Troubled PDR-04

Discussion in 'Pioneer Audio' started by thefragger, Sep 12, 2011.

  1. thefragger

    thefragger Certified Crazy.

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    Hi, All!

    I picked up this CDP/R, only to find that it won't open when I press the eject button! Also, when I turn the player 'off,' the standby light flashes.

    Anyone in here ever seen this problem before or know of a way to manually eject the tray? I don't see any screwdriver slots or pin-press areas underneath (and I do understand that this is the more complex Stable Platter mechanism as opposed to a standard tray).


    :scratch2:
     
  2. thefragger

    thefragger Certified Crazy.

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    Update:

    I found a linkage under the transport assembly that, when manipulated, lifts the assembly and ejects the drawer. (awesome!)

    So then I plugged it in, and pressed the eject button. The drawer started to close so I pressed the button again quickly and the drawer stopped dead while the display read 'open.' I pressed the button again and the drawer continued to close, and even after it was closed the motor continually ran.

    Time to figure out where the limit switches connect, or I might have to dig 'em out...
     
  3. thefragger

    thefragger Certified Crazy.

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    It's really very difficult to get the transport out without undoing a lot of more of the machine than I thought... limit switch tests fine.

    Hmm...
     
  4. thefragger

    thefragger Certified Crazy.

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    The limit switch and tray motor go to the same 5-pin header (two for motor, three for the switch). I unplug that header, and when I turn the player 'off,' the standby blinks two~five times and goes off.

    With the header plugged back it, it will not go into standby.


    :scratch2:
     
  5. thefragger

    thefragger Certified Crazy.

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  6. uxwbill

    uxwbill Lurking in the Shadows

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    Since you're totally stuck, my best guess is a partially shorted tray motor. It's probably hitting a bad spot and overwhelming the motor driver that is supposed to operate it, which could be causing enough of a voltage sag to screw up other operations in the unit (hence the reason why it won't go into standby).

    Couple of ways to fix it...

    1. Get a new motor. Probably easier/cheaper than you think.
    2. Try to clear the short...a shot of degreaser through any holes in the motor casing might do it, as will a sufficiently stout power supply that doesn't mind having its output shorted. (Definitely don't have the motor connected when you do this.) Crud builds up on the brushes in these little motors and it seems like Pioneer equipment has a real predisposition to this problem.
     
  7. thefragger

    thefragger Certified Crazy.

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    Interesting! I'll give 'er a try, thanks!
     
  8. Dr Tinear

    Dr Tinear AK Subscriber Subscriber

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    The problem could be on the servo control board. The PDR-04 and PDR-05 used an Elna supercap as a backup power source to keep setup parameters from getting lost if the AC power was interrupted. This cap has the unpleasant tendency to puke corrosive electrolyte on the board when it fails. When the electrolyte eats through the traces, you end up with all sorts of interesting symptoms. Reworking the board requires steady hands, good eyes and a great deal of patience. I gave my PDR-04 and PDR-05 to a technician friend to use as parts donors because I didn't have the time or inclination to do that messy repair on either one of them.
     
  9. thefragger

    thefragger Certified Crazy.

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    I did note the supercap, I didn't see any leakage. This is what mine looks like:

    [​IMG]
     
  10. dr*audio

    dr*audio Fish fingers and custard! Subscriber

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    Look at the board under the cap very carefully for any sign of contamination. Look on the bottom side, too. On the one I worked on, the electrolyte wasn't so apparent on the top, but oozed through the feed thru holes to the bottom. If the cap is ok, see if there is a belt that drives the drawer and is slipping. If you do get it fixed, change the super cap before it fails.
     
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  11. Cosmin2000

    Cosmin2000 Active Member

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    I have the same problem with my PDR-05, the drawer does not open anymore. Is this the supercap that you are pointing, dr*audio?
    Because I cannot read due to other parts in the way, anyone knows the specifications of this cap (capacity, voltage)?
     

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  12. dr*audio

    dr*audio Fish fingers and custard! Subscriber

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    The super cap is the one standing on it's side toward the rear and is has leaked all over the board.
     
  13. Cosmin2000

    Cosmin2000 Active Member

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    Thanks, dr*audio! I found from the service manual of the PDR-04 that the supercap is 0.22F/5.5V. Maybe, on my PDR-05 is the same supercap.
     
  14. dr*audio

    dr*audio Fish fingers and custard! Subscriber

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    The exact value is not critical, just the voltage rating. Be sure to clean the board with alcohol and look for damaged traces and feed thrus.
     

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