I went to IFA fair in Berlin, spending a day in the area reserved for suppliers. Only one displayed boomboxes. None displayed OEM CD/DVD mechanisms.
One offered contact to some nonamers in China.
The CEO of an european company which does OEM for many High End CD told me, that Sanyo is the only brand left, that produces mechs for audio.
Sony, Philips (now Gibson) left the market. But Sanyo was aquired by Panasonic in 2011.
No hint on Panasonic Industrial that CD/DVD mechanismss are still produced for OEM.
So we are in the same situation as the record industry in the late eighties - which ended in producing sought high quality gear!
Patents for the CD have expired - so why not producing our own
high quality mechs? If a prototy can be built, crowdfunding could be the next step for mass production.
Some parts like laser diodes can be still obtained, there are some experts
in this forum who know a lot about laser assemblies, many broken assemblies can be scrutinized and compared and maybe even some retired developers can be found to give advice.
There is 3D printing for prototyping, the tough part will be the optical system, coils and proper aligning.
My dream would be a "classical" three beam laser which could be placed on different "baseplates" and therefor mechanically (and electronically) aligned to fit into older traverse mechanisms
as well as using it for actual DIY projects.
So the High End classic from the eighties can be revived (But I assume many of them are still running) or a diy player can be built from scratch.
Another "dream" would be swappable laser diodes thus they are the only aging part. (as far as I know, individual alignment is needed)
Brushless motors for durability are another must.
For the option of replacing old lasers:
Sony was a major supplier of RF amplifiers and servo controllers,
about three generations of IC´s for RF amplification / servo Control / decoding were used roughly within the first ten years of production.
Later decoding and servo control was combined on one IC.
As for today, I have no idea, which decoders and servos are obtainable and can will be produced in the future.
Thread opened, any propositions?
One offered contact to some nonamers in China.
The CEO of an european company which does OEM for many High End CD told me, that Sanyo is the only brand left, that produces mechs for audio.
Sony, Philips (now Gibson) left the market. But Sanyo was aquired by Panasonic in 2011.
No hint on Panasonic Industrial that CD/DVD mechanismss are still produced for OEM.
So we are in the same situation as the record industry in the late eighties - which ended in producing sought high quality gear!
Patents for the CD have expired - so why not producing our own
high quality mechs? If a prototy can be built, crowdfunding could be the next step for mass production.
Some parts like laser diodes can be still obtained, there are some experts
in this forum who know a lot about laser assemblies, many broken assemblies can be scrutinized and compared and maybe even some retired developers can be found to give advice.
There is 3D printing for prototyping, the tough part will be the optical system, coils and proper aligning.
My dream would be a "classical" three beam laser which could be placed on different "baseplates" and therefor mechanically (and electronically) aligned to fit into older traverse mechanisms
as well as using it for actual DIY projects.
So the High End classic from the eighties can be revived (But I assume many of them are still running) or a diy player can be built from scratch.
Another "dream" would be swappable laser diodes thus they are the only aging part. (as far as I know, individual alignment is needed)
Brushless motors for durability are another must.
For the option of replacing old lasers:
Sony was a major supplier of RF amplifiers and servo controllers,
about three generations of IC´s for RF amplification / servo Control / decoding were used roughly within the first ten years of production.
Later decoding and servo control was combined on one IC.
As for today, I have no idea, which decoders and servos are obtainable and can will be produced in the future.
Thread opened, any propositions?
Maybe because it is the absolute end of the optical media era ? Haven't touched a CD for at least 3 years....and then, who still buys them ? It won't be a surprise that we will read that the media themselves are not produced anymore one of these days. I don't think nostalgia as with record players will let CD survive as it can already be seen that music is distributed on USB keys. The trend seems to be very high resolution files which CD players don't play. Playing FLAC or WAV on a nice SSD equipped media player is more convenient and better sounding in many cases. True, manufacturers are not very keen on audio anymore so many new audio devices have something to desire for. Some are nicely engineered devices that offer more possibilities than CD players and take a lot less space in the house. No need to adjust mechanics and to find obsolete laser units anymore 
The special RF amplification/servo control/decoding chips are not produced by the big names anymore as they left the market or they are about to leave the market. if you insist on going on with CD then you will have to look into the chinese manufacturers that still produce CD stuff. I am not sure if quality is of prime importance for them. So even if you can make a mech and a laser (which will cost many hours), then the hunt for chips will begin. It probably is way easier to find a good old CDM4 player and find an extra mech for it in case it breaks down.
