Hi fellow enthusiasts, I’d greatly appreciate some input on the possible cause for this.
After I rebuilt the audio board and the main board and replaced all electrolytic and tantalum capacitors on them three years ago the unit worked well. It started to skip some weeks ago, and this quickly developed into the player being unusable.
As in 2020 I had not yet recapped the motor board and the display board, I did this in the last days. I was sometimes having an intermittent problem with the display not being lit after switching the unit on. That was remedied by the recap.
I also re-soldered all contacts going through the boards connecting the ground planes. Unlike the 104 this player does not have "griplets" but makes ground contacts with component leads which are soldered to the tracks on the solder side and to the copper ground plane on the component side.
I removed the solder and resoldered from both sides, paying attention that the connection was family established with the copper plane. I also resoldered all other suspicious joints.
The unit still skips however. It is reading the TOC, it does everything well, it is reasonably fast, I can choose tracks and go back-and-forth and everything seems to be functional. I sometimes it even plays for a quarter of an hour without disturbance but then again starts skipping and even stops playing the disc.
The lens seems clean. I am unsure where to look next. I don’t want to poke around in the dark.
The unit has a CDM0 drive, the one shown around page 18 of the CDM0 service manual. I also have the original Phillips test disk package. I even have a scope. But I am not very familiar with using it and doing these kinds of procedures.
As the player does sound exceptionally great and so far has been the reference in my system, I’d really like to get it going again, apart from the ambition to not give up on this fault.
I’d love some experienced opinion on this, and I’ll try to find the problem, although I won’t be able to dedicate very long hours to it in the next days due to work.
Thank you all.
After I rebuilt the audio board and the main board and replaced all electrolytic and tantalum capacitors on them three years ago the unit worked well. It started to skip some weeks ago, and this quickly developed into the player being unusable.
As in 2020 I had not yet recapped the motor board and the display board, I did this in the last days. I was sometimes having an intermittent problem with the display not being lit after switching the unit on. That was remedied by the recap.
I also re-soldered all contacts going through the boards connecting the ground planes. Unlike the 104 this player does not have "griplets" but makes ground contacts with component leads which are soldered to the tracks on the solder side and to the copper ground plane on the component side.
I removed the solder and resoldered from both sides, paying attention that the connection was family established with the copper plane. I also resoldered all other suspicious joints.
The unit still skips however. It is reading the TOC, it does everything well, it is reasonably fast, I can choose tracks and go back-and-forth and everything seems to be functional. I sometimes it even plays for a quarter of an hour without disturbance but then again starts skipping and even stops playing the disc.
The lens seems clean. I am unsure where to look next. I don’t want to poke around in the dark.
The unit has a CDM0 drive, the one shown around page 18 of the CDM0 service manual. I also have the original Phillips test disk package. I even have a scope. But I am not very familiar with using it and doing these kinds of procedures.
As the player does sound exceptionally great and so far has been the reference in my system, I’d really like to get it going again, apart from the ambition to not give up on this fault.
I’d love some experienced opinion on this, and I’ll try to find the problem, although I won’t be able to dedicate very long hours to it in the next days due to work.
Thank you all.
Lens came with the CD player. Majority opinion is that CDM0 lasers / lenses are not necessarily the weakest part in the chain, that's what I understand. The unit has been used a lot before I got it (lettering wiped off partially). The CDs I used are of good quality and clean, no scratches. They are the same that played fine three weeks ago.
Thanks for answering! I'd love some input from someone with dedicated early Philips experience, as those machines have their quirks and I only know some of them 🙂
Thanks for answering! I'd love some input from someone with dedicated early Philips experience, as those machines have their quirks and I only know some of them 🙂
Somewhere in these news letters was an article on repairing this problem. https://avahifi.com/pages/audio-basics-newsletters The problem has to do with the "clamping" system on the CD spindle. As I recall, the unit has a thrust ball bearing with a single ball that bears on a plastic part. over time the ball indents into the plastic and then causes wobble when the player is trying to run. The above mentioned article outlined a fix for the problem and advised against leaving CDs in the machine when not playing them, as it would cause this problem over time. Good luck with your repair.
it is not impossible that this is the problem but to find out it would be necessary to have a photo of the underside of the optical block because there have been some variants, some even have an adjustment screw under the pivot axis of the laser block and others no, but you can return the support plate, hence the request for a photo.
Thanks so much. Actually the clamp does wobble. Not sure if this is related, but looking at its wobbly movement this morning I asked myself if this could be part of the problem. I'll check out the newsletter, thanks @Donaldspace. Below are two photos of the underside of the motor assembly, hopefully it helps. I can take more. I have removed the motor board so often now, I can do it with eyes closed (or so it seems).
