CD player not recognizing disc

jarthel · 26th March 2005, 02:56 AM

When I insert a CD, it just say "No Disc".

It was working 1 minute and suddenly the player stop working.

I opened the chassis and have traced the wires for the motors.

When I open the tray, the voltage going to the tray motor jumps from 0V to -2.5V. When I close it, it jumps from 0V to +2.5V.

I know that for a CD to be recognize, the player does an initial spin after closing the tray. This is not happening for my player. When I measured the voltage going to the motor that spins the CDs, it remains constant at 30mV.

Any ideas?

Thanks for the replies.

ps. from memory it uses the PHILIPS CDM1210 transport if that helps

hacknet · 26th March 2005, 05:33 AM

its probably a wonky lens. the symtoms all sound right...

jarthel · 26th March 2005, 11:40 AM

Would cotton with some isopropyl alcohol works?
---------
I still have my doubts the lens is at fault. For the player to recognize the CD, the CD spins for a short time after the tray is closed. During this spin process, the lens would then works its magic to recognize that the CD inserted is an audio CD. Since the CD is not spinning, the lens is never given the chance to work.

These are just assumptions though but it seemed logical to me.

tubenut · 26th March 2005, 05:14 PM

whereas CDM4 spin before focus.
Please check the limit switch(es) on the loader tray.
The switch is what initialises reading of TOC.

Good luck

jarthel · 26th March 2005, 10:32 PM

Quote:

Originally posted by tubenut
whereas CDM4 spin before focus.
Please check the limit switch(es) on the loader tray.
The switch is what initialises reading of TOC.

Good luck

where will I find them? How will I identify this switch? Thanks

tubenut · 27th March 2005, 12:02 AM

Look near the front and back top right edges of the loader (CD face plate facing you). I am not familiar with the 12.XX versions of Philips lasers.
Look for 3 brass terminals. Generally only 2 terminals are wired up.
If you manually slide the tray open and closed, look for a plastic "finger" that gets pushed in and out. CDM4 uses 2 switches, one to sense open and one senses closed. CDM9 does this with one switch at the top front right of the loader.
On the CDM4/19 this switch is a PCB mounted push button below the mech linked to the tray with a complex lever system.

Sliding the tray in and out and looking carefully at what moves and pops in and out of place there should be a good chance to ID the switch. Look for wires going to the PCB from the mech. There are only a few sets:
Spindle motor, Tray motor, Laser (but that is a foil) and the tray switch (if not a pcb mount affair)!

If you want to clean the lens use distilled water, isoprop can take some protective/glare coat of the lens according to some on this forum!!! If you have none at hand, boil a kettle and catch some steam on a cotton bud..

jarthel · 27th March 2005, 01:57 AM

thank you. I'll try that

26th March 2005, 02:56 AM	#1
jarthel diyAudio Member Join Date: Jan 2002 Location: somewhere in Australia	CD player not recognizing disc When I insert a CD, it just say "No Disc". It was working 1 minute and suddenly the player stop working. I opened the chassis and have traced the wires for the motors. When I open the tray, the voltage going to the tray motor jumps from 0V to -2.5V. When I close it, it jumps from 0V to +2.5V. I know that for a CD to be recognize, the player does an initial spin after closing the tray. This is not happening for my player. When I measured the voltage going to the motor that spins the CDs, it remains constant at 30mV. Any ideas? Thanks for the replies. ps. from memory it uses the PHILIPS CDM1210 transport if that helps

26th March 2005, 05:14 PM	#4
tubenut diyAudio Member Join Date: Nov 2002 Location: South Africa, Jhb	Depends...Check the limit switch, also some mechs focus first, then spin like CDM9 whereas CDM4 spin before focus. Please check the limit switch(es) on the loader tray. The switch is what initialises reading of TOC. Good luck

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Disc Tray problem on DVD player.	ashok	Everything Else	2	18th September 2007 06:48 AM
Arcam Alpha 7SE CD player not recognizing discs	gazsp	Digital Source	3	3rd August 2007 08:51 PM
Converting CAL CL10 5 disc player to a single disc player	stoolpigeon	Digital Source	0	27th May 2007 02:25 PM
Thorens Disc Player	exurbia	Analogue Source	2	30th May 2005 10:39 PM
CD Player doesn't detect disc sometimes	Gartak	Digital Source	4	3rd January 2004 12:58 PM

New To Site?	Need Help?
Register to Participate Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

26th March 2005, 05:33 AM	#2
hacknet diyAudio Member Join Date: Nov 2002 Location: sg	its probably a wonky lens. the symtoms all sound right...

26th March 2005, 11:40 AM	#3
jarthel diyAudio Member Join Date: Jan 2002 Location: somewhere in Australia	Would cotton with some isopropyl alcohol works? --------- I still have my doubts the lens is at fault. For the player to recognize the CD, the CD spins for a short time after the tray is closed. During this spin process, the lens would then works its magic to recognize that the CD inserted is an audio CD. Since the CD is not spinning, the lens is never given the chance to work. These are just assumptions though but it seemed logical to me.

27th March 2005, 12:02 AM	#6
tubenut diyAudio Member Join Date: Nov 2002 Location: South Africa, Jhb	Look near the front and back top right edges of the loader (CD face plate facing you). I am not familiar with the 12.XX versions of Philips lasers. Look for 3 brass terminals. Generally only 2 terminals are wired up. If you manually slide the tray open and closed, look for a plastic "finger" that gets pushed in and out. CDM4 uses 2 switches, one to sense open and one senses closed. CDM9 does this with one switch at the top front right of the loader. On the CDM4/19 this switch is a PCB mounted push button below the mech linked to the tray with a complex lever system. Sliding the tray in and out and looking carefully at what moves and pops in and out of place there should be a good chance to ID the switch. Look for wires going to the PCB from the mech. There are only a few sets: Spindle motor, Tray motor, Laser (but that is a foil) and the tray switch (if not a pcb mount affair)! If you want to clean the lens use distilled water, isoprop can take some protective/glare coat of the lens according to some on this forum!!! If you have none at hand, boil a kettle and catch some steam on a cotton bud..

27th March 2005, 01:57 AM	#7
jarthel diyAudio Member Join Date: Jan 2002 Location: somewhere in Australia	thank you. I'll try that