It will probably cost way less time and money to convert all your CD's to (lossless) FLAC files and play those on a low jitter audio player likely with better sound quality.
You never know what can happen though :
http://www.bloomberg.com/news/videos/2015-09-01/the-last-audio-cassette-factory
The special RF amplification/servo control/decoding chips are not produced by the big names anymore as they left the market or they are about to leave the market. if you insist on going on with CD then you will have to look into the chinese manufacturers that still produce CD stuff. I am not sure if quality is of prime importance for them. So even if you can make a mech and a laser (which will cost many hours), then the hunt for chips will begin. It probably is way easier to find a good old CDM4 player and find an extra mech for it in case it breaks down.
It will probably cost way less time and money to convert all your CD's to (lossless) FLAC files and play those on a low jitter audio player likely with better sound quality.
You never know what can happen though :
http://www.bloomberg.com/news/videos/2015-09-01/the-last-audio-cassette-factory
Last edited:
Hi Salar,
I agree completely. I do think it is worthwhile to create a flexible mechanism that will accept various laser assemblies. One thing I can guarantee is that with better transverse assemblies, you can make a vast improvement in the sound quality. So the better CD player depends on the head and transverse assy's. Chip sets for computer DVD / CD ROMs are available. But if you look back at the beginning, it was all done with op amps and SSI and MSI digital chips (small and medium complexity chips). Certainly a PIC can be programmed to process the transverse assy commands, plus run the digital side (or use two chips). Microchip has DSP chips and they can be reprogrammed while installed on the PCB. So we have I-V conversion and amplification to give us an RF waveform. The decoding engine can be a currently manufactured chip, or a DSP running a program - along with maybe a little more data memory for error correction. The D/A converter and audio path can be modular so you can have whatever decoding engine you want, coupled with tube, discrete or IC technologies. When I say tube stage, I mean more than a single token tube.
Then there is the chassis. Proper decoupling can be given attention, and it can become a beautiful work of art. So a new model is merely an alternate case and maybe some code touch-ups. Integration to home automation, or common control from the system can be retrofitted once the more popular formats are figured out.
A basic device that is extremely good with a set of options as the owner decides on, or wants to add later. We have experts in each field to call on for support. Using something like Microchip micro-controllers will free us from availability worries.
I don't know about replaceable laser diodes, but I would like to see that. Sanyo made some really good heads, they fell down by not making a good transverse mechanism. The heads didn't have a bearing surface and those wore out quickly. That, we have sorted out.
-Chris
I agree completely. I do think it is worthwhile to create a flexible mechanism that will accept various laser assemblies. One thing I can guarantee is that with better transverse assemblies, you can make a vast improvement in the sound quality. So the better CD player depends on the head and transverse assy's. Chip sets for computer DVD / CD ROMs are available. But if you look back at the beginning, it was all done with op amps and SSI and MSI digital chips (small and medium complexity chips). Certainly a PIC can be programmed to process the transverse assy commands, plus run the digital side (or use two chips). Microchip has DSP chips and they can be reprogrammed while installed on the PCB. So we have I-V conversion and amplification to give us an RF waveform. The decoding engine can be a currently manufactured chip, or a DSP running a program - along with maybe a little more data memory for error correction. The D/A converter and audio path can be modular so you can have whatever decoding engine you want, coupled with tube, discrete or IC technologies. When I say tube stage, I mean more than a single token tube.
Then there is the chassis. Proper decoupling can be given attention, and it can become a beautiful work of art. So a new model is merely an alternate case and maybe some code touch-ups. Integration to home automation, or common control from the system can be retrofitted once the more popular formats are figured out.
