Back From The Brink. A 2nd Lease of Life For My Marantz CD 7.

My Marantz CD 7 is given a second lease of life!
It's now become public knowledge that some sucker is desperately looking for spares to repair his beloved Marantz CD 7.

With all hopes of getting a spare Philips VAM1252 transport mechanism assembly faded, and everyone around me offering either condolences or celebrating my opportunity to up grade(again?), one guy came up with an idea. Why not go DIY? I answered that "I've not done digital before, what happens if we get stuck?" "Then go ahead and spend the money on that CD player upgrade!" he replied.
The inner chassis with moulded compartments for high strength, just like a car's chassis.
Attention to detail, rubber dampers affixed to bottom of PCB for vibrational control.
As I am not prepared to spend RM$30k on a replacement CD player just yet, I took up his offer to go DIY. Along the way, we got another DIYer buddy, who works as a hifi technician for another big brand. So you'll understand both their request to remain anonymous.

The hollowed out transport mechanism. We took it out to perform the rebuild.
Just in case you forgot what's wrong with my Marantz CD 7, the transport seems to not recognise most disc I wish to play. For some reason it failed to read the TOC(Table Of Contents) on the disc. TOC is the no. of tracks and time information to be displayed when played. Some disc will also have album tittle and artist name too, if one's CD player is designed to display those.

Then we spent a weekend opening up and dismantling the Marantz CD 7. Now I know what makes the up the players heft and weight. The double layer full copper coated casing with the internal chassis moulded with compartments just like a car's monocoque chassis and the outer flat cosmetic panels is the answer.

We've found the best way to access the transport mechanism is from the bottom. Once the bottom chassis plate is removed, it will reveal the VAM1252 transport mechanism assembly with the custom Marantz transport control board(none standard as found on original Philips VAM1252) at the very bottom. We start by removing the custom Marantz transport control board, then access to the bottom of the transport mechanism is revealed. We took the transport mechanism out to find the fault. It appears the center spindle of the original transport had self destruct. The center spindle is to hold the disc while the transport bridge clamps down to stabilise the disc before the spindle motor starts to spin the disc to read TOC.

The bottom of the Philips VAM1252, a.k.a. Philips CD Pro. Note the parallel stainless steel guide rails on either side of the laser diode assembly?
Looks very much like this Philips CDM12.4?, which we used as the parts donor for the rebuild.
We searched the www for information on Philips transport options available. I found that the CDM12.4 is a perfect parts donor candidate for a complete transport rebuild, i.e. we'll strip down the VAM 1252, a.k.a. Philips CD Pro and throw away everything inside except the body. We then proceed to transplant all the new parts removed from the CDM12.4 bar the body. How is this possible you ask?
Top: Philips VAM1252, a.k.a. Philips CD Pro. Bottom right: Philips VAM1254, a.k.a. Philips CD Pro 2.

You see, the only thing PRO about the Philips CD PRO is that metal alloy chassis and an extra laser diode assembly guide rail built in parallel for perfect tracking alignment. All other parts like the laser diode assembly and guide rail motor and center spindle motor is identical to the Philips CDM 12.4!
Philips CDM12.4 top view.
Once the transport rebuild was completed, we re assemble the transport mechanism and start testing. During testing, we encountered another problem, the CD player now reads the disc TOC, and proceeds to play as per usual, only to start skipping irregularly after halfway thru reading a disc. It seems that the new transport doesn't quite like to track the outer parts of a disc. CD players normally reads from the center(TOC, then track 1) towards the outer rim(last track) of the disc. More research on the www was required. I chanced upon a web site called http://www.lampizator.eu/ authored by maverick DIYer Lukasz Fikus. This man adds enthusiasm and inspire our repair work even more than before. He gives away so much information and actual BS about CD players! Do check out his interesting Lampizator concept if you're DIYer, and have a thang tube out put CD players. If only there are more hifi people like him?
The custom Marantz transport control board. Note the 2 blue coloured capacitors are the replacements done by Mr Oh. These capacitors are the regulator/charge storage for the spindle and laser diode guide rail motors.
Following a lead provided by Lukasz on his web site, it would seem that we're experiencing some trouble with the custom Marantz transport control board. It's apparently a common problem that most center spindle or laser guide rail motor doesn't fail, but more likely that the charge regulator/storage capacitors for the motors on the control board had dried up or leaked over a period of time. But neither of us were quite sure which capacitor to fault. I proceeded to bring the control board to Mr Oh, a reputable hifi and CD player specialist repairman in Kuala Lumpur. With his vast experience in CD player repairs, Mr Oh quickly pointed out the faulty capacitors and proceeded to help me replace them. While I was there, Mr Oh very kindly allowed me to raid his parts bin for what ever I need to fix my Marantz CD 7.
Fitting the custom Marantz transport control board from the bottom of the mechanism.
I went home to re assemble the board on to my CD transport mechanism and started testing again, this time the disc reading was faultless from beginning till end. Success!!!, not quite yet. There was still some scratchy noise with the disc reading. It did not affect the disc play, but there was that noise, coming from the transport during playback. I consult Mr Oh again and he mentioned about:

1) alignment of the laser diode assembly guide rails, they must be strictly parallel. Check!

2) alignment of the center spindle to motor and then bridge clamp height. (this is easier said than done) but we managed after many attempts. Check!
Alignment of the spindle to motor and bridge clamp height. This alignment is most tedious to perform.
3) alignment of the tray and bridge clamp centering. Check!
Bridge clamp motor viewed from below.
With all the alignment in place, we reassemble the transport mechanism assembly again to test and this time, success! We tested disc after disc for 2 days with perfect reading results. Once confirmed, we reassembled the whole CD player again and ready to plug the Marantz in to my system again.
Alignment testing, SACD Hybrid disc which are thicker(just very slightly) than a normal red book only CD.
After 3 weekends that we used to complete the transport mechanism re build and testing, the result was very satisfying. Listening to the newly restored player, I heard the same glorious sound like I used to, no more no less. The Marantz CD 7 lives again!
CDR Testing!
More testing!!!
I wish to thank my two DIYer buddies(whose names I am not allowed to mention) for helping me to re build the transport of my CD 7. A special thanks and appreciation goes to Mr Oh for helping out with his time and effort.
Marantz HDAM output module.
Jewel in the crown! The prized Philips TDA1541S2, made in Taiwan for close tolerance and excellent linearity measurement.
The DAC and out put board. Note the balanced topology.

The copper coated/potted power supply transformer.
The spring loaded suspension mounts, made of teflon.
Other than Lukasz Fikus Lampizator web site, my other www resources includes the following sites:

http://www.marantzphilips.nl/

http://www.daisy-laser.com/

http://www.diyaudio.com/forums/digital-source/

http://www.cgi.ebay.com/

For more info, you may also Google or Yahoo search on Philips CDM12.4 or VAM1252 or Philips CD Pro.