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Studer Philips CDM 1 dead???

Cielo976

Cielo976

New Member
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.

UPDATED:
I had the player recapped and it still has the same problem of playing discs only after being turned on for 30-60 minutes now (due to colder temperatures outside). (observation after testing it myself)

So Im kinda wondering now if the laser has had it's best time... or if it's something else.. ?? (especially since lot's of people claim that these lasers almost never fail)
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.
 
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Hi,
Look under the laser unit and you will see the "notorius" 3x33uf blue philips capacitors. Replace them with new good quility and you are good to go!
 
Cielo976 said:
Anyone know for sure if this is the end of the laser?
Click to expand...

Please, read this: http://www.lampizator.eu/LAMPIZATOR/TRANSPORT/laser/Laserology.html

Topics include:

The top ten reasons why CD's are not read - according to "my vast experience" in that matter - are:
CD laser diagnostics - a quick guide
Is CD laser really dead ?
True indication of a dead laser circuit (not necessarily the laser itself)
Electrical circuits of the CD reading process:
CD laser transplants
 
As suggested a few times above, it is very, very rare for those Philips optical units to fail. The fact that problems are linked to time and temperature also points away from the optical unit as being the fault.

Wear of the spindle height adjustment screw is also a common reason the CDM1 becomes picky with discs.

Have youdone the obvious - cleaned the lens? (properly, NOT with one of those stupid cleaning discs)
 
Thank you for the tips!
The problem seems to be more temperature related, due to colder temperatures outside, it took a little longer for the machine to "warm up", and it plays most discs fine now after let's say 60 minutes of being turned on. It still has problems with 1 cd I often use to test a cdp on it's laser quality. CDP's with a laser that was less than good, seemed to have trouble playing this disc.
Not sure if this could also be caused by something on a pcb underneath the drive, or if it's laser related, or possibly both.
(I remember having a similar problem with a Sony Kss-272a once, where it only started reading discs after being turned on for a while, and recapping everything on the pcb underneath the drive solved it there)

The player has a lot of new caps, also 1 was replaced underneath the drive mechanism(not sure if there are more that can be replaced there) , power source was ok too) Can post pictures if that would be helpful.

Thanks a lot!
 
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That can be symptomatic of aging spindle motors. They work fine when warm, but can't get up to correct rotational speed fast enough to meet the tracking requirement. I've sold some first-gen players with CDM that behaved this way.

Theoretically can be addressed if you tear down the motor, but not a simple task and there's risk of ruining the motor in the process. In that situation you're better off just using it regularly & remembering to power it up in advance of a listening session.

John
 
Most likely the plastic (teflon) bearing supporting the spindle axle.

A well known issue with CDM0 and CDM1 drives. Please have a look here : http://www.technikundnatur.eu/revox-mehr/das-cdm-1-laufwerk.html

I have bought a spare one just in case my Revox B225 fails.

Bought it from this guy in the link above, he had a small batch fabricated as the part is unavailable from Studer nor Philips.

A really nice bloke :yes:

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Thanks for the tips and the elaborate info on the spindle motor and bearing!
I will have a look at the spindle section.
After some further testing I observed that it does take all discs, but only after reinserting them several times (and being warmed up).

@dimanag: This is the exact CDM-1 mechanism I have (and player):
http://www.vicol-audio.ro/studer_a727.php (see third picture below, left)
 
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There is a service modification recommended by Studer, to increase the range of the tracking servo on the A727 with early serial numbers, so it will play dished CDs more reliably.
Check ftp.studer.ch for A727 service bulletins, & see if yours is in the range of those tht the mod applies to.
 
Hello Cielo,
I can see now! This is a new version of cdm1 for me!
It has a diferent pcb than the athers cdm1 i own. Indeed one electrolytic and the others are polyester!
I still beleive that your problem is related to a capacitor isue!
You say that after a warm-up period the player perform well. That means that the laser unit is ok and the spendle motor is ok too!! Maybee not in perfect condition but OK!
Also you say that you changed a lot of capacitors! Did you change the capacitors in the power section? Especialy the 3 big frako capacitors near the blue plug as shown in the 2-nd picture of the link? ( if i am corect, 2x2200uf and 1x1000uf)
If you have done already, i am out of any useful idea!!

I am sure you will succed with all the help from the members of AK!
 
Sorry, but warming up aged caps that have leakage or other issues isn't typically going to make them work correctly again.

The advice from Thierry and steerpike2 is on the money. My suggestion on the spindle motor having difficulty getting up to speed when cold comes from another of the acknowledged Studer and CDM experts here on AK, Tinman. These guys have tremendous experience on the mechanism in question.

Capacitor failures on these machines are also well-documented, but that condition doesn't match the behavior the OP describes.

John
 
Thanks again for all the useful advice:)!
I have a feeling it is indeed the spindle motor bearing/ height issue as described above.
I think i'll either have the bearing replaced or find a donor cdm-1, and keep my own for spare parts. Depends a little on the cost.
Thanks for the tip on the mod, mine does fall in the serial range that can benefit from the mod, so i'll have that done too.
Thanks again all for solving the mystery:)

Much appreciated!:music:
 
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