Sony CDP-C335 carousel doesn't align with clamping assembly.

You know, I rather think I have, but I can't for the life of me remember what was causing it. Was it a mechanical alignment issue maybe ? I have a dim recollection of something geared being a tooth out. A further dim recollection is of letting it settle in the jammed position, then de-powering and undoing the screw in the centre of the carousel, and lifting it to disengage it from its drive so that it could be rotated to line up correctly, before dropping it down again, and refitting the screw. I might be thinking of something else entirely, but something is chiming deep in the shadowy recesses of what passes for my mind ... :-)

Arfa

From what I can tell, there are some optical sensors that monitor the position of the carousel. So removing the carousel and then repositioning it shouldn't really matter. When I removed the carousel to inspect the belt, I reinstalled it so it was centered. I'm wondering since it's always hitting the trailing edge of the hole, perhaps the carousel isn't braking soon enough after the uP turns off the carousel motor?

Thanks for your reply.

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David Farber 
Los Osos, CA

I think I would look at the flat wire from the carousel down to the main board. Seen a few bad, and the opto-sensing would certainly be affected by this.

Mark Z.

Hi Mark,

The flat wire checks ok. I've looked around this area and the only suspicious thing I've found is that the carousel has a lot of loose travel in it when it's at rest. I measured about 2.5mm of wiggle room at the circumference of the carousel. That's plenty of error to cause problems. I think the intermediate gear between the worm gear and the carousel is worn out. It's location #66 on the parts blowup on page 22 of the service manual here: http://www.electronica.ro/service_manuals/sony/compact_disk_player/cdp-c335/

Thanks for your reply.

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David Farber 
Los Osos, CA

This problem is usually 1 of 2 things.

1) The gears are outof timing by 1 tooth. 2) The green flat cable that goes fro the deck to the board is defective. This won't be visible as the connections are intermittant. Replace the cable first. This may resolve the problem.

Dan

Hi Dan,

The position of the carousel is controlled by the photo transistors. When the slits underneath the carousel line up in whatever formation the uP is looking for, the carousel motor stops turning. When the unit is powered up from an unplugged condition, the carousel spins and orients itself so that disk 1 is facing the user. In that respect, it doesn't matter what position the carousel is in when the unit is powered up, it can figure out where each disk is and how far to spin the carousel. I don't understand how a defective cable could cause the carousel to be misaligned by a couple of millimeters. Don't you think it would totally lose track of its position if the cable were bad?

So taking that all into consideration, I took some needle nose pliers and slightly tweaked the metal pin that was misaligned with the hole in the carousel. Now it fits just fine when the cam elevates the play mechanism into position.

Thanks for your reply.

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David Farber 
Los Osos, CA

The cable I described developes cracks with age. This causes intermittant connections withint hte cable. I have repaired a number of these units, som e of which had the problem you described. Some of these also were "fixed" by replacing the cable. The cable is by no means the only cause of hte pro blem you describe. The photo trnasistors can be bad, the digital transisto rs (DTC) that "digitize" the transition can be faulty as well. The bottom line here is that there are many potential causes of the problem. Experien ce will provide you with clues (as I and others posted here).

A cam gear off by 1 tooth can cause this problem as well. Obtain the servi ce manual which contains the alignment marks to verify proper alignment of the tray as well.

Dan

I say -- without sarcasm -- that it's gratifying when common sense works. (It so rarely does when servicing electronic equipment.)

The reason this wasn't solved sooner was that there was no obvious /reason/ why the pin should have been misaligned in the first place. How /could/ it have gotten misaligned?

I had a similar problem 40 years ago. I pulled out my Nikon F and discovered the film advance was jammed. It turned out the take-up hub had been BENT at the middle, as if someone had banged it with a mallet. How did it happen? I never learned.

Hi Dan,

I'll recheck the timing again. Though I don't understand what the timing of the cam that closes and opens the drawer and raises and lowers the play mechanism has to do with the positioning of the carousel. I've worked on enough of these carousel players to know that when the timing is off by one tooth in one direction, the drawer closes all the way while the cam is still continuing to try and push it even further. As a result, the cam gets jammed and that's the end of that loading cycle. If it's off by one tooth in the other direction, the clamping assembly will bite down on the disk before it's pushed all the way to the back of the mechanism. Neither of these faults has anything to do with the rotation of the carousel as far as I can tell. Also, I'll try and find a way to put a scope probe on the photo transistors and see if there's a clean signal coming off of there.

Thanks for your reply.

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David Farber 
Los Osos, CA

The pin probably wasn't misaligned in the CD player. Anywhere along the line there could have been something that was warped. But the easiest way to correct it was to just tweak the pin.

By the way, that Nikon F is a sweet camera. (-:

Thanks for your reply.

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David Farber 
Los Osos, CA