A basic device that is extremely good with a set of options as the owner decides on, or wants to add later. We have experts in each field to call on for support. Using something like Microchip micro-controllers will free us from availability worries.
I don't know about replaceable laser diodes, but I would like to see that. Sanyo made some really good heads, they fell down by not making a good transverse mechanism. The heads didn't have a bearing surface and those wore out quickly. That, we have sorted out.
-Chris
@jean-paul
I would rather prefer to stay on topic and not start a general if a development is useful.
But your link to the cassette factory is encouraging.
At least the funeral for the CD is luxurious, this is actually sold for $17.500!
C.E.C. TL 0 CD transport | Stereophile.com
Pressed CD´s will probably last until 2080. Would be nice to have a mechanism that still works then.
-Goal is to develop a durable CD-Mechanism which is at least on par with
first generation mechanisms. This is not nostalgia. This mechs were top notch
with glass lenses and completely serviceable and adjustable laser heads.
Also brushless motors were widely used, gears was solid without play.
-Goal is to gather people here who might be willing to contribute their skills.
Some people / developers from the beginnings are welcome
-Goal is to find the suppliers needed for this mechanism.
-Goal is to develop a prototype with mechanics and servo systems which leads to
crowdfunding for mass - production.
I can provide the mechanical stuff like designing and milling the laser head and mechanism. In electronics I am an idiot. There is better people in the forum to deal with electronics.
@anatech.
No,I meant that it would be nice, if this newly developed laser head only could fit into old players (using mechanical / electronical adaptation)
But designing a new mechanism is the main goal. I completely agree to your post.
This is how the task was done in first generation consumer players:
SONY CDP-101 DE Service Manual free download, schematics, eeprom, repair info for electronics
PHILIPS CD100-00-05 SM Service Manual free download, schematics, eeprom, repair info for electronics
I would rather prefer to stay on topic and not start a general if a development is useful.
But your link to the cassette factory is encouraging.
At least the funeral for the CD is luxurious, this is actually sold for $17.500!
C.E.C. TL 0 CD transport | Stereophile.com
Pressed CD´s will probably last until 2080. Would be nice to have a mechanism that still works then.
-Goal is to develop a durable CD-Mechanism which is at least on par with
first generation mechanisms. This is not nostalgia. This mechs were top notch
with glass lenses and completely serviceable and adjustable laser heads.
Also brushless motors were widely used, gears was solid without play.
-Goal is to gather people here who might be willing to contribute their skills.
Some people / developers from the beginnings are welcome
-Goal is to find the suppliers needed for this mechanism.
-Goal is to develop a prototype with mechanics and servo systems which leads to
crowdfunding for mass - production.
I can provide the mechanical stuff like designing and milling the laser head and mechanism. In electronics I am an idiot. There is better people in the forum to deal with electronics.
@anatech.
No,I meant that it would be nice, if this newly developed laser head only could fit into old players (using mechanical / electronical adaptation)
But designing a new mechanism is the main goal. I completely agree to your post.
This is how the task was done in first generation consumer players:
SONY CDP-101 DE Service Manual free download, schematics, eeprom, repair info for electronics
PHILIPS CD100-00-05 SM Service Manual free download, schematics, eeprom, repair info for electronics
Hi Salar,
I am really interested to see where we can take this.
The combination of a good transport and good electronics will be the first time they were put together. Old machines that worked had large, beautiful eye patterns. Today's chip sets can pull material from almost closed eye patterns. Imagine what they can do with a clear, open eye pattern. Stick this together with modern logic control and the D/A converters available today and you have something pretty special. Even the op amps are better these days!
I'll help where I can Salar.
-Chris
I am really interested to see where we can take this.
The combination of a good transport and good electronics will be the first time they were put together. Old machines that worked had large, beautiful eye patterns. Today's chip sets can pull material from almost closed eye patterns. Imagine what they can do with a clear, open eye pattern. Stick this together with modern logic control and the D/A converters available today and you have something pretty special. Even the op amps are better these days!
