Hi,
Recently I was stupid enough to place my cdp in a different area, where it became a lot warmer than usual. After a month or so, it started with only reading a disc after 20-30 minutes of power on. At the end of that same week, when finally playing a disc it started skipping a lot, so it kinda became clear something serious needed to happen.
I had the player recapped and it plays cd's in good condition well now. Although the player/ laser isn't able to read cd's with some form of damage anymore. (which it had no problem at all with before)
Im looking forward to hearing what you think could cause this.
Also if it's necessary to replace the laser, is it possible to just replace the "laser" part of the Studer cdm-1? Or is it necessary to replace the entire transport, and if so, would it make a difference in sound or the functioning of the player?
Thanks a lot for your help.
Recently I was stupid enough to place my cdp in a different area, where it became a lot warmer than usual. After a month or so, it started with only reading a disc after 20-30 minutes of power on. At the end of that same week, when finally playing a disc it started skipping a lot, so it kinda became clear something serious needed to happen.
I had the player recapped and it plays cd's in good condition well now. Although the player/ laser isn't able to read cd's with some form of damage anymore. (which it had no problem at all with before)
Im looking forward to hearing what you think could cause this.
Also if it's necessary to replace the laser, is it possible to just replace the "laser" part of the Studer cdm-1? Or is it necessary to replace the entire transport, and if so, would it make a difference in sound or the functioning of the player?
Thanks a lot for your help.
CDM-1 in Studer / Revox dies because of heat from the green lamp.
Check if the spindle motor turns freely, eventually use some good oil.
Check if the spindle motor turns freely, eventually use some good oil.
Thank you for your reply.
The cdm-1 is in a Studer A727.
I will check the spindle motor. The player makes an "rrrrrrrr" sound and then stops after 2-3 seconds of doing that, resulting in not reading the disc.
Now after about an hour or so of being turned on it seems to take in a disc finally and plays it just fine.
All caps were replaced, including one under the drive mechanism.
I will see if the spindle motor is moving freely.
Any other suggestions are very welcome.
The cdm-1 is in a Studer A727.
I will check the spindle motor. The player makes an "rrrrrrrr" sound and then stops after 2-3 seconds of doing that, resulting in not reading the disc.
Now after about an hour or so of being turned on it seems to take in a disc finally and plays it just fine.
All caps were replaced, including one under the drive mechanism.
I will see if the spindle motor is moving freely.
Any other suggestions are very welcome.
The laser in the CDM-1 is very unlikely to fail. You wrote all capacitors have been replaced, including one under the drive mechanism.
Actually there are 5x 33uF/16V axial capacitors under the drive mechanism, related to the servo circuit. You need to replace all of them, they are notoriously responsible for failure of the CDM-1. Your symptom seems a servo issue.
Actually there are 5x 33uF/16V axial capacitors under the drive mechanism, related to the servo circuit. You need to replace all of them, they are notoriously responsible for failure of the CDM-1. Your symptom seems a servo issue.
Here is a picture of the studer cdm-1 I have:
An externally hosted image should be here but it was not working when we last tested it.
Does it have 5 caps?
My C.D.M.-1 Service Manual says (in Dutch):
Sticker C.D.M. - F: Zie Service Manual CDM-0
which I don't have...
Sticker C.D.M. - F: Zie Service Manual CDM-0
which I don't have...
That is a CDM-0, and I do see one horrid light blue Philips cap on the little board the laser ribbon cable is plugged into, which should be replaced.
Assuming laser current is correctly adjusted(which needs to be done on a variety of cd's for best compromise adj point, not just one test disc), the #1 most likely problem is simply platter motor thrust bearing wear. Fixing is simply a matter of turning clockwise the torx #10 head "screw", which is the bearing itself, right there with the "F" sticker next to it on the bottom of the motor. Just turn it clockwise in small increments until you get good reading of a number of cd's, or you can adj for max rf amplitude at an rf/"eye-pattern" test point with an oscilloscope.
Assuming laser current is correctly adjusted(which needs to be done on a variety of cd's for best compromise adj point, not just one test disc), the #1 most likely problem is simply platter motor thrust bearing wear. Fixing is simply a matter of turning clockwise the torx #10 head "screw", which is the bearing itself, right there with the "F" sticker next to it on the bottom of the motor. Just turn it clockwise in small increments until you get good reading of a number of cd's, or you can adj for max rf amplitude at an rf/"eye-pattern" test point with an oscilloscope.
Thanks for your reply! I already planned on trying that (adjusting spindle height and /or replacing the bearing),also thanks to members of the AK forum😉 I will keep you posted on the result.
ps: the above picture was not the actual mech I have, but one like it.
Here is mine:
ps: the above picture was not the actual mech I have, but one like it.
Here is mine:
An externally hosted image should be here but it was not working when we last tested it.
Spindle motor does not turn freely indeed. When pressing play, the disc moves a few cm and seems stuck, the motor increases power and eventually manages to get it loose and spinning, but just not fast enough.
On the top side of the transport, there is necessarily a small gap between the platter and the CDM1 chassis.
Put a drop of oil on the tip of miniature screwdriver and bring it there. Repeat until oil finds its way to the spindle shaft. Turning the spindle helps, also the platter can be pulled out very little to make the gap more big.
Put a drop of oil on the tip of miniature screwdriver and bring it there. Repeat until oil finds its way to the spindle shaft. Turning the spindle helps, also the platter can be pulled out very little to make the gap more big.
No, on the picture is CDM1 transport. The capacitor in question is metallic blue in proximity of laser current trimpot.
The spindle height adjustment is done by measuring the output voltage on focus motor amplifier. By the book, it is a bit complex because the adjustment should take into account the offset of the test CD. In practice, the offset voltage should be measured without CD and then adjusted with any CD playing track 1 to the same voltage as without CD by turning the spindle thrust bearing clockwise in small increments.
The eye pattern adjustment with oscilloscope is for adjusting radial motor offset, not the spindle height.
Skipping CDs may also be the result of misadjusted radial motor power. This is done by placing the player in the service mode and adjusting the voltage oon radial motor amplifier to 0 +/-50mV to compensate for stiff connector strip or mechanical resistance of the axis.
Last edited:
- Status
- Not open for further replies.