CD player does not detect CD - pickup problem?

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C

cm

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Joined 2003
I have two Philips CD players both dying in the space of one month. In both case, everythng works except that the disc does not spin as the CD was not detected. Has anyone ix this kind of problem before?

On one of the CD player, the mechanism is a CDM12.1/15. I have checked all the wiring, motors etc. The %^& thing just does not see the CD. Maybe the diodes are dead and they cannot see the CD at all.

I have the service part number for the CDM12.1/15. Internal Philips speak is 12NC number ( ex-Philips staff speaking ). If all else fails, then I will buy a new mechanism from the service centre.
 
C

cm

Member
Joined 2003
The CDM12.1 communicates with the CD player controller via a three wire interface. I have traced the three lines to a microcontroller on the CDM board. I wonder if the commands and timing are standard across all CDMs. If so, then I can ditch the CDM12.1 ( the quality of the board is crap - with obvious rework of lifted traces ) and replace with the CDM4 or CDM 9. Or even the CD Pro!

Anyone tried swapping this kind of interchange before?
 
E

EDUM

Member
Joined 2003
Hello CM,

Before attemting open heart surgery try the first aid kit first.:D

The Singapore service centre should be able to deliver the service docs you need. In there you can find a complete procedure how to test your CD-players. After finding the fault you can always decide to replace a complete unit or repairing the faulty part.

success!

Ward
 
guido

guido

Member
Joined 2002
members.home.nl/baltusg/
cm said:
The CDM12.1 communicates with the CD player controller via a three wire interface. I have traced the three lines to a microcontroller on the CDM board. I wonder if the commands and timing are standard across all CDMs. If so, then I can ditch the CDM12.1 ( the quality of the board is crap - with obvious rework of lifted traces ) and replace with the CDM4 or CDM 9. Or even the CD Pro!

Anyone tried swapping this kind of interchange before?
Click to expand...

CDM4 / 9 usually come only as the transport. All the decoding chips are usually on the main pcb including laser and radial control (TDA57xx or newer) and a servo microcontroller, which is programmed for the particular CDM type (see an other recent post for this).

Unless you find a (pro?) unit with all of the above on-board AND which has the same interface as your CDM12.1, you cannot do this. I know there is a CDM2 type with all the chips on the pcb, but i have never seen this (the CD650 CDM2 only has no servo microprocessor on board).

Best advice is indeed to find a working CDM4/9 player or fix an old player (make two out of one, got a CD60 for 45 euro by doing so)

Greetings,
GuidoB
 
C

cm

Member
Joined 2003
Looking around on the web, I found a site that mentions the three wire interface I talked about. It seems that from CDM12 onwards to CD Pro, a standard interface is used called the DSA interface. The site has details, as well as a simple interface via a centronics port and a DOS program to control the mechanisms.

This is fantastic. I can now buy a broken down CD player which uses a CD12 mechanism ( crap ), and then connect it to a CD pro instead. I get the user interface, remote and display of the host CD player but the performance of the new bionic heart - CD Pro without the need for a lot of hard work. Here comes the 6 million dollar CD player!

http://www.daisy-laser.com/tech2.htm#DSA specifications
 
A

Alvinttt

Member
Joined 2003
For Diy member in Singapore CM

Hi, there I'm also from Singapore and would like to learn more about replacing the cdm12.1 with the cd pro, cause I've got a busted CDM 9pro, the problem is the turntable, its warped. Is there a way to replace it or where can I get a Cdm in Singapore. I've try the usual Sim Lim Tower and they don't sell it. Need help Urgently, can I contact you in anyway.

Cheers Alvin
 
K

kello

Member
Joined 2003
cm said:
I have two Philips CD players both dying in the space of one month. In both case, everythng works except that the disc does not spin as the CD was not detected. Has anyone ix this kind of problem before?

On one of the CD player, the mechanism is a CDM12.1/15. I have checked all the wiring, motors etc. The %^& thing just does not see the CD. Maybe the diodes are dead and they cannot see the CD at all.