I'll help where I can Salar.
-Chris
Hi Chris!
That sounds great, lets start!
First shot, laser diodes.
http://rohmfs.rohm.com/en/products/databook/datasheet/opto/laser_diode/multi_beam/all_ld.pdf
Any other manufacturers? And where to look for photodiodes?
All the best, Salar
That sounds great, lets start!
First shot, laser diodes.
http://rohmfs.rohm.com/en/products/databook/datasheet/opto/laser_diode/multi_beam/all_ld.pdf
Any other manufacturers? And where to look for photodiodes?
All the best, Salar
Hi Salar,
You will notice that there is an extra diode in each. It is used as a monitor for laser output control.
Why not try to identify a laser head first, then figure out what laser diode it uses and go that way. Even the horrible HOP-M3 might work well in a different transverse mechanism. Note that that head is as cheap as you can probably get. The entire body is cheap plastic, so it will probably change dimensions in the longer run.
The Sanyo SF-90 line of heads is in a cast metal body, plus it usually has a nice eye pattern. This would be my suggested course to take. The signal is strong enough as to not need the I-V converters on the head. You could mount that stuff in the sled if you felt that strongly about it. Anyway, I think the optical path in the SF-90 is the best of everything that might be available. Once you have stable optics, you can worry about changing the laser diodes.
-Chris
You will notice that there is an extra diode in each. It is used as a monitor for laser output control.
Why not try to identify a laser head first, then figure out what laser diode it uses and go that way. Even the horrible HOP-M3 might work well in a different transverse mechanism. Note that that head is as cheap as you can probably get. The entire body is cheap plastic, so it will probably change dimensions in the longer run.
The Sanyo SF-90 line of heads is in a cast metal body, plus it usually has a nice eye pattern. This would be my suggested course to take. The signal is strong enough as to not need the I-V converters on the head. You could mount that stuff in the sled if you felt that strongly about it. Anyway, I think the optical path in the SF-90 is the best of everything that might be available. Once you have stable optics, you can worry about changing the laser diodes.
-Chris
OK, I adapt. Is the choice for a laser diode also depending on what kind of mechanism will be used ? So the swingarm type, the later cheap "carriage" type mechs or the "floating" mechanism. I liked the Philips CDM swingarms a lot (no problem with gap of 4 mm) but the Pioneer magnetic floating mechs were faster and had no friction as the laser unit was floating in the air in a magnetic field ("Magnetschlitten "). Particularly the mech as used in Pioneer PD-8500 was a very fast and good one. No need to lubricate etc.
Pioneer PD-8500
Maybe the project will run more fluid if design goals are stated ? Choice of laser diode, choice of type of mechanism, direct drive or belt driven, choice of spindle motor (brushless 4 phase I take ?) and of course check availability of those parts first. If you like the CDM type swingarms you could take a cast aluminium chassis of an old CDM1 and design according the same dimensions and find a suitable laser and spindle motor for that. It will make it possible to fit the mechanism in older Philips/Marantz etc. CD players. The cast aluminum chassis is shaped not very complicated.
Pioneer PD-8500
Maybe the project will run more fluid if design goals are stated ? Choice of laser diode, choice of type of mechanism, direct drive or belt driven, choice of spindle motor (brushless 4 phase I take ?) and of course check availability of those parts first. If you like the CDM type swingarms you could take a cast aluminium chassis of an old CDM1 and design according the same dimensions and find a suitable laser and spindle motor for that. It will make it possible to fit the mechanism in older Philips/Marantz etc. CD players. The cast aluminum chassis is shaped not very complicated.
Last edited:
Hi jean-paul,
The Sony KSS-151A mechanism was much better, faster due to lower mass. The Sony heads seemed to last just fine. Check the Tascam CD-401. The upper Denon machines used that head as well.
-Chris
Have you seen the procedure to align the laser on those??? It is a nightmare that was properly a factory only setup. We had problems with the flexible PCB from the head.
What was belt driven, the feed motor?
