| Tubeee |
Hi all pro,
There are two vars(potmeter) combo with CDM-4 laser pickup system (on the pcb beneath the CDM-4), 4K7 and 22K. As I know these VARs are for the adjustment of laserdiode output and focus.
Questions are:
How to make precisely adjustment. Does anyone has related service manual?
If I change a new CDM-4, do I need to re-adjust these var to a correct value? (I think my CDM4/19 is dying)
need your kindly help.... |
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| Cobra2 |
Having nothing better to do(?), I took the old laser out of my CD-16 (CMD4-d36) and swapped the internals(laser) from a new CDM4.19. :bigeyes:
Only the platter-motor differs (exept the metal...):)
And everything works well, playing now...
Arne K |
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| Tubeee |
Hello Rudolf Broertjes,
I just search your previous post:
http://www.diyaudio.com/forums/show...0456#post120456
I think that's what I want to know now:
| quote: | | I have the adjustement procedure for tracking & focus with the two test points (50mV and 400mV). |
Where is these two test points: (or which registors?)
50mV is for tracking (laserdiode output)
400mV is for focus.
Is this done by using amp-volt meter to measure specific registor and check the amp cross it?
thanks |
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| zygibajt |
Hi,
Any one knows where the test points for this 50mA and 400mA are?
I got the CD-player where someone turned two trimming pots all the way up!
Bartek |
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| Cobra2 |
I guess it will be on different location in different players...
What make & model?
Arne K |
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| zygibajt |
There are always 22K and 4,7K pots and all the chips are usually the same.
The model in question is Marantz CD 883 but I have a couple of other ,diffrent machines and with CDM4/19 laser/drive it's always the same.
In fact this Marantz CD 883 is identical inside to the Marantz CD 65MKII ,just the same main board.
I have similar procedure for CDM 2/10.It goes ..."measure acros this resistor near that chip...and so on"
I need similar procedure for CDM 4/19
Bartek |
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| Bricolo |
| Is the procedure the same for all CDM4 based machines? |
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| zygibajt |
| quote: | | Is the procedure the same for all CDM4 based machines? |
I suppose it is.Chips and topologies are the same.
If any one knows it please share it with me.
Bartek |
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| rbroer |
Here you are :cool:
Designators can/will differ between several versions.
Just look for similar valued resistors on the pcb;
Many old Philips players can be measured near top left of transport. |
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| zygibajt |
| Many thanks Rudolf :) |
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| DoctorWho70 |
i have a cdm 4-19 in my cd 10 that have problems to read toc to many years... after two minutes this problems disappears...
i want to check it , but i've not understand where i have to check the tensions...
first point) the schematic tells that i've to adjust 3501 to 50mV, but in the schematic 3501 is a fixed resistor... and where i have to measure this voltage? across the resistor?
Maybe i have to trim the 3520 (4.7k trim) and measure across the 3501? (probably i think this is correct... but i don't want to kill my cdm... :) ).
second point) trimmer 3568 22k, the schematic tells: in combination with 27 400mV... but where? in the test point 3829 (across the capacitor 470n 2561)?
Thanks in advance for any response and very thanks to Rbroer for the piece of schematic...
question for Cobra 2:| quote: | | .....and swapped the internals(laser) from a new CDM4.19. |
Where have you found a new cdm 4-19 ??? ;)
Do you know where i can find a new laser or some spareparts for my cdm4-19??
Thank you...
bye to all |
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| zygibajt |
Halo to all.
I finally managed to adjust my cd player (big thanks to Rudolf).
All the resistors and caps values are exactly the same as Rudolf posted in his schematics but the numbers on my PCB were totaly diffrent.
A little instruction is needed becouse the pictures are not 100% clear.
50mV has to be trim with 4,7K pot and measured across 4,7K resistor (points "1" and "2") and 400mV has to be adjusted with 22K pot on point "27" to ground.
I found the 4,7K resistor on my board and "27" point on my board happend to be the pin number 6 of TDA5708.
These two parameter vary from one CD to another and from track to track.I used the newest,best condition CD I had in my collection and adjusted on the beggining of the first track.
Also strange 3029 point/part on the way to "27" on the picture didn't exist on my player at all.Rudolf said It might be some pin or test point,but no such thing on my board.