I have the service part number for the CDM12.1/15. Internal Philips speak is 12NC number ( ex-Philips staff speaking ). If all else fails, then I will buy a new mechanism from the service centre.
Click to expand...

for you case 1,you can to do:
1:clean the lens (carefully!!! with 90%-100% alcohol and cotton tool)
2:adjustment the resistor of pick-up a bit,try read the good quality CD again,is working you can stop,is not, you can try again for a bit or more.
3:replace new one pick-up


for you case 2 ,like for case 1 process,if not,you can replace a new PHILIPS's pick-up.some model can use:
CDM12.1
VAM1201
VAM1203

NOTE:all the process only for save the life of old pick-up,the pick-up to be die on 3 day or 3 month after ,not for long life.

one way for correct repair the CD player: replace the old pick-up.

for any operation of pick-up,must take care of ESD!and don't touch the lens!


my job is for CD/DVD pick-up technical.
 
jean-paul

jean-paul

Disabled Account
Joined 2002
1:clean the lens (carefully!!! with 90%-100% alcohol and cotton tool)
Click to expand...

Wrong ! Use distilled water with a mild detergent ( dishwashing soap ). On some lenses the alcohol damages the coating on the lens. Certainly with plastic lenses the advice for using alcohol may be the final stroke for the laser.

my job is for CD/DVD pick-up technical.
Click to expand...

For what brand if I may ask ?
 
K

kello

Member
Joined 2003
Hi!Jean-paul

jean-paul said:


Wrong ! Use distilled water with a mild detergent ( dishwashing soap ). On some lenses the alcohol damages the coating on the lens. Certainly with plastic lenses the advice for using alcohol may be the final stroke for the laser.



For what brand if I may ask ?
Click to expand...


Hi!
for clean the lens of Pick-up,using the "alcohol"is right, but the "alcohol" not same the normal alcohol (ethanol,C2H5-OH), true name is "lsopropylalcohol",the chemic name are "C3H3O",our factory using this solvent for lens clean in every day,for plastic CD/DVD lens no problme is ok too.
for PHILIPS CDM12 serial's lens is ok I have been use.
for any glass lens is fit.

clean the lens must carefully with good skill (first for round,after unilateralism)don't damage the actuator!!! sometime incorrect operation to be bent the support wires of actuator .
in CDM12.1 or VAM1210 the actuator aer made by plastic so normal to do are ok.


our 3 factorys (only for CD/DVD pick-up or CD/ DVD modules manufacture), shipment over 200,000pcs per day, the brand list with SONY or PHILIPS, I'm sorry for the name.


Of course,some alcohol to be damege the lens's coating of some kind lens of different manufacturer.

Other: I think using the distilled water without any other for clean is OK are good choose.


;) :)
 
C

cm

Member
Joined 2003
After struggling with both Philips CD players as mentioned in the firts post, ( one is a CD player and the other is a mini sound system ) and replacing both the CDM12.1 with new VAM 1202s, both the crappy stuff still says no disc.

Swapping back the older CDM 12.1 into the CD player and tweaking the variable resistor, the CD players comes back to life again, but only for a few days.

I am rapidly coming the conclusion as Jean Paul - scrap these crappy stuff. If new lasers cannot work on two different systems, there must be other common problems. I noticed that the head moves up and down a couple of time but is still unable to detect. I will try replacing the TDA 1300 lazer diode amp and it it still does not work.........philips:smash:

Both systems uses the same circuits, TDA1300, SAA 7372s and 3 TDA7073.

Any suggestions from anyone that is constructive before I go into a destructive mode?
 
jean-paul

jean-paul

Disabled Account
Joined 2002
for clean the lens of Pick-up,using the "alcohol"is right, but the "alcohol" not same the normal alcohol (ethanol,C2H5-OH), true name is "lsopropylalcohol",the chemic name are "C3H3O",our factory using this solvent for lens clean in every day,for plastic CD/DVD lens no problme is ok too.
Click to expand...

Isopropylalcohol is safe ( it is the main component in lens cleaner for cameras ) but in general people misunderstand when just the term "alcohol" is used. The chance that they will use (m)ethanol is high hence my advise to use distilled water.
 
georgehifi

georgehifi

Member
Joined 2003
lightspeedattenuator.com
cm said:
I have two Philips CD players both dying in the space of one month. In both case, everythng works except that the disc does not spin as the CD was not detected. Has anyone ix this kind of problem before?
Click to expand...

Is this with burnt cd's or with retail cd's?
If you look at the difference,
1: left side retail.
2: middle gold burnt blank
3: right normal burnt blank
It's a wonder lasers can read anything but retail ones, and I bet the error correction is much higher on the burnt ones.

https://www.iasa-web.org/sites/default/files/tc05-fig20.jpg

Cheers George
 
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