 Posted: Fri Apr 10, 2009 5:00 pm Post subject: |
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You are Welcome.  |
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| Posted: Fri Apr 10, 2009 7:01 am Post subject: |
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| Hi all, vtech,
Good news. The saga has ended! Today I assembled my new CDM12.1 laser module. I then put the carousel, servo PCBA, main PCBA and all cables back where they belonged - good thing that I had taken pictures of every sub-assy. before taking it apart - and then switched on the player. And playing it did! It plays all tracks effortlessly like it used to do when it was new: no skipping, very quick search-and-play behaviour. Fantastic! I did not even have to use a scope or a DMM. I guess that means that I no longer need a service manual. Allthough if I could get a hold of one for possible future reference, that would still be good. Thank you, vtech, for kindly sharing your insights and expertise. That was much appreciated! Sincerely, stijnsg |
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| Posted: Fri Apr 10, 2009 1:05 am Post subject: |
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Hello vtech, Thanks for that tip. The ribbon cable of my new CDM12.1 laser assembly has not got such a shorting solder bridge. Instead it has a metal clamp - lake a paper clip - on the contacts of the ribbon cable for that same purpose of protecting the laser diode against static discharge. By the way, the CDM12.1 that I bought, is factory new, not 2nd hand. There are still a few factories manufacturing these. If you do a search on the web, you'll easily find them. Sincerely, stijnsg |
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| Posted: Thu Apr 09, 2009 2:58 pm Post subject: |
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| ..just remember to remove the "shorting solder bridge" before reassembling the unit.
It is usually noted on a piece of paper with the new part but since you mentioned of used parts, it may or may not be there? It is usually a solder bridge put somewhere along the ribbon assembly to short out two adjacent traces together to protect the lase diode from static while not in circuit. It is normally obvious to the naked eye & must be removed after connecting the ribbon. |
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| Posted: Thu Apr 09, 2009 12:17 pm Post subject: |
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The player is now disassembled, almost as it would be on a factory assembly line. There is now way avoiding this, as you can only get full acccess to the laser unit once you disassemble the CD carousel, which in fact requires a full disassembly of the player's "intestines". By the way, I noticed that the servo PCBA is mounted underneath the carousel assembly?!?! Who in their right mind would design a product in this way? It is completely inaccessible for any quick measurements.
I got myself a replacement CDM12.1 laser unit assembly, that is incl. the 2 motors. Although I found both motors in the original assembly to be functional, I took a gamble assuming that the laser itself might have reached its EOL. Anyhow, the cost of this factory new CDM12.1 allowed for a bit of a gamble. By tomorrow I should know whether a new laser unit can bring this player back to life. If not, than at least I have learned how to disassemble and assemble a CD changer 
Fingers crossed for now. |
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| Posted: Thu Apr 09, 2009 5:06 am Post subject: |
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| No kidding...I know what you mean about "unserviceable crap" As a matter of fact we referred to a lot of them as "Bufallos".
Very unlikely that I'd still have the specific manual as I have pretty much discarded most of the paper manuals. In addition, the laser replacement was actually an assembly including both motors. Coming to think of it, the spindle motor was also notorious and you may indeed have a bad spindle motor. In any case you would have to replace it as a complete assembly. The Philips part number was 482269130278 which more likely has been discontinued or replaced by something else?--not sure This type of laser/motor mechanism was used on many different brands and was the number one failure item. In case of spindle motor failures, sometimes, depending on the severity, you could try to clean the motor's brush contacts by spraying something like freon TF inside the spindle or even spin it by hand a few times for a temporary fix. |
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| Posted: Thu Apr 09, 2009 1:41 am Post subject: |
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| Hello vtech,
Thank you for sharing your experience.
At least as far as Philips TV (alignment) service menus are concernded, I found them to be very helpful. As far as audio is concerned, I must admit never having tried one of their service menus as I do not own that much Philips audio anyhow.
In that part of the world where I am living, I indeed can buy replacement laser modules, although they are mostly 2nd hand. New ones (clones) can be found as well, but can only be bought in bulk which in my case is not economical. Yesterday I took a deep dive and disassembled quite a bit of the player. This player has not been designed with servicing in mind! Very unlike their earlier and European designed CD players. Anyhow, I now have limited access to the laser lens which I gently brushed with a cotton tip that I wet with distilled water (and not alcohol which effectively will damage some of the lenses). Like you indicated, it now will become a challenge to find a way to hook up the PCBA in such a way, that the laser unit will still be visible allowing me to check if it emits anything at all. Worst case I would have to make some extension cables for the PCBA. Then again, vtech, you seem to be well experienced in a.o. Philips repair matters. You would not happen to know how to get a hold of a service manual for CDC751? For free would be very nice (and kind) of course !
Sincerely, stijnsg |
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| Posted: Thu Apr 09, 2009 12:50 am Post subject: |
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| Having had to deal with a lot of Philips Audio/video products in the past, I can assure you that the "service menu" is just about as useful as a door knob!
In your case, it is very likely that the laser mechanism is at fault which makes it uneconomical to repair in the USA (I see that you are posting from a different part of the world--perhaps not the case there?) Anyways, the whole idea of Philips service codes/diagnostics required specific jigs/cables that had to come directly from Philips and in my experience, it was not very effective(w/ the exception of using it on their CD recorders) . Later on Philips devised yet another half-baked diagnostic system, "Compair" which required a windows based PC & yet another set of jigs along with software for all of their A/V products. I did use it mainly on their DVD recorders & while it did have useful features, Once again it turned out to be more of a toy. |
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| Posted: Wed Apr 08, 2009 5:10 am Post subject: |
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Hello jts1957, I do not plan on tweaking the laser. This is rarely required anyhow and more often than not will cause an early end of life of the laser. And without a service manual I would not know what to adjust: the entire PCB does not contain any pot-meters which makes tweaking without a service manual not straightforward. I have not cleaned the lens because it is not readily accessible. Furthermore, as nobody in this house smokes, it would be suprising for the lens to have become dirty. I am really in need of the service manual but have had no luck finding one so far. Regards, stijnsg |
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| Posted: Fri Mar 27, 2009 10:06 am Post subject: |
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| Have you tried cleaning the lens and tweaking the laser? | |