I just thought some may use my expirences.
All best
Bartek |
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| DoctorWho70 |
| quote: | | I got mine from "till" ... |
Sob...:bawling: , thanks for response...
anyone know a place to find a laser pickup for a CDM4-DM or something where dismount a compatible laser ??
Thanks for the explications... in next days i'll check my cdm and i'll write the results...and the differencies.. maybe it needs to someone other...
Bye |
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| Jocko Homo |
If you are having trouble reading the TOC, you can bring up the laser current.
But............
Be careful. It does not take much of an increase to make a big difference. I believe the spec is 50 mV +/- 5 mV across whatever resistor it is. If raising it close to the limit doesn't help, then raising it more to make it work may burn it out.
But if it is already useless..............then you may not have much to lose.
Jocko |
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| DoctorWho70 |
| quote: | | But if it is already useless.... |
:D at the moment my cd is use-ful... i have to wait a minute and try to play the cd many times when the cd is cold for having the TOC... after this it seems to work perfectly, no skips or other kind of problems... so i don't want to worsen the situation... it's many years that this cd work in this mode.
When i purchased it, after only a month, my laser say byebye and i had send it for repair in warranty.
When it returned, after not many monts, it was afflicted by this problem, and it's affected at now as well, but it's not less than 8-9 years that this problem exists...
I think that maybe the tecnician hasn't done a good work... so i can check now the voltages... i have also to remove the bad out stage of the 2 tda1547 for a D1-like stage... in the meantime i am searching a new laser for the future... but seems that this ******in' laser costs more than gold... and there is very few pieces in all the world...
Bah...
Thank you Jocko... (are you a fan of the twisted sisters ??? :D they remember me when i was young.... 15 years ago...:bawling:)
If someone has a service manual for the cdm4 to share it will be a great thing...
Bye to all |
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| Jocko Homo |
I have some manual for various flavours of those things. I always found them to be of little value.
Jocko........more a fan of...........DEVO...... |
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| Elso Kwak |
| Hi, The 50 mv is the only sensible adjustment you can do on these lasers. If it still not works the laser is kaput and you will need a new one. It is very important the subchassis with the laser and platter does not touch the case anywhere.:cool: |
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| DoctorWho70 |
Thank you very much to all... ;)
this is a very useful forum...probably the best i've ever seen in the web...
Bye to all |
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| zygibajt |
I got some more information from my fiend who was servising those CDM's for a quite long time.
He told me to make the adjustment after the player is warmed up,let's say playing on repeat for 2-3 hours.
He also told me that it would be the best to use some special service CD disk that has a special tracks for those adjustments.
Sony and Philips have these kinds of CD's.
The reason is many parameters differ from CD to CD and even a brand new ,original CD may not be the best for precise adjustment.
Bartek |
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| DoctorWho70 |
Do you think that i'm going to make a mistake if I use one of my cd, one that seems not to have a good TOC reading, to make the correct adjustement?
when you speak of differencies about various CD, do you mean some mV..?
thanks
Bye :) |
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| zygibajt |
Yes,
You adjust 400mV for one CD ,put another one and the meter will show 520mV. :) |
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| DoctorWho70 |
And what about the other adjustement?
the 50mV have to be stable in my opinion... I think that is not correlated to the cd used... it's probably a power regulation of the laser power that adjust the current into it... i'm thinking correct or not?
First of destroy my precious cdm :hot: i have to know a little bit more...
Bye and thanks to you ;) |
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| DoctorWho70 |
| quote: | | it's probably a power regulation... |
I think that is not correct because watching better the schematic d1 and d2 are receivers...
Anyone has a complete schematic of a Cdm to share? |
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| zygibajt |
50mV is more stable.It doesn't change from CD to CD but it changes slightly from thr beginning of CD to the end.
Bartek |
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| zygibajt |
What is interesting in the link above?
Exchanging electrolitics caps?
Sure it's a must.What would you expect from 15 years old el. caps?
