Micromega T-Drive and 912/04 loader and CDM9 - diyAudio
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Old 9th January 2009, 03:42 AM   #1
PhilHJ is offline PhilHJ  United Kingdom
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Default Micromega T-Drive and 912/04 loader and CDM9

I couldnt find anything here about the T-Drive and the 912/04 loader so I thought I would gather together the information which I hunted down from all over the web, but mainly this forum. Many thanks for your great information and the obvious kindness and generosity of many experts here.

My T-Drive is from 1993 according to the board dates.
The transport is as has been said above, marked 912/04, which is a high quality transport made by Philips, probably by their subsidiary Daisy Laser who made the CDM9 laser mechanism. There is a Philips part number following the 912/04 number on the label.

http://www.daisy-laser.com/products/products_map.htm

The laser mechanism is marked CDM9/65 on the label, followed by another Philips part number. This is a variant of the type called CDM9Pro - threads also mention CDM9/60 on some CDM9Pro type assemblies. I dont know the difference.

The CDM9Pro is described as different from the standard CDM9 through using a brushless spindle drive for the CD rotation, as opposed to brushed (thereby reducing motor induced electrical noise and eliminating brush failure). Other possible differences are the use of metal instead of plastic CD spindle, and the use of a superior metal frame. There is some mention of differences in glass / plastic lenses, but most sources agree that CDM9s and CDM9Pros use identical laser / lens assemblies and that plastic was only introduced with the CDM12. The standard CDM9 is CDM9/44.

The CDM9 is a high quality radial swinging arm design which gives extremely high audio accuracy at the expense of slow access speeds (changing tracks takes a long time on these drives). Subsequently the designs changed to linear three diode assemblies allowing multiple simultaneous reads, and paving the way to faster access and faster reading for non audio applications.

Audio Quality

These mechanisms are the peak of the radial arm series of designs and were used only on the highest end machines of their day. Later mechanisms use different technology, some people like them, but many regard the CDM9 and some of the other top end CDM products as unsurpassed.

I use T-Drive (Mark 1) -> AES link -> T-Dac -> Transparent Link cables -> Copland CDA28 -> Transparent speaker cables -> B&W CDM1SE and ACI Titan kit sub.

I bought this equipment in 1998 except the Titan which I built in 2001. After auditioning numerous CDs I complained they all sounded CDish and unlike the sound I used to get from my Rega Planar 2 / Lux amp / Tangent TM1 speakers.

Thats when the salesman said, ah I thought you were here to buy hi-fi, why didnt you say you wanted music. He produced the T-Drive and T-Dac from the second hand pile and put the Transparent cables on.

I have to say the effect was unbelievable. Up until then I had been listening to speakers. At that point (in their optimised listening room I accept) the speakers simply disappeared and became a soundscape of instruments and voices.

I find it amazing demoing it to people. For 95% of people the system is a waste of money, they simply cant hear it. For the other 5% they don't want to leave it. And I've given all three of my children a big problem, 2 have already left home, and they miss the system big time. (They'll have to make do with the Marantz stuff I bought them until they can earn it !)

Sorry for the personal narrative - its part of the story, hope you dont mind ;-) The Micromega has had tough family use for 10 years now (and is actually 15 years old). I always leave it on, using the rubric that pulsing equipment is generally worse for the components than steady state, and anyway who knows how long it really takes to stabilise when you switch it on. (The system gave me headaches for the first few days of listening).

Info on the CDM family from a Marantz perspective:

http://www.marantzphilips.nl/index.a...strP age=Info

The also claim to have service instructions here;
http://www.marantzphilips.nl/philips_service_manuals/
but I would try diyaudio first.