I think it's worth disassembling the pivot of the laser to see the condition of the ball and its seat, if it's worn and you don't have a spare part on hand, you can twist it slightly lower plate to raise the laser block slightly.
all very smoothly of course.
all very smoothly of course.
Ok. So I unscrew the central nut (in the photo)? Any small parts that can fly around and vanish forever if I do this?
The laser swings very easily.
This is another path to follow than to look at the puck / clamp (underside vs. above), right? So I have two tracks to follow here.
The laser swings very easily.
This is another path to follow than to look at the puck / clamp (underside vs. above), right? So I have two tracks to follow here.
I have a CMD0 laser block in my archives, I'll see before answering you, I don't work on it every day.
but from memory it is rather the two Allen screws that must be removed.
wait for my return for confirmation
but from memory it is rather the two Allen screws that must be removed.
wait for my return for confirmation
and it is not a matter of swing but a matter of high optics.
as it wears out, the pivot lowers the optics relative to the drive plate and therefore there is more and more distance between the optics and the surface of the cd
as it wears out, the pivot lowers the optics relative to the drive plate and therefore there is more and more distance between the optics and the surface of the cd
Ok, this is really helpful information. Thanks @huggygood for taking the time and looking it up. It seems a daunting task to dissemble the laser assembly... let's see if I dare to do it tonight 🙂
Ok got it. This seems plausible with the behaviour. I'll have a look now!
The nut turns with the bolt. It seems to need to be fixed from above (well, from below if seen from the bottom of the unit).
Instead of trying to raise the laser physically, would it not also be possible to change its focus a bit?
Instead of trying to raise the laser physically, would it not also be possible to change its focus a bit?
I found some very valuable information here: https://nanocamp.de/?cdm1-laser-service
@nanocamp restores and resells Philips TDA1540 and 1541-based players and parts. According to his description the problem could be missing lubricant in the bearing. So in any case I have to access the top of the assembly.
@nanocamp restores and resells Philips TDA1540 and 1541-based players and parts. According to his description the problem could be missing lubricant in the bearing. So in any case I have to access the top of the assembly.
The English language description of lubricating the bearing is here. He advises against loosening the two Allen screws as they set the beam angle and everything needs to be aligned if they have been removed. The guide linked below is for a CDM1 (I have a CDM0). The laser swing arm assembly seems identical among them, but the motor – and the way to mechanically adjust the focus – ist not (among other differences). If I make progress I'll report here.
https://dindiki.com/?cdm1-laser-service
https://dindiki.com/?cdm1-laser-service
I think I would be replacing those blue axial electrolytics before doing anything else tbh.
You also need to look at the RF signal on a scope before touching anything. Look at the amplitude and look at the general Q or quality.
Once you disturb the mechanical alignment of the arm then all bets are off 🙂 because you have introduced to many variables without first determining where the problem might be.
You also need to look at the RF signal on a scope before touching anything. Look at the amplitude and look at the general Q or quality.
Once you disturb the mechanical alignment of the arm then all bets are off 🙂 because you have introduced to many variables without first determining where the problem might be.
Hi Mooly! Thank you. Good to know you're around the corner helping out in my new adventure.
I had already replaced all electrolytics. Not one blue axial Philips cap remaining.
The photo I posted above is the state before replacement (taken in order to remember where all the cables go).
Unfortunately I have followed the advice given yesterday and removed the Allen screws which hold the Laser assembly. I put them back and the player reads CDs (and skips as it did before). Anyway it seems that I am at the foot of a steep learning curve again. And I will need to switch on that scope 🙂
So next step will be to check according to what you suggest. I am a bit short on time right now so this might take a while.
I had already replaced all electrolytics. Not one blue axial Philips cap remaining.
The photo I posted above is the state before replacement (taken in order to remember where all the cables go).
Unfortunately I have followed the advice given yesterday and removed the Allen screws which hold the Laser assembly. I put them back and the player reads CDs (and skips as it did before). Anyway it seems that I am at the foot of a steep learning curve again. And I will need to switch on that scope 🙂
So next step will be to check according to what you suggest. I am a bit short on time right now so this might take a while.
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I was looking at these:
You have to look at the RF, its quality and amplitude. Should be around 1.2 volts peak/peak and look this with regard to quality:
You have to look at the RF, its quality and amplitude. Should be around 1.2 volts peak/peak and look this with regard to quality: