Pioneer cd player pots
- Thread starter PIY
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Hi Junie,
Have you checked that the switches are working properly? You want to check contact resistance. Don't assume anything, just check these things.
There is a service program in the service manual for most Pioneer CD players. Run that and it will tell you which system is failing. It overrides normal play operation and allows you to turn on each function in turn so you can check each signal test point. Some other makes (Denon for example) also have a "heat run" mode used for finding intermittents. It runs in a loop until it detects a failure and stores the failure code on the display. The service program will be your best friend right about now.
You will need access to an oscilloscope. Analog or a very expensive digital 'scope needed here. You will be observing both static levels, low frequency test points and the high frequency HF (or RF) and clock test points.
-Chris
Have you checked that the switches are working properly? You want to check contact resistance. Don't assume anything, just check these things.
There is a service program in the service manual for most Pioneer CD players. Run that and it will tell you which system is failing. It overrides normal play operation and allows you to turn on each function in turn so you can check each signal test point. Some other makes (Denon for example) also have a "heat run" mode used for finding intermittents. It runs in a loop until it detects a failure and stores the failure code on the display. The service program will be your best friend right about now.
You will need access to an oscilloscope. Analog or a very expensive digital 'scope needed here. You will be observing both static levels, low frequency test points and the high frequency HF (or RF) and clock test points.
-Chris
I'm not familiar with the player, but I see you mentioned at the start that 'all functions are working'. If it responds to draw open/close etc then that's a good sign.
Make sure you are following the exact procedure to get it into service mode. Sometimes its not as easy as it sounds. Make sure you follow any instructions over applying power and holding down buttons etc.
As Chris says, you do need a scope to check anything beyond the basics.
Make sure you are following the exact procedure to get it into service mode. Sometimes its not as easy as it sounds. Make sure you follow any instructions over applying power and holding down buttons etc.
As Chris says, you do need a scope to check anything beyond the basics.
I thought you meant it wasn't going into test mode at all 🙂 You would only see the RF (eye pattern) when a disc was spinning.
I've no magic fix for this I'm afraid. If I had this on the bench I would now start to go around every pin of the IC's with both a scope and a DVM and try and ascertain whether anything stood out as being amiss.
The fact it performs a focus search routine really suggests its all basically operational and so the service mode not doing what it should is a mystery. I wouldn't like to comment on that without actually having one in front of me to play around with though.
I've no magic fix for this I'm afraid. If I had this on the bench I would now start to go around every pin of the IC's with both a scope and a DVM and try and ascertain whether anything stood out as being amiss.
The fact it performs a focus search routine really suggests its all basically operational and so the service mode not doing what it should is a mystery. I wouldn't like to comment on that without actually having one in front of me to play around with though.
I know this is a really stupid question and feel free to ignore it. Did you place the disc with the read side up? As the laser reads from the top with this player.
I checked all suppy voltages going to several IC's, all are present and correct. I repair many CD player but this one I'm stuck. Now I will do trial and error by replacing the decoder IC and see what will happen. Will report back in a week or two, IC will be coming from US seller 🙂
Your Pictures show the Display looking different to normal in Test Mode so my guess is it is accessing Test Mode OK.
Can the Sled be moved back and forth with the Scan Fwd/Back keys?
The 'Programme' key turns the Focus Servo ON. (The Laser will Light and the Focus Coils should be Driven and the Lens appear to rise and fall. If a Disc is in place, and moved by hand, you should be able to 'hear' the servo at work.)
Pressing Play at the above point will engage the Spindle Servo and the Disc should start to spin. If the RF signal (Eye Pattern) is observed it should look a little 'blurred'.
Pressing Pause next will turn on the Tracking Servo which should make the Eye Patter nice and clear.
To be honest with a player of this age it's going to be the Laser.
You say it doesn't spin so you won't have any Eye Pattern but what do you observe on the 'scope at the RF Test Point when the Focus Servo engages?
