Focus on Marantz cd74 with CDM1

drews · 8th November 2005, 10:31 AM

Hi,
I have an old Marantz cd74 with CDM1.
Does anybody know how to set the correct parameter for CDM1 llaser (focus,adjust ecc ecc)?

Thanks
Andrea

drews · 8th November 2005, 04:15 PM

I only know that for adjust the laser output, I must connect DC voltmeter between the emitter of Q239 and the ground of chassis and adjust the potenziometer so the DC voltmeter reads 500mv +- 30mV.
In the pcb of CDM1 there are 3 potenziometer, one for laser out put, one for focus error adj and the other one for Focus offset adj.
Somebody know how check focus error value and focus offset?

Many thanks

Andrea

guytou · 8th November 2005, 09:40 PM

Hi , the best would to have the CDM-1 service manual ,I have seen a link about a danish site ,I think , but sorry i dont remember .maybe try a search with "philips"?

drews · 11th November 2005, 01:07 PM

When I close the door with a CD I can see from an angle that there is laser light. I can also see the laser flexing as is trying to focus. The motor however doesn't spin at all. Why?

The motor start only if i insert "Eric Clapton" cd, with other cd it doesn't start. If I wait one hour, so when the cd-player is warm, the motor start.
How is possible?

I have noticed that, if I tilt the cd while the laser is trying to focus, the motor start normally also if the CD-player is cold.

Thanks
Andrea

guytou · 11th November 2005, 10:25 PM

could be a lot of things . have a look here :

http://repairfaq.ece.drexel.edu/sam/cdfaq.htm

good luck .

drews · 14th November 2005, 09:35 PM

I solv the problem

At the bottom of the turntable motor there is a screw.
The value was so high(300mV) and the normal value shuld be 0 mV

Also the laser output was so high (650mV) and the normal value shuld be 500mV
Now the CDM1 play very good, like new

Thanks to ALL

Andrea

dariusku · 15th November 2005, 09:55 AM

Hi,
& own this Marantz too and preparing to tweak it.Have somebody a schematics or service manual ?
Thanks
Darius

8th November 2005, 10:31 AM	#1
drews diyAudio Member Join Date: Jan 2005 Location: Roma	Focus on Marantz cd74 with CDM1 Hi, I have an old Marantz cd74 with CDM1. Does anybody know how to set the correct parameter for CDM1 llaser (focus,adjust ecc ecc)? Thanks Andrea

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
mod cheap marantz player into great top load transport (cdm1 mkII) Long.	bryanj	Digital Source	4	28th January 2010 07:33 AM
Marantz CD74 laser trimpots	westerndigital	Digital Source	3	8th November 2007 07:33 AM
I2S from Marantz CDM1 possible?	Kohjin Yamada	Digital Source	4	29th July 2006 08:09 AM
Marantz CD74 skipping towards end of cd	matski	Digital Source	9	18th April 2006 10:00 AM
CDM1 or CDM1 MK2 In Revox B226S	jchou	Digital Source	7	16th September 2004 08:54 AM

New To Site?	Need Help?
Register to Participate Search 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

8th November 2005, 04:15 PM	#2
drews diyAudio Member Join Date: Jan 2005 Location: Roma	I only know that for adjust the laser output, I must connect DC voltmeter between the emitter of Q239 and the ground of chassis and adjust the potenziometer so the DC voltmeter reads 500mv +- 30mV. In the pcb of CDM1 there are 3 potenziometer, one for laser out put, one for focus error adj and the other one for Focus offset adj. Somebody know how check focus error value and focus offset? Many thanks Andrea

8th November 2005, 09:40 PM	#3
guytou diyAudio Member Join Date: Mar 2005 Location: marseille	Hi , the best would to have the CDM-1 service manual ,I have seen a link about a danish site ,I think , but sorry i dont remember .maybe try a search with "philips"?

11th November 2005, 01:07 PM	#4
drews diyAudio Member Join Date: Jan 2005 Location: Roma	When I close the door with a CD I can see from an angle that there is laser light. I can also see the laser flexing as is trying to focus. The motor however doesn't spin at all. Why? The motor start only if i insert "Eric Clapton" cd, with other cd it doesn't start. If I wait one hour, so when the cd-player is warm, the motor start. How is possible? I have noticed that, if I tilt the cd while the laser is trying to focus, the motor start normally also if the CD-player is cold. Thanks Andrea

11th November 2005, 10:25 PM	#5
guytou diyAudio Member Join Date: Mar 2005 Location: marseille	could be a lot of things . have a look here : http://repairfaq.ece.drexel.edu/sam/cdfaq.htm good luck .

14th November 2005, 09:35 PM	#6
drews diyAudio Member Join Date: Jan 2005 Location: Roma	I solv the problem At the bottom of the turntable motor there is a screw. The value was so high(300mV) and the normal value shuld be 0 mV Also the laser output was so high (650mV) and the normal value shuld be 500mV Now the CDM1 play very good, like new Thanks to ALL Andrea

15th November 2005, 09:55 AM	#7
dariusku diyAudio Member Join Date: Nov 2004 Location: Kaunas,LT	Hi, & own this Marantz too and preparing to tweak it.Have somebody a schematics or service manual ? Thanks Darius