Bartek |
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| DoctorWho70 |
for me is interesting because i'm not experienced of laser units... i tweak audio equipment only for hobby, normally i work on micros, industial electronics and related controls to realize cards for others... audio for me is only a hobby... so in some arguments i'm very ignorant... :rolleyes:
So now i know that is better to change also all the elecrolitic caps in the laser unit :) , next week i'll dismount all and check the el. caps... that probably have to be low ESR...
thanks Bartek
Bye
PS for Fin..| quote: | | CDM4/19 is available from Lubor at about 50 Euro IIRC. |
at the moment they replied me that they hasn't any cdm4/19... also they are looking for this units...
Thanks for the info |
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| ZuMbAiU |
| Guys this thread is very useful for me and my Marantz CD-65DX with CDM4,but will be great if anyone can help me : what is this part : 3829 ,because I can find 3828 ,but in my player I can find may be and 3829 with more info.Thanks!:smash: |
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| jean-paul |
| quote: | Originally posted by DoctorWho70
at the moment they replied me that they hasn't any cdm4/19... also they are looking for this units...
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FYI I have several new CDM4 for sale. |
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| Elso Kwak |
Just stick to the 50mV adjust . That's all you can do!
:cool: |
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| Gasho |
| quote: | Originally posted by jean-paul
FYI I have several new CDM4 for sale. |
Price please? I have several players with CDM4/36 , they work , for now. |
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| Gasho |
I adjust laser current , by listening. I put orginal disc , turn trimer way down , and slowly rise the current until TOC is readed , then push play button and listening to music while turning current down. On some ponit the distorsion apears , then I slowly rise current up.
I do the same on bad copyed discs.
The laser is allways on when player is playing , but when you change laser current, signal strenght that comes out of photo diode is changed. But there is a low limit that decoder electronics need.
All cd´s don´t have the same reflection power. |
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| ZuMbAiU |
| Gasho I can`t adjust the laser by listening,because my player can`t read any CD two days now.Will be great if anyone can give me approximately any value in Ohms for this two trimers when his player play good. When I can adjust with listening my player while he can read any CD.Thanks!:smash: |
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| Gasho |
Leave laser alone.
Didi you resolder all solder points on PCB of player? That can be problem. |
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| ZuMbAiU |
My laser is OK.I want only setting-up,but I can`t- accidentally I am to blame for this that he can`t read any CD.
I want setting-up the laser -the player is Marantz CD-65DX with CDM4- but I can`t find this read points for the voltage on my player. I can setup the laser by listening like you,but I want only your value of this two trimers(22K,4K7) ,because now my player can`t read any CD ,and nobody for the moment can`t help me with any picture of the CDM4 with the voltage-read points or any other instructions. And YES ,I `am sure that my laser is OK:smash:
Thanks!:xeye: |
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| ZuMbAiU |
Pls guys and may be
Gasho:
I can tune-up the laser with many CDs from many brands on hand with very small help from you.Pls give me the value for this two trimers ( 22K and 4K7) from your player and I can make only very fine tuning for me.If you can`t in the thread I have e-mail in the user info. Pls- It`s very importantly for me and my player.I love this player in human decency but for me now he is dead:bawling:
My CDM4 is new from one bulgarian shop for old parts.:smash: |
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| Gasho |
Focus trimer trim to some midpoint position , but the laser bias is crutial. Do not overtrim laser bias , you can damage it.
I did not measure the trimer position value , the player is gone by now to his master:cool: |
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| ZuMbAiU |
Anyone have in his hands any player with CDM4?
If anyone can give me the value for this two trimers -4K7 and 22K will be very,very,really very great ,because I can`t tune-it for any CD.
Thanks:bawling: |
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| DoctorWho70 |
Send me a pm with your e-mail, i can send you some parts of the service manual of my marantz cd10 which is mounting the cdm4, in my case is a d36 (metal diecast) but probably the electronic is the same.
I solved my old problem of toc reading error at cold start changing all the capacitors around the focus circuit...