P.
Can the Sled be moved back and forth with the Scan Fwd/Back keys?
The 'Programme' key turns the Focus Servo ON. (The Laser will Light and the Focus Coils should be Driven and the Lens appear to rise and fall. If a Disc is in place, and moved by hand, you should be able to 'hear' the servo at work.)
Pressing Play at the above point will engage the Spindle Servo and the Disc should start to spin. If the RF signal (Eye Pattern) is observed it should look a little 'blurred'.
Pressing Pause next will turn on the Tracking Servo which should make the Eye Patter nice and clear.
To be honest with a player of this age it's going to be the Laser.
You say it doesn't spin so you won't have any Eye Pattern but what do you observe on the 'scope at the RF Test Point when the Focus Servo engages?
P.
Hi Percy,
Yes the unit will go to TEST mode but those keys wont' response in Test mode. I called the Pioneer Service Center and had a friendly chat with the technician was advice that Optical lens is not an issue since the unit will not got to TOC, he says something wrong with the System control.
RB,
Junie
Yes the unit will go to TEST mode but those keys wont' response in Test mode. I called the Pioneer Service Center and had a friendly chat with the technician was advice that Optical lens is not an issue since the unit will not got to TOC, he says something wrong with the System control.
RB,
Junie
Does the Tray open and close?
If it does, with the Tray open, can the Play button be used to close it?
I'm racking my brains to remember changing a Main Micro in a Pioneer CD Player and I can't. I'm not saying it isn't faulty but it'd be very rare if it is.
P.
If it does, with the Tray open, can the Play button be used to close it?
I'm racking my brains to remember changing a Main Micro in a Pioneer CD Player and I can't. I'm not saying it isn't faulty but it'd be very rare if it is.
P.
I made a discovery and I have to blame my Stupidity
The TEST MODE is working, I need to remove the short pin after plugging the AC cord duh!😀
OK so the Spindle motor is working, FF/RW will track the Optical assy and Program will initiate the PLAY mode. So maybe it's an optical assy issue?
The TEST MODE is working, I need to remove the short pin after plugging the AC cord duh!😀
OK so the Spindle motor is working, FF/RW will track the Optical assy and Program will initiate the PLAY mode. So maybe it's an optical assy issue?
So talk us through what actually happens.
You press PROGRAM, then PLAY, then PAUSE and........................?
P.
You press PROGRAM, then PLAY, then PAUSE and........................?
P.
In Test mode:
I press the PROGRAM the LENS starting to light up.
Pressing PLAY will rotate the Spindle motor but I need to stop for sometimes as it whirling like a helicopter.
Pressing the PUASE will display the PAUSE sign but won't show any track number.
STOP will stop the spindle from rotating.
I press the PROGRAM the LENS starting to light up.
Pressing PLAY will rotate the Spindle motor but I need to stop for sometimes as it whirling like a helicopter.
Pressing the PUASE will display the PAUSE sign but won't show any track number.
STOP will stop the spindle from rotating.
Have you an Oscilloscope? Can you look at the RF Test Point?
With a disc loaded, when you press PROGRAM do you see any signal?
I suspect you won't, or it will be very small, too small for the player to recognise, hence no play.
Not normally recommended but a small and I mean small turn of the Laser Power potentiomemter on the Laser itself may spark things into life. I'm afraid I can't remember which direction is 'Up' so make a note of where the potentiomemter is before you start and try it both ways.
I do suspect the Laser is at fault.
P.
With a disc loaded, when you press PROGRAM do you see any signal?
I suspect you won't, or it will be very small, too small for the player to recognise, hence no play.
Not normally recommended but a small and I mean small turn of the Laser Power potentiomemter on the Laser itself may spark things into life. I'm afraid I can't remember which direction is 'Up' so make a note of where the potentiomemter is before you start and try it both ways.
I do suspect the Laser is at fault.
P.
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