The lens used to fall out of those, cheap crappy heads. I have one spare for a Denon machine.
The Sony KSS-151A mechanism was much better, faster due to lower mass. The Sony heads seemed to last just fine. Check the Tascam CD-401. The upper Denon machines used that head as well.
-Chris
I know them better than I want to admit They were amongst the first though and I think they were too complex for commercial gear. They were costly to produce too. Philips just wanted to play safe with this then new technology. Personally I like them best as no other mech tolerates disk errors more than they do.
- Belt driven spindle motor: just like C.E.C and others do. It is a possibility.
- Regarding the PD-8500 mech: yes the lens was crappy but the mech wasn't. The laser is only a part of the mechanism. There is no need to replicate a technical problem. Make it better. Think of a linear mech with a good laser if you like. Fast, no friction etc.
I think we need to think more concept like and not repair man like. If you make something new you better go for the best isn't it ? Repair men only see defective gear. If they see a percentage of a large sold number they tend to think the device is crappy. You don't see much RMA gear when there are only sold 100 of them or it must be a real bad device. I see many CDM4's still doing what they have to do: play disks flawlessly.
They were amongst the first though and I think they were too complex for commercial gear. They were costly to produce too. Philips just wanted to play safe with this then new technology. Personally I like them best as no other mech tolerates disk errors more than they do. - Belt driven spindle motor: just like C.E.C and others do. It is a possibility.
- Regarding the PD-8500 mech: yes the lens was crappy but the mech wasn't. The laser is only a part of the mechanism. There is no need to replicate a technical problem. Make it better. Think of a linear mech with a good laser if you like. Fast, no friction etc.
I think we need to think more concept like and not repair man like. If you make something new you better go for the best isn't it ? Repair men only see defective gear. If they see a percentage of a large sold number they tend to think the device is crappy. You don't see much RMA gear when there are only sold 100 of them or it must be a real bad device. I see many CDM4's still doing what they have to do: play disks flawlessly.
Last edited:
Hi jean-paul,
I'll disagree with you a little.
As a repair guy, and thinking like one, I feel we can avoid the most common problems. My exposure included Recording Studio, Radio Station, Practice Studio, high end equipment and mid-fi equipment. Having seen what works and what doesn't affords me a pretty good idea how to stay out of trouble.
Ah heck, here's why:
The disc motor has to constantly speed up and slow down quickly and precisely. CDs are constant velocity animals that might also be off-center, or the tracks are off-center. Then there is the random button that kills motors faster than anything. The constant acceleration up and down really tears the brushes up - and the sleeve bearings in the top of the motor. Reading the TOC, the CD spins roughly around 500 RPM. Out at the edge on a long CD (70 min + ), the rotational speed is closer to 200 RPM.
What does turn at a constant angular velocity? A turntable. So all these things, stable platter (<---- turntable term), damping rings, belt drive. Those are all associated with turntables. The CD is a completely different animal and has it's own best way of operating. Don't fight the physics.
For the same reason, any attempt at a so-called "Stable platter" increase the rotational moment and makes the wear forces much greater. Stabilizing rings that you put on CDs do the same thing. The lightest rotating mass will have fewer errors and track much better. Never mind about being more reliable.
I did warranty for many high end and high quality professional equipment. I saw the early failures and developed some of the fixes for the problems. I was trained on CD players from their introduction and on forward. CDs became a large portion of our work load, and I was known for being pretty good with them. I might have some good experiences to share if you would only take the time to think about what I have said. If you ask for more information, I will try to get it for you. I am an audio service technician, not a TV or VCR tech. There is a difference between them (on average, some TV techs are excellent with audio too). I suck at TVs and VCRs.
-Chris
I'll disagree with you a little.
As a repair guy, and thinking like one, I feel we can avoid the most common problems. My exposure included Recording Studio, Radio Station, Practice Studio, high end equipment and mid-fi equipment. Having seen what works and what doesn't affords me a pretty good idea how to stay out of trouble.
No offense to you, but this is the most stupid drive system that has ever been conceived! What drooling idiot came up with this? Now, ask me why ....
