REVOX B225 TROUBLE READING DISC

[isitrisky]

My Revox B225 has intermittent trouble reading disc's. Once a disc has stopped playing, and I go to insert a new disc it wont play it. Disc spins for a second or 2, and stops. I have to open and close tray a few times to get it to play. Once it starts to play, it will play that same disc a thousand times as long as i dont open and close the tray. There are a few moments where the opening/closing has no bearing on whether it plays or not. Not sure what it might be. rails are clean. tray closes firmly. Any help would be appreciated.

[poynton]

It sounds to me like the disk is not always sitting at the correct height relative to the laser.

Even though you say the rails etc. are clean, the first thing I would do is to strip down the mechanism and give it a thorough clean.

If you have a manual, there is a procedure for checking / setting the laser height.

Whatever you do, do not be tempted to adjust the laser controls.
The laser is working fine as they are!



.

[kevinkr]

Fixed thread title

[isitrisky]

Originally Posted by poynton

It sounds to me like the disk is not always sitting at the correct height relative to the laser.

Even though you say the rails etc. are clean, the first thing I would do is to strip down the mechanism and give it a thorough clean.

If you have a manual, there is a procedure for checking / setting the laser height.

Whatever you do, do not be tempted to adjust the laser controls.
The laser is working fine as they are!



.

I aint touching the laser...i'm more concerned that it might be one of those blue ribbons having a kink somewhere?

[PlasticIsGood]

Could be the tray isn't always dropping far enough to clear the edge of the disk.

If you get it working and switch off for a few minutes with the disk loaded, does it still play when restarted?

If the loader's got plastic rollers running in steel or alloy cam slots, then lubrication after cleaning is problematic. They are beginning to crack and crumble with age, and misguided greasing has in some cases hastened the process. I've used a 100% synthetic oil on the axles only but I'm still a bit worried. If your loader is clean and working and not greased, then I would leave it as it is.

There may be an adjuster for the mechanism that drops the tray.

I wouldn't adjust the spindle height until sure that the disk is seating properly and spinning freely.

Which mech is it?

[stephensank]

The B225 uses the CDM-0 mechanism, and your your symtpom is a totally classic indication of platter motor bearing wear, which is easy to compensate for. If you remove the bottom "hatch" from under the mech, just take a #T10 Torx driver & turn the ferrite center insert you'll see practically dead center of the mech, middle bottom of the platter motor. Use the Torx driver to turn the insert clockwise, a little bit at a time, until a number of cd's have no trouble playing. You should not have to do more than 3/4 to 1 turn.

Once you have it in a spot that reliably plays every cd you try, use a bit of Duco cement or etc. along the edge of the threaded insert to lock it into place.

[isitrisky]

Originally Posted by PlasticIsGood

Could be the tray isn't always dropping far enough to clear the edge of the disk.

If you get it working and switch off for a few minutes with the disk loaded, does it still play when restarted?

If the loader's got plastic rollers running in steel or alloy cam slots, then lubrication after cleaning is problematic. They are beginning to crack and crumble with age, and misguided greasing has in some cases hastened the process. I've used a 100% synthetic oil on the axles only but I'm still a bit worried. If your loader is clean and working and not greased, then I would leave it as it is.

There may be an adjuster for the mechanism that drops the tray.

I wouldn't adjust the spindle height until sure that the disk is seating properly and spinning freely.

Which mech is it?

CDM-0...and yes once I get it working, if I turn it off, and back on in a day it works, its only when i open it does it go out..after a few open/close sessions it works again.

[PlasticIsGood]

Originally Posted by isitrisky

CDM-0...and yes once I get it working, if I turn it off, and back on in a day it works, its only when i open it does it go out..after a few open/close sessions it works again.

Good. That should eliminate confusion with temperature-related problems.

If you are satisfied that the disk is seating properly and spinning freely, then checking the spindle height will probably reveal the problem. It is better to do this as per the manual, because the procedure will eliminate other possible causes before you disturb the current setting. It also should allow you to set the height so the focus motor is in the middle of its range for a flat disk playing a middle track. Then the mech will be most tolerant.

Someone with experience of your servo board might be able to tell you where the test point is. Basically you measure a voltage on the servo board that reflects the focus motor position, and adjust the screw under the spindle until the voltage is within a range specified in the manual. If it already measures correctly, then that would cast doubt on the diagnosis.

I wonder, if you can't measure and have to use trial and error instead, would it be best to use a reasonably warped disk?

With CDM1 mechs needing adjustment I remove the spindle bearing, clean it and the bottom of the spindle, and reassemble with a spot of synthetic oil on the top of the screw. Perhaps this is also possible on the CDM0 without disturbing any other settings.


The other possibility is a poor electrical connection affected by movement during loading.