This high end laser disk player from 1990 plays CDs fine, but when a LD is inserted, it only spins for a few revolutions before it ejects it. My first instinct would be to say the optical pickup is bad, but other LD players I've seen with problems try a lot harder to play before giving up. I don't think it's the spindle motor because when it's playing a CD it has plenty of torque (I actually can't slow down the disc by holding the spindle). The pickup moves freely and the tilt motor is working. Since I don't have a service manual, I'd like to hear any ideas before I really dive into it. Andy Cuffe
So the spindle motor on this one is used for both LDs and CDs?
With only a few revolutions and I assume never getting up to speed, it can't even know if the LD is valid so sounds like it may be shutting down due to another problem.
There is also the newsgruop alt.video.laserdisc though they don't do much in the way of repair there.
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Yes, it uses the same motor for both which is obviously massive overkill for CD playback. Since it has lots of torque when playing a CD, I would think it could spin a LD faster than it does.
It never gets faster than about 10 RPM when loading a LD. I can see some RF at the test point (although way below its normal frequency due to the low speed), so it must be more or less focusing.
It seems strange that it gives up so fast. Other LD players will grind away for a couple of minutes when they have trouble playing a disc. It's also odd that it ejects the disc when it fails. I'm hoping someone can tell me what this model normally does when it can't play a LD.
I've already checked for obvious problems such as power supply voltages and gross mechanical problems. I'll double check for sensor problems that might be causing it to reject the disc. Andy Cuffe
It does realize it's an LD in there and not a CD, right? :)
With any RF, it's focusing. I assume you mean 10 rps. I doubt there is any way it can conclude the LD is bad at 10 rps. I assume you've tried more than one LD.
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It does correctly say LD in the display. I actually do mean 10 RPM! It's a stretch to call it RF at that speed, but there's a definite signal at the test point. I compared it to a different LD player and it spins up the disc as soon as it detects it.
It's definitely a problem with the LD spindle servo which is separate from the CD servo. There's virtually no voltage on the LD spindle error line (which is labeled on the board). I tried applying an external voltage to it through a 10 k resistor and the spindle motor immediately came up to speed (of course, not in sync). I traced the error signal back through an amplifier circuit and everything seems fine there. It then goes back to a large custom IC.
By this time, the player was working better than before. It was actually spinning the disc at almost the right speed and produced intermittent video. After allowing it to cool down it was exactly as it was before. Leaving it turned on in stop mode for about 30 minutes is enough to get it to start partially working again.
Clearly there's a thermal problem. Hopefully just an electrolytic somewhere. A couple of times it has suddenly turned itself off without warning (as if I had pulled the plug). I'm going to pull the power supply and also check the various regulator circuits scattered around the other boards. Fortunately, unlike most Pioneer LD players, most of the boards are accessible while the player is assembled. Andy Cuffe
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How much voltage? I have the exact same problem on a CLD95. 0 voltage and no signal on the error line but when I applied 2 volts to the error line the spindle motor starts to spin up for a few seconds.
I found a beat up, but working low end model with the same transport. To cut a long story short, it was the pickup. Swapping the pickup from the parts machine into the CLD-92 got it working. It didn't even need any alignment.
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