Hello everyone,
I’m encountering an issue with my Pioneer PD-91 CD player. When it is flat, the disc doesn’t spin when I press "play," only a slight movement is visible. However, as soon as I place the player on its side (about a 45° angle), the disc starts spinning normally and playback works perfectly. Once the disc has started, I can place the player flat again, and it continues to work perfectly without any issues 😕.
I’ve cleaned the lens, but the problem persists. Could this indicate that the PWY 1004 laser is dead, or could it be another issue (spindle motor, alignment, clamp mechanism, etc.)?
I would love to hear if anyone has experienced a similar problem and if you have suggestions on any adjustments I could make to improve the situation. Are there any settings or simple repairs I could try before concluding that the laser is faulty?
Thank you in advance for any advice and feedback!
I’m encountering an issue with my Pioneer PD-91 CD player. When it is flat, the disc doesn’t spin when I press "play," only a slight movement is visible. However, as soon as I place the player on its side (about a 45° angle), the disc starts spinning normally and playback works perfectly. Once the disc has started, I can place the player flat again, and it continues to work perfectly without any issues 😕.
I’ve cleaned the lens, but the problem persists. Could this indicate that the PWY 1004 laser is dead, or could it be another issue (spindle motor, alignment, clamp mechanism, etc.)?
I would love to hear if anyone has experienced a similar problem and if you have suggestions on any adjustments I could make to improve the situation. Are there any settings or simple repairs I could try before concluding that the laser is faulty?
Thank you in advance for any advice and feedback!
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Check all the Alignments.
The Focus Offset could be out.
Worth checking the Mechanical alignments of the Laser, the beautiful thing with Pioneer Lasers of this age is that everything is align-able.
The results should tell you if the Laser is worn. The age of the Player may mean that it is :-(
P.
The Focus Offset could be out.
Worth checking the Mechanical alignments of the Laser, the beautiful thing with Pioneer Lasers of this age is that everything is align-able.
The results should tell you if the Laser is worn. The age of the Player may mean that it is :-(
P.
They are known for the laser lens to become unglued. Reglue and let set if it has. The other big one is a bad spindle motor, but table height is critical.
DO NOT ADJUST ANYTHING !!!!!!! It once worked adjusted as it is. Do not mess with it.
DO NOT ADJUST ANYTHING !!!!!!! It once worked adjusted as it is. Do not mess with it.
I have seen loose ones. The ones upside down generally dropped due to being run over a hotter component. If you were lucky the lens was stuck in the grease somewhere. Clean and glue it back in normally saved the head.
I have not seen many heads where the laser was bad. My memory is foggy, but if the laser current is marked on the head or cable, measure the Iop. You're allowed 10% increase - then it is at end of life.
Just check the disc table is clean. I would be looking at the RF pattern first if you got it running. Only then would adjustments be attempted. So you need a good oscilloscope that will show a clear eye pattern, 0.5 uS/div and about 0.5V/div vertical. If you don't have this instrument, then just stop. You are completely unable to do anything without a good oscilloscope. Note most digital scopes do not show a clear eye pattern.
I have not seen many heads where the laser was bad. My memory is foggy, but if the laser current is marked on the head or cable, measure the Iop. You're allowed 10% increase - then it is at end of life.
Just check the disc table is clean. I would be looking at the RF pattern first if you got it running. Only then would adjustments be attempted. So you need a good oscilloscope that will show a clear eye pattern, 0.5 uS/div and about 0.5V/div vertical. If you don't have this instrument, then just stop. You are completely unable to do anything without a good oscilloscope. Note most digital scopes do not show a clear eye pattern.
Also early Sony Mobile Audio Cd player mechs...oooofff going back in time....what ever you do to that Pioneer don't touch the 'grating adjustment' if at all possible
I have the diffraction grating adjust tools for many heads. A real pain, touchy. A technician's hell if he does a good job. Messed up a lot of CDs doing this. If the head is running - do not touch this!
I remember most heads were okay out of the box, but Pioneer heads never were. Yamaha was another.
I remember most heads were okay out of the box, but Pioneer heads never were. Yamaha was another.
Thanks for your answers !
I've followed the test mode procedures, and everything is responding correctly. The spindle motor starts perfectly even when the player is flat, so I can rule out the motor as the issue.
I've completely disassembled the player and found nothing unusual mechanically. The disc table appears to be aligned, and all the components are properly lubricated. There are no obstructions or issues with the movement.
At this point, should I proceed with more advanced tests, like adjusting the laser, or should I continue investigating the mechanical side? I’m wondering if the laser needs adjustment despite the motor and mechanical elements seeming fine.
sm : https://docs.stoneset.fr/ELECTRICAL_AUDIO/PIONEER/pd-91_sm.pdf
I've followed the test mode procedures, and everything is responding correctly. The spindle motor starts perfectly even when the player is flat, so I can rule out the motor as the issue.
I've completely disassembled the player and found nothing unusual mechanically. The disc table appears to be aligned, and all the components are properly lubricated. There are no obstructions or issues with the movement.
At this point, should I proceed with more advanced tests, like adjusting the laser, or should I continue investigating the mechanical side? I’m wondering if the laser needs adjustment despite the motor and mechanical elements seeming fine.
sm : https://docs.stoneset.fr/ELECTRICAL_AUDIO/PIONEER/pd-91_sm.pdf
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Run through the diagnostic procedure. The lens should do a focus search. DO NOT ADJUST THE LASER CURRENT !! if you do, just throw the machine out. A new laser head must be set up, the diffraction grating is out. A new head will not even read a disc. Either that or take it to a good tech who used to service them. They need the diffraction grating tool, and the experience to align them.
We have other tools, like laser power meters and equipment that allow us to check far more deeply. I've seen people who will not pay someone (for whatever reason) that destroy a machine over what was a simple fault. This goes for all equipment.
We have other tools, like laser power meters and equipment that allow us to check far more deeply. I've seen people who will not pay someone (for whatever reason) that destroy a machine over what was a simple fault. This goes for all equipment.