaced them and fuses.Q2 was completely shorted.
    I have no voltage to the base of Q5. I believe its R7 Resistor because I have no power to the base on Q5. All this because of a short. If nothing else its helping me with my troubleshooting skills. Thank God there's a good service manual for this receiver or I would be SOL.
     
  4. spark1

    spark1 Super Member

    Messages:
    1,213
    Location:
    The Great Midwest
    If you are using standard probes, put friction tape around all but the very tip to minimize chance of shorting. Mini-clip probes can be very helpful as well. Good luck with your project.

    EDIT: Just curious...regarding all the out of spec caps; do you mean slightly off (less than 10-20%), or way off (>20%). Thanks.
     
  5. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    I would say most of them were around the 20% out of spec. I had to that were way more than 20%
    I was right about the resistor. I unsoldered it from the board and flipped it over and half of it was missing. Blew my mind.
    HAHA... Remember that old game operation? Thats what I think of when I'm probing around now.
     
  6. spark1

    spark1 Super Member

    Messages:
    1,213
    Location:
    The Great Midwest
    Many of the caps used in production of your receiver, and still today, have specified tolerances of 20%.
     

     

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  7. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    I went back and checked the values on the bad caps.
    6 were OL
    8 were 50+% off
    12 were 20- 50%
    4 were boarder line or good with high esr.
     
  8. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    I've tried to find a ESR chart for testing capacitors, they all seem to differ from one to another.
    I have the DER EE DE-500 and have it set to 100 hz. Is there a specific chart I should follow?
     
  9. tarior

    tarior Dirty pool, old man? Subscriber

    Messages:
    6,503
    Location:
    Kelso, Washington
    Capacitance tests in circuit aren't valid. Too much interaction with other components.
     
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  10. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    I agree with you tarior. I've done tests on that in the past. I would test a capacitor while in circuit and then remove it from the circuit to test again out of circuit and compare the values. The results were surprisingly close but I believe your circuitry definitely has an impact on readings.

    Oh and all the capacitors I was referring to above were all out of circuit tests.
     
  11. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    Well the power supply is kicking my butt. I searched and pulled components to check values and I cant find whats wrong. I sure could use someone just to narrow it down a little.
    I took some new pin measurements.

    Power supply AWR-101

    1.ground

    2. 5.22

    3. 5.16

    4. 13.44

    5. 13.47

    6. 50.71

    7. 50.74

    8. 36.61

    9. 36.62

    10. 36.64

    11. 28.28

    12.ground

    13. -.01

    14. -3.42

    15. .27

    16. ground

    17. -46.33

    18. -46.35

    19. -.01

    20. 0

    21. 0

    22. 7.76 AC

    23. 7.77 AC

    24. 0

    25. -.17

    26. -.17

    27. -.12

    28. -.14

    protection board AWM-062

    1..3-.9 fluctuates

    2. -.01

    3. .3-.6 fluctuates

    4. 0

    5. .3-.8 fluctuates

    6. .3-.8 fluctuates

    7. .4-.7 fluctuates

    8. .4-1 fluctuates

    9. 36.72

    10. 36.72

    11. 36.73

    12. AC 7.97

    I'm sorry if I'm a pain in the butt, but I sure could use a little help.:dunno:
     
    Last edited: Mar 29, 2018

     

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  12. 1MEGΩ

    1MEGΩ Active Member

    Messages:
    184
    Location:
    Mamou, Louisiana
     
    Last edited: Mar 29, 2018
    nackesww likes this.
  13. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    Thanks 1MEGO. :) I went back and changed it.

    This is going to help me a lot!!

    I'm new at this and I'm learning so much in such a short time. What is confusing for me right now is figuring out how to follow the flow of the electricity through circuits. The positive rail goes from + to-. How does a negative rail flow? I would guess + to -.

    For troubleshooting purposes does any other boards affect the pin measurements On the power supply?
     
    Last edited: Mar 29, 2018
  14. 1MEGΩ

    1MEGΩ Active Member

    Messages:
    184
    Location:
    Mamou, Louisiana
    Please re read my reply, as I edited it.
     
  15. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    I checked the fuses and there all fine. However On pin 24 I'm getting continuity across the fuse terminals with no fuse in place.
     
  16. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    On Q7 I have C-0,B-0, E-.28
     

     

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  17. 1MEGΩ

    1MEGΩ Active Member

    Messages:
    184
    Location:
    Mamou, Louisiana
    Pin 24 has nothing to do with pins 13, 14, and 15. I need to know what the DC voltage is at pins 13, 14 and 15.
     
  18. 1MEGΩ

    1MEGΩ Active Member

    Messages:
    184
    Location:
    Mamou, Louisiana
    Ok, what is the voltage at pin 6?
     
  19. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    pin 6 is 0
     
  20. nackesww

    nackesww Member

    Messages:
    96
    Location:
    New Auburn, Wisconsin
    13. 0
    14. 0
    15. .23
     

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