Sony CD player optical pickups

[Mooly]

re situation is to observe by "criminally crappy CDM12" series from Philips. This optical pick up's uses a hologram laser (include integrated foto diode matrix and high frequency pre amplifier stages) instead a simply laser diode. Comes this hologram diode from Sharp, a very large reliability and lifetime are to expect. In all other cases it is not so (particularly by optical pick up as replacement for service except that one for juke boxes and other professional stuff).
Interest to know is, that are the diodes itself as original Sharp part much more expensive than a complete optical pick up for CDM12.4

My own experience of the CDM12.4 has been that it is very reliable. That said there were well documented failings caused by the lubricants used, although these were easily correctable...
The CDM12 series were optically, a simple design, mainly because as you say the laser diode was integrated with the photo array, and this meant that apart from the "turning mirror" or prism and the objective lens no other optics were involved. Pickups that used diffraction gratings were an absolute nightmare to have to adjust when replacing pickups.
However you have to accept it is now well over a 15 year old design... and when I think of all the "good" CDM's that must have been binned beacuse of the lubrication problem

 

[tiefbassuebertr]

My own experience of the CDM12.4 has been that it is very reliable. That said there were well documented failings caused by the lubricants used, although these were easily correctable...
The CDM12 series were optically, a simple design, mainly because as you say the laser diode was integrated with the photo array, and this meant that apart from the "turning mirror" or prism and the objective lens no other optics were involved. Pickups that used diffraction gratings were an absolute nightmare to have to adjust when replacing pickups.
However you have to accept it is now well over a 15 year old design... and when I think of all the "good" CDM's that must have been binned beacuse of the lubrication problem

Until two years ago were also by my own service all the laser units, type No CDM12.4 very reliable. The problems with faulty copies already in new condition only emerged from begin of 2008. This I have forget to mention.

Therefore I have started this treads (should I better say "monolog") to get more informations about the real brand names and trustworthy delivery sources:
1) http://www.diyaudio.com/forums/digi...lt0h30pa-inside-philips-cdm12-vam12-mech.html
about post #2 there are some URLs from China's cndiyclub with certainly interest informations and photos - unfortunately I cannot understand this language
2) http://www.diyaudio.com/forums/digi...ick-up-cd-player-wholesaler-manufacturer.html
3) http://www.diyaudio.com/forums/digi...am1254-cdm12pro-vau1254-cdm12-4-compatib.html

 

[Mooly]

I was lucky and when I ordered and fitted a new CDM12.4/05 in my Micromega the supplied part was a "made in Japan" device.
I couldn't believe it and a few weeks later ordered another for stock... and this was supplied in unmarked white box. I fitted it to a test player and it was virtualy unplayable... very low RF output. The mech and motors were new, you could tell, but the pickup was second hand, dirty etc. I returned it and got a still poor replacement.
In the end managed to source a "Malaysian" produced pickup only which I have as a spare. Fitting new motors etc is easy from any of the other pickups in the range. The grey and black platters are of opposite magnetic polarity too, need swapping.
The soft "blue" nylon gears seem unique to the 12.4 and replacing with the hard white type from CDM12.1 etc cause problems with reading the TOC. Perhaps too much backlash or the ratio is slighly different, but they don't work anyway.

I don't know where these parts suppliers are getting these rubbish quality parts from.

 

[tiefbassuebertr]

I was lucky and when I ordered and fitted a new CDM12.4/05 in my Micromega the supplied part was a "made in Japan" device.
I couldn't believe it and a few weeks later ordered another for stock... and this was supplied in unmarked white box. I fitted it to a test player and it was virtualy unplayable... very low RF output. The mech and motors were new, you could tell, but the pickup was second hand, dirty etc. I returned it and got a still poor replacement.
In the end managed to source a "Malaysian" produced pickup only which I have as a spare. Fitting new motors etc is easy from any of the other pickups in the range. The grey and black platters are of opposite magnetic polarity too, need swapping.
The soft "blue" nylon gears seem unique to the 12.4 and replacing with the hard white type from CDM12.1 etc cause problems with reading the TOC. Perhaps too much backlash or the ratio is slighly different, but they don't work anyway.

I don't know where these parts suppliers are getting these rubbish quality parts from.

If I get packages both without any print or "Made in China", mostly the hologram laserdiode was faulty. If I get packages with "Made in Malaysia", "Made in Taiwan" or "Made in Japan", quality was still good (this was true only for the laser unit, so called "CDM12.4 Head" not for the complete mechanism/transport unit).
So I guess that the production facilities in Taiwan, Malaysia and Japan, was at the same time the former supplier to Philips or part of Philips itself.
The currently CDM12.4 exemplares comes now from China without marking and brand name. Therefore I want to have only the diodes as orig. Sharp part respective the successor brand - Sharp has discontinued all hologram laser diodes as you can read by the correspondence to Sharp - go to post' about
http://www.diyaudio.com/forums/digi...lt0h30pa-inside-philips-cdm12-vam12-mech.html

I even have contact with a supplier of a 800 pc LT0H30PA (LTOH30PA) packaging unit orig. Sharp (see attachement), but he don't send samples and the costs are 67 US $/pc at 800 pieces (arround 36.200 Euro + VAT and shipping - forcast/pay in advance - to make a replace by 800 pc. of cd player). Additional there are not to find a data sheet; datasheet of a similar type you will find there:

http://www.datasheetcatalog.org/datasheet/Sharp/mXqxuqy.pdf (LT0H12M)

http://www.daisy-laser.com/products/CD/mechanisms/VAM1202/gh6c005b3_e.pdf (successor of LTOH30PA, new outline, so called "resin" package instead of TO, used in VAM1201/1202/2202 and many more, but not in VAU1254/CDMpro2LF - there are still TO-versions inside as you can see at the photos)

LT0H30P datasheet and Application Note, Data Sheet, Circuit, PDF, Pinout | Datasheet Archive (only short form data)
http://robot.ee.hacettepe.edu.tr/forum/files/20_laser200510_e.pdf (Overview)

The main question for me is, who is the currently supplier brand for the hologram laser diodes inside in the still (by daisylaser) available CDpro2 (VAU1254) units?


Your mention problems regarded the "blue" nylon gear for the skip/search function and the opposite magnetic polarity by the grey and black platters (motor pulley/turntable) for me are completly unknown. I have heard about this from guy's, that have still replace the whole compact disc mechanic (CDM). But for me this replace procedure was too complex, so I always just moved only the optical pick up itself.

 

[Mooly]

Thanks for the data sheet links...
Nobody to my knowledge that has posted on here has ever got anything from Daisy Laser.
I cracked open a Chinese CDM12.4 a couple of years back and the only markings on the Laser diode were a strange symbol in blue ink... no numbers etc that I can remember.
It would be interesting to try and replace just the diode assembly in a pickup like the CDM12.4 as there is no grating adjustment... they come out cleanly and easily. There must be many "scrap" units around that are faulty because of dirt etc, with perfectly good lasers...

I have even stripped down a CDM 12.4 to fully clean but stopped short at removing the diode
http://www.diyaudio.com/forums/digital-source/118902-stripdown-clean-cdm12-4-a.html