Ah heck, here's why:
The disc motor has to constantly speed up and slow down quickly and precisely. CDs are constant velocity animals that might also be off-center, or the tracks are off-center. Then there is the random button that kills motors faster than anything. The constant acceleration up and down really tears the brushes up - and the sleeve bearings in the top of the motor. Reading the TOC, the CD spins roughly around 500 RPM. Out at the edge on a long CD (70 min + ), the rotational speed is closer to 200 RPM.
What does turn at a constant angular velocity? A turntable. So all these things, stable platter (<---- turntable term), damping rings, belt drive. Those are all associated with turntables. The CD is a completely different animal and has it's own best way of operating. Don't fight the physics.
For the same reason, any attempt at a so-called "Stable platter" increase the rotational moment and makes the wear forces much greater. Stabilizing rings that you put on CDs do the same thing. The lightest rotating mass will have fewer errors and track much better. Never mind about being more reliable.
Sony KSS-151A head / sled combination. Like Technics CD Players, it uses a linear magnetic motor. But, it still runs on a rod with sleeve bearings and a wheel(s). This works well and is extremely reliable. Never mind quiet and fast. Pioneer, but done much better. The Sony is also a very low mass design, which is very good for all kinds of reasons. Gear drive is the next best method, but not with a worm gear (like Denon, although they fixed some of those problems).
But I have fixed many. They use the same motor as most other machines and it wears out in about the same time period. They also have / had a problem with the disc table sliding down the shaft.
I did warranty for many high end and high quality professional equipment. I saw the early failures and developed some of the fixes for the problems. I was trained on CD players from their introduction and on forward. CDs became a large portion of our work load, and I was known for being pretty good with them. I might have some good experiences to share if you would only take the time to think about what I have said. If you ask for more information, I will try to get it for you. I am an audio service technician, not a TV or VCR tech. There is a difference between them (on average, some TV techs are excellent with audio too). I suck at TVs and VCRs.
-Chris
Of course you have fixed many. I did too. They are decades old and so are the common problems we encountered ! You could see positive sides of their design and rebuild it with todays parts. It starts with the principle design what mech you want to build. What I mean to say is that some failures can be eliminated by design.
Hi Chris!
Sanyo SF-90 is not an option in the moment.
The mechanism as well as the laser should be built from scratch to become
independent from the industry.
Using an existing laser is only an option when sourcing the parts for the laser
becomes impossible.
About the design:
No belts, brushless motors only. Also excessive mass should be avoided.
I own a KSS-151 mech, (German Term "Magnetschlitten") in english it is simply called a linear drive as far as I know.
Looks like the laser is dying, I only measure around 0.8V in the eyepattern, should be 1.2. Still very clean
If it is no problem in implementing a linear drive I would second that.
We have to deal with coils anyway and a far as I know, there is a large community on the net concerned with linear drives especially for milling and 3 D printing.
Again, the idea is to go from prototype to crowdfunding. Many people
remember these drives it could be selling argument.
Here is a link to the CDP-502 which uses this drive. But there was many Sonys and Accuphases using this:
SONY CDP-502ES2 552ESD2 620ES2 650ESD2 SM Service Manual free download, schematics, eeprom, repair info for electronics
I will start making some phone calls to German laser companies to
check out out if related technologies are used. I already envision myself explaining to many persons on the phone that it is really about redesigning
even though one can get a mech for 3 bucks...
Sanyo SF-90 is not an option in the moment.
The mechanism as well as the laser should be built from scratch to become
independent from the industry.
Using an existing laser is only an option when sourcing the parts for the laser
becomes impossible.
About the design:
No belts, brushless motors only. Also excessive mass should be avoided.
I own a KSS-151 mech, (German Term "Magnetschlitten") in english it is simply called a linear drive as far as I know.
Looks like the laser is dying, I only measure around 0.8V in the eyepattern, should be 1.2. Still very clean
If it is no problem in implementing a linear drive I would second that.
