Pioneer Spec 2 Issue

Discussion in 'Pioneer Audio' started by xXColdShotXx, Dec 30, 2018.

  1. rcs16

    rcs16 AK Subscriber Subscriber

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    if you are measuring it in ckt, it could be the other components connected to it, making it seem that way, check/remove it out of circuit, if you have not already done so.
     

     

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  2. xXColdShotXx

    xXColdShotXx Active Member

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    It was out of socket when it gave the result. I tested all the old transistors from q4, q5, q6, q7, q12 and q13 and it was the only one that test as a resistor. This is what I test the components with.
     
  3. xXColdShotXx

    xXColdShotXx Active Member

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    I changed all the transistor on right AWH-045 board and did a DBT test, now it comes out of protection mode and the right meter doesn't go almost wide open. Would I still need to adjust VR1, VR2 and VR3 since I only changed transistors?

    Right AWH-045 VR1 has 0mv. Left AWH-045 VR1 has around 30mv.
     
    Last edited: Jan 2, 2019
  4. zebulon1

    zebulon1 Building a new bench. Finally! Subscriber

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    You need to follow the service manual and check/set the amp settings.
    The limiters, if not messed with, should be fine and can be set later when you have access to some required equipment.
    The DC Balance can be set on the DBT. The Idles can be checked for adjustment on the DBT then cranked back to a minimal setting before full power is applied. Once on full power set them to the manual.
     
  5. xXColdShotXx

    xXColdShotXx Active Member

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    I get 0mv reading on right AWH-045 board VR1. I get close to 30mv reading on left AWH-045 board VR1.
     
  6. xXColdShotXx

    xXColdShotXx Active Member

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    I got the 2 caps on AWR-093 power supply board changed. Still have to change the relays, may wait till some other time to do them. They both look decent from what I can tell.
     
    Last edited: Jan 3, 2019

     

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  7. xXColdShotXx

    xXColdShotXx Active Member

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    Finally able to get a reading on the right AWH-045 VR1, I get around 16.1mv. The left side is the same as before at around 28-30mv.
     
  8. zebulon1

    zebulon1 Building a new bench. Finally! Subscriber

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    If your describing the DC Balance? Those readings are pretty good for a nonadjustable balance.
    I forgot the Balance is set on those amps. :confused:
     
  9. xXColdShotXx

    xXColdShotXx Active Member

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    The right side AWH-045 VR1 is turned wide open and it is getting 16.5mv. Tested the speaker terminals, left was showing -27mv and right was showing -4.5mv.
     
  10. xXColdShotXx

    xXColdShotXx Active Member

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    I am getting a 8.5mΩ reading from the new reed relay outer pins? I get around 2.2kΩ on the 2 inner pins.

    Update: I took one of the out wires off and tested and got OL reading on DMM Ω setting.
     

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    Last edited: Jan 3, 2019
  11. zebulon1

    zebulon1 Building a new bench. Finally! Subscriber

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    The speaker terminals will show the DC Balance if the Protection relay is engaged. The Spec amps do not have a Balance adjustment.
    Only an Idle adjustment.
    The Idle procedure is hard to discern. You have to use the illustration on the same manual page as the description. Don't worry about the reed relay.
    So you rebuilt the amps and already began check/setting the adjustments?
     

     

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  12. xXColdShotXx

    xXColdShotXx Active Member

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    I rebuilt one AWH-045 (Right) board, but hate to do the other side without getting the rebuilt one VR1 lined out. I have been inspecting all the components I put in and they all seem to be in the correct way. I'm not sure why the idle current is so low with the VR1 turned to max.
     
  13. xXColdShotXx

    xXColdShotXx Active Member

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    What's the best way to test NEC 2SD555's and 2SB600's?
     
  14. xXColdShotXx

    xXColdShotXx Active Member

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    Anyone know the digikey or mouser part # for the green quick disconnect strips with screws I see people put of some PCB's? I may have to get some to keep from have to take the output transistors in and out so much. Are there any for the Spec 2?

    Like those in the attached pic.
     

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    Last edited: Jan 3, 2019
  15. zebulon1

    zebulon1 Building a new bench. Finally! Subscriber

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    Double check your solder connections.
     
  16. xXColdShotXx

    xXColdShotXx Active Member

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    I am gonna have to scrape some of the coating off the copper traces and make sure all the components I put in are connected good. Someone has worked on it before and burnt the copper pads off some of the board. I ordered some terminal barrier blocks for the output transistor wires, just hope they'll fit.
     

     

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  17. zebulon1

    zebulon1 Building a new bench. Finally! Subscriber

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    I use the cutoffs from the larger board caps. Connect with the two points. Clean the trace with a Scotch pad, flux and then solder. I might run the splice to the next closest component leg on the trace. Bend a small loop in the end(s) and conform the cutoff to the trace. If you take your time, it turns out pretty good looking.

    The solder pads will lift and tear from the trace very easily. The chances are higher if using the solder wick. It's happened to me on those Spec boards using the Hakko desoldering tool.

    Check for broken traces with your meter (In ohms). It only takes a few minutes. Checking end to end of the trace and each component leg between it.
     
    Last edited: Jan 3, 2019
  18. xXColdShotXx

    xXColdShotXx Active Member

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    I have a desoldering machine that sucks the melted solder off. It has done a good job so far. I went through the board again and tried to fix spots that looked not so good.
     
  19. xXColdShotXx

    xXColdShotXx Active Member

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    After/if I get this project finished I'm going to get the SX-1250 EQ and tone boards done.
     
  20. rcs16

    rcs16 AK Subscriber Subscriber

    Messages:
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    Location:
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    Anyone know the digikey or mouser part # for the green quick disconnect strips with screws I see people put of some PCB's? I may have to get some to keep from have to take the output transistors in and out so much. Are there any for the Spec 2?
    You have to versify pin spacings to see if these will work. These are 7,5mm spacings and come in 2 & 3 pin version that gang together to make larger.
    T/E(AMP) models 282844-2, 282844-3
    Both are available at Mouser or Digi-key
     

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