Repairs:
[Go to DIYAudio and learn about about how to do this sort of stuff. Use static protection as static can kill the laser or other circuitry. Be very gentle with delicate circuits, connectors, or ribbons / cables. If you arent expert / its worth a lot to you then consider hiring an expert such as http://www.cptacoustics.com/]
[[I dont know him, he is just recommended in a CDM9 thread]]

CDM9 and CDM9Pro mechanisms became unavailable as new spares from Philips about 2007 and are now only available from salvage parts, but there seem to be plenty of the CDM9s around. They were used almost exclusively in high end players so can be recovered from some high end Philips, Rotel, Theta, Marantz, Arcam (5,6) etc. There is a list out there but I cant find it again right now and am not going through every site I visited again ! They were also available for some reason in a couple of Philips CDROMs: CM201 CM206

If the laser fails its possible to use a laser from any CDM9 as they are all the same. The swinging arm and laser assembly can be transferred.

If the machine has difficulty reading TOC or skipping, it may be because the swinging arm is stiff. Many users have had success with removing the ball bearing cover and adding a small drop of suitable lubricant - search the diyaudio threads for details on the right stuff - dont just use anything you may regret it.

If the spindle is damaged some canny users have managed to get one off another mechanism, it may be "superglued" on and need some pressure and a sharp tap to break the glue bond and release the CD spindle from the motor axle. The 9/44 axles is a little smaller than the 9PRO so it can be opened out to fit the 9/65 presumable the reverse is impractical.

The drive tray doesnt drive in and out any more, after sounding graunchy for a while.

This is a common problem with all CDM9 trayloaders. The CDM9 package was shipped with slightly different trayloaders for different companies, but they seem to all have been supplied with the same tray drive gear, and that gear has aged on many players to the extent that the drive teeth break off.

An interaction between aggressive grease and the plastic is often claimed to be the cause. Philips and others manufactured replacements in a different plastic, but the Philips ones recently became unavailable. However there are still Far East made replacements available, just type CDM9 gear into Ebay or a search engine and you should find them.

Some cunning folk have cut the gearteeth from the end of the pulley shaft and got local repair guys to find a gear wheel the right size to glue on the shaft. Other cunning people have wound some soft but durable rubber in place of the gear and use it to drive the tray rack, at least as a short term solution.

My solution, borrowed from a thread, is to add a handle and turn it into a manual tray loader. I unscrewed the metal piece on the front of the tray trapped some elegant fine wire at the left and right ends and screwed the fascia piece back leaving the wire hanging out the front. I removed the broken gear so it doesnt rattle on the tray and disconnected the tray motor connector so it doesnt whir when the CD wants to eject. Now you just press the Disk button and pull the drawer open. Close doesnt need a button press, it recognises it automatically. I love my T-Drive and have no intention of opening it for another repair unnecessarily. Even for the expert every time inside an older bit of equipment is a risk.

The grease is said to dry out and stiffen. If the tray leader struggles to go in and out but still moves then open the unit (four screws underneath and pull the top / sides case away from the floor/front/back). Then clean off visible grease from the sliders. Then apply silicone cleaner (Maplin) and regrease with a small amount of silicone grease (Maplin). Dont use any standard oil based grease, they attract dirt, dry out and stiffen with time.

Acting when the tray becomes sluggish may deter gear failure.

Prices
At the time of writing in Jan 09, a search on Ebay shows gears in the range $20-30. On the complete mechanism GranData http://<br /> http://www.grandata.c...sm-p-4987.html
shows CDM9 at 24, and theres a replacement CDM9Pro on US Ebay at $110, but the threads suggest these are pretty hard to come buy and can be suspect depending on the source.


Further Reading:
The info here was gathered from all over the web, but the single biggest source of amazing expertise is the diyaudio forum where there are people incredibly knowledgeable about the inside of CD players.
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Old 9th January 2009, 08:01 PM   #2
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You don't really hear much about the mk1, the mk2 is far more common using the CDM 12.4. In terms of sound quality the mk2 is the better of the two, but only by a smidge, the construction on the mk1 is fantastic and in terms of sound beats most transports from other people even now.
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