We have to deal with coils anyway and a far as I know, there is a large community on the net concerned with linear drives especially for milling and 3 D printing.
Again, the idea is to go from prototype to crowdfunding. Many people
remember these drives it could be selling argument.
Here is a link to the CDP-502 which uses this drive. But there was many Sonys and Accuphases using this:
SONY CDP-502ES2 552ESD2 620ES2 650ESD2 SM Service Manual free download, schematics, eeprom, repair info for electronics
I will start making some phone calls to German laser companies to
check out out if related technologies are used. I already envision myself explaining to many persons on the phone that it is really about redesigning
even though one can get a mech for 3 bucks...
Hi jean-paul,
I'll agree with you there. I'll just say that problems can be avoided best by looking at what was a problem back in history and avoiding it. So there is value in studying historical records.
Hi Salar,
If you want to build your own head, then find an OMS-7 laser head and take it apart. You will clearly see the optical path and how it was implemented. You will also see the required adjustment points, then be able to set up a method of aligning the head. The KSS-123A was the next big use head. Its problem was that the upper lens assy would stick on the post it rides on. I have fixed a few by taking it apart and cleaning that post off. An extremely light application of light oil seems to work well after cleaning.
Why not use a commercial head to start with and to vet the rest of the machine? You may find that you can use any number of alternate heads and that rolling your own might cost too much.
Those are my only concerns.
-Chris
I'll agree with you there. I'll just say that problems can be avoided best by looking at what was a problem back in history and avoiding it. So there is value in studying historical records.
Hi Salar,
If you want to build your own head, then find an OMS-7 laser head and take it apart. You will clearly see the optical path and how it was implemented. You will also see the required adjustment points, then be able to set up a method of aligning the head. The KSS-123A was the next big use head. Its problem was that the upper lens assy would stick on the post it rides on. I have fixed a few by taking it apart and cleaning that post off. An extremely light application of light oil seems to work well after cleaning.
Using a junk head made of plastic. It might be useful as a model for a reduced mass head, along with the laser diode it uses.
Yup, that's what we called it.
Careful there. This might be just a fad for a short term. But I do wish you good luck with the attempt.
Why not use a commercial head to start with and to vet the rest of the machine? You may find that you can use any number of alternate heads and that rolling your own might cost too much.
Those are my only concerns.
-Chris
Hi Chris!
Happy to have an OMS-7 laser as well as a KSS-123. But I do not know, if the oms-7 head is still working, have to check this first. Which company was the OMS-7 laser? C.E.C? According to the DAC/Tansport list, name is HLPL 030020 / CA80255A. Maybe the same as OHP-32 used in Toshiba Players,
wich I also own...
All the best,
Salar
Hi Salar,
You could drop the plastic cover to see what it involves without causing any first order damage. Obviously you are opening a clean environment in miniature. I did that with a dead head years ago and recall that I was amazed by the way it was constructed and adjusted. Given the extremely high quality eye patterns these heads deliver, I will assume that there were adjustments they made that are not possible from anyone else. I have seen this head in an old Alpage vertical loading CD player, and the Nakamichi OMS-5 / 7 machines. It looks as if someone designed the optical path in a laser lab, then just miniaturized that setup. I think it was all glass for any optical components, milled aluminum for the rest except for the cover (plastic) and the PCB.
Once you see the inside of this head, you might reconsider making your own. Then again, the road map might make the job easier too. Examining that one might make identifying the different parts in the KSS-123A easier, then on from there.
OEM for that head? I don't know, but it feels like something NEC might make. I would have to say that NEC is probably the highest quality OEM there ever was.
-Chris
You could drop the plastic cover to see what it involves without causing any first order damage. Obviously you are opening a clean environment in miniature. I did that with a dead head years ago and recall that I was amazed by the way it was constructed and adjusted. Given the extremely high quality eye patterns these heads deliver, I will assume that there were adjustments they made that are not possible from anyone else. I have seen this head in an old Alpage vertical loading CD player, and the Nakamichi OMS-5 / 7 machines. It looks as if someone designed the optical path in a laser lab, then just miniaturized that setup. I think it was all glass for any optical components, milled aluminum for the rest except for the cover (plastic) and the PCB.