I'll send you the service maual tomorrow night... this night and tomorrow i'll be out of home... be patient until tomorrow :D
Bye
DoctorWho70 |
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| DoctorWho70 |
| quote: | Originally posted by jean-paul
FYI I have several new CDM4 for sale. |
Thank you ... :) i'll take you in consideration...
keep me one for the future ;)
... ;) i'm joking, fortunately for the moment i've solved the cold start problem with my cdm4-d36... a *******in capacitor... not electrolitic in the focusing circuit, probably the start capacitor, but i changed a buck of theese polyester capacitor in the card, i noted that placing the probe on the starting signal (a rc circuit) the cd made infinite errors in toc, removing the probe the laser read the toc... so i've changed all the capacitors in the card and for the moment the problem is not solved at all, but at 90%... but after an error sometimes, the cd goes well... a big improvement respect to a 5 minutes of error continuous.. |
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| ZuMbAiU |
| Hi DoctorWho70! Now I know that you have CDM4.Can you help me with any value for the two trimers-4K7 and 22K ,because I can`t hit the precise position for this two.The cold start is in the big capacitor in my CD-65DX-6800uF/16V.In the schematics I can`t find any error ,but when the player start with 10000uF/25V(new capacitor) I haven`t this problem.Pls help for my CDM4-I can`t sleep like a log when my CD-65 is dead for this moment :bawling: |
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| DoctorWho70 |
I sent to you a 5 mb file i hope that your mailbox will be big...
Good luck!
I tried in the past to apply some el cap across the voltages in the servo and laser board without luck...
the probe problem for me was very strange... unfortunately after that the toc problem have been improved after the small caps replacement i didn't find any other time to dedicate to other tests, for the moment i go on without touching anything else...
ByeBye
DoctorWho70 |
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| ZuMbAiU |
Thanks
DoctorWho70 ,but the result is :
nothing with the new-old laser :bawling:
nothing with the brand new CDM4 :bawling:
I buy the lasers from one shop for Philips CD582= Marantz CD65DX
Pls if anyone can ,I attach one picture of the CD582 like my CD-65DX.
I can`t find the read points for the tuning of the two trimers- 22K 4K7.
If the answer is top-secret I have e-mail in the user info.Thanks! |
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| DoctorWho70 |
this image is of the DAC and filter board, you are watching the wrong card, the trimmers of the laser adjustements are on the card under the motor and the laser head, all the CDMs have this electronic card on-board.
Check the service manual and you will see how the cdm is constructed, to accessing at your electronic, maybe you have to dismount the complete cdm.
In my cd10 there is a hole closed by a metal plate under the chassis where you could trim the pot without dismounting all, i don't know in your cd...
Bye
DoctorWho70 |
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| ZuMbAiU |
And what is this?I try to tune this two trimers in the attachment - 22K and 4K7.This is the problem in my case:
Default value : The player is Ok
I try to tune up this trimer : the player can`t read any CD
And now if anyone can help me: what is my problem.I love my player like ...
:bawling:
EDIT : if anyone can give me the value of this two trimers on my mail will be great: I am may be very stupid,but this value is for? :rolleyes: |
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| Gasho |
Change trimers with new like Bourns ones. Maybe they are faulty.
I will buy all new chips exept DAC ,filter and microprocessor ones , and change one by one. My CD 304 mk2 refuse to play ,an error is hidden i one of them. |
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| ZuMbAiU |
| My laser work great on one Philips CD852.I am to blame for this big problem.If my CDM4 is like the default with the default trimers position-no problem,but now I wait one week and I can`t turn on my CDM4 again with any settings for this two trimers:bawling: |
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| ZuMbAiU |
Guys-the big question of my last week :smash: :smash: :smash:
What is the function of this two trimers on the picture? I work with this two trimers and the problem is in this two devils!
I wait for any help one week:bawling: :bawling: |
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| DoctorWho70 |
ok, your electronic is different from mine, but what you can see on page 10-11, regarding the sheets i sent to you, probably you have it in the card of your cd (a single card), in my cd there are many cards... but what you see on page 10-11 is probably the same that in your cd (if it's a cdm4) with the only difference that it is integrated in your main board.
so, read at page 45 about the regulations, and read also from page 40 to 46, giving an eye to the schematic of pages 10-11...
try to reconstruct your part of the schematic about your two trimmers and check if the circuits are similar.
if your mech is a cdm4 i'm quite shure that the circuit that controls the focus motor and the laser power need to do the same thing, also if the circuit seems to be quite different...
I don't know your cd, so this is the maximum help that i can give you.
Good luck
DoctorWho70 |
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| henkel |
Dr. Who,
You have mail. |
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