Once you see the inside of this head, you might reconsider making your own. Then again, the road map might make the job easier too. Examining that one might make identifying the different parts in the KSS-123A easier, then on from there.
OEM for that head? I don't know, but it feels like something NEC might make. I would have to say that NEC is probably the highest quality OEM there ever was.
-Chris
Hi Salar,
What an idiot! I hate stupid people who don't think things through.
The short on this one is just the other side of a notch in the edge of the PCB. The original is a clip, but there are three terminals with leads that solder right on. If you were to short the terminals with some wire before you take the wires off you'll be fine. The wires are: ground, laser, monitor diode. You'll see this easily.
As far as the belt drive for feeding the transverse back and forth is concerned, it was a very bad design. I would love an alternate if you think of anything. As far as I'm concerned, that is the one weak spot in the entire player. The only electrical thing I'm not happy about are the TDA1540 DACs. I think they are 14 bit, but they managed to make it sound much better than most 16 bit machines. At least they were a dual DAC. The filter is in a black box along the rear of the chassis near the RCA output terminals (no shock there I guess). They managed to make it pretty quiet, and I have no doubt that this is the secret as to why the CD player sounds as good as it does. It would be interesting to run a frequency sweep to get the transfer function. They might have done something interesting there.
What the PCBs, especially the power supply and the remote jack on the rear. They have used the glue that corrodes copper, so there is a lot of that stuff to remove. They also used it on the foil side of the servo PCB I think. Just look for that yellow - brown - dark brown deposits. The dark brown is conductive. You should be able to measure resistance using a normal ohmmeter. The darker yellow is the corrosive stage. Scrape it all out.
I have repaired all kinds of bizarre problems with these machines, through the entire OMS lineup. That yellow glue was behind every strange problem I ever had. As long as the copper is there on the PCB and the components have leads left, removing the glue will solve most of your issues - and future ones as well.
I hope that helps, Chris
What an idiot! I hate stupid people who don't think things through.
The short on this one is just the other side of a notch in the edge of the PCB. The original is a clip, but there are three terminals with leads that solder right on. If you were to short the terminals with some wire before you take the wires off you'll be fine. The wires are: ground, laser, monitor diode. You'll see this easily.
As far as the belt drive for feeding the transverse back and forth is concerned, it was a very bad design. I would love an alternate if you think of anything. As far as I'm concerned, that is the one weak spot in the entire player. The only electrical thing I'm not happy about are the TDA1540 DACs. I think they are 14 bit, but they managed to make it sound much better than most 16 bit machines. At least they were a dual DAC. The filter is in a black box along the rear of the chassis near the RCA output terminals (no shock there I guess). They managed to make it pretty quiet, and I have no doubt that this is the secret as to why the CD player sounds as good as it does. It would be interesting to run a frequency sweep to get the transfer function. They might have done something interesting there.
What the PCBs, especially the power supply and the remote jack on the rear. They have used the glue that corrodes copper, so there is a lot of that stuff to remove. They also used it on the foil side of the servo PCB I think. Just look for that yellow - brown - dark brown deposits. The dark brown is conductive. You should be able to measure resistance using a normal ohmmeter. The darker yellow is the corrosive stage. Scrape it all out.
I have repaired all kinds of bizarre problems with these machines, through the entire OMS lineup. That yellow glue was behind every strange problem I ever had. As long as the copper is there on the PCB and the components have leads left, removing the glue will solve most of your issues - and future ones as well.
I hope that helps, Chris
Last edited:
The belt driving the laser is still a problem though, it will wear out over the years. Got some replacement belts on the shelf. Somebody selled them on ebay and maybe he still does.
BTW, a syblingl to the OMS-7:
Kyocera DA-910 on thevintageknob.org
But it looks like the D/A section is not shielded...
BTW, a syblingl to the OMS-7:
Kyocera DA-910 on thevintageknob.org
But it looks like the D/A section is not shielded...