Replacing the draw cog and belt on CDM4/19 e.g. CD42/CD52

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I thought I'd do a brief guide on changing this as a couple of people have asked me about it when I mentioned it in another thread. It's very easy to do and the gear and belt are available on Ebay at the time of writing for about £12GBP. The player shown is a Marantz CD52, but the CD42 is the same and probably the CD32 too.

Step One: Remove the four side screws on the case lid (Philips-drive screws)

Step Two: Remove the T10 Torx screw from rear of case lid

Step Three: Remove lid

Step Four: Fold back disc clamp flap

Step Five: Remove spring from flap
 

Attachments

  • DSCF0008-1024.jpg
    DSCF0008-1024.jpg
    123.2 KB · Views: 652
  • DSCF0009-1024.jpg
    DSCF0009-1024.jpg
    134.2 KB · Views: 604
  • DSCF0010-1024.jpg
    DSCF0010-1024.jpg
    122 KB · Views: 617
  • DSCF0011-1024.jpg
    DSCF0011-1024.jpg
    152 KB · Views: 623
  • DSCF0013-1024.jpg
    DSCF0013-1024.jpg
    139.3 KB · Views: 619
Last edited:
...continued...

Step Six: Remove the 3 torx screws from the front panel

Step Seven: Unclip the front panel from the sides of the main chassis

Step Eight: Remove the torx screw from the underside of the chassis at the headphone socket end

Step Nine: With the player resting on its back, pull the face-plate slightly forward and carefully withdraw the tray. It doesn't need to be forced.

Step Ten: Return the player to its normal upright position

Step Eleven: Remove the old belt and tray/draw cog
 

Attachments

  • DSCF0016-1024.jpg
    DSCF0016-1024.jpg
    139.9 KB · Views: 266
  • DSCF0015-1024.jpg
    DSCF0015-1024.jpg
    123.5 KB · Views: 268
  • DSCF0014-1024.jpg
    DSCF0014-1024.jpg
    130.5 KB · Views: 354
  • DSCF0017-1024.jpg
    DSCF0017-1024.jpg
    144 KB · Views: 307
  • DSCF0018-1024.jpg
    DSCF0018-1024.jpg
    123.1 KB · Views: 372
...final part.

Step Twelve: Check the part against the new one and insert the new cog after placing the belt around it and the motor pulley

Step Thirteen: Clean the lens with pure alcohol and a cotton swab whilst you're in there (if you've never done this before)

Step Fourteen: Reinsert tray, clip the front panel back on and put the lid and all screws back as you found them.

Done!

I hope this is useful.

Simon
 

Attachments

  • DSCF0020-1024.jpg
    DSCF0020-1024.jpg
    110.3 KB · Views: 296
  • DSCF0021-1024.jpg
    DSCF0021-1024.jpg
    139.5 KB · Views: 252
  • DSCF0023-1024.jpg
    DSCF0023-1024.jpg
    106.4 KB · Views: 277
  • DSCF0024-1024.jpg
    DSCF0024-1024.jpg
    117.5 KB · Views: 255
  • DSCF0025-1024.jpg
    DSCF0025-1024.jpg
    151.7 KB · Views: 328
CD-52 laser and focus adj without test discA?

@SimontY, many thanks for documenting the process, its still being used. Pity you do not get royalties, I would have been happy to pitch in.

My story, I have just purchased a dead CD52 for restoration and tweaking.
Quick check showed lots of litter from the broken gear wheel as I expected. I have since bought a replacement wheel and belt from Marcmart in HK on eBay.
Unfortunately I also found that someone had been inside it before me, to the point of removing the main board. Nothing was changed thankfully. However, when this moron put it back together he inserted PCB mounting screws into the holes for the laser and focus trim-pots, tightened them until the trim-pot end stop broke, jamming the screw in the hole. (now I know why 2 cover screws were missing).

I have the service manual which describes the fairly simple adjustment process.
But, do I need to acquire the test CD 5A? Does anyone have experience with laser current adjust and focus offset adjust without the test disc, are there any tricks?

Many thanks in advance....

John
 
Thanks Simon,
Have not tried the adjustments yet, i am stripping it down for a clean and tweak.
I decided to separate the 5 and 10 volt supplies by adding a small 20va toroidal mains transformer for the 5V digital needs and increasing the pre and post regulator filter capacitors along the way. Plan to use separate 78L05 regs for each of the 5 DAC power pins and a 7805 for the rest of the digital chain. Any other 5v can run off the existing supply thats shared with the servo. The 15v analog supplies will just get bigger caps and I have pulled the 5532's to replace with LME49720 but will DC couple the outputs. Then there's the oscillator and and and ..
Cheers
John
 
I found the low jitter vcxo from Vintage Audio Labs in Taiwan to do the reclocking, so thats now on order along with the caps and regulators and stuff. All due to arrive next week.

I have moved the existing fuses from transformer secondary to the primary side now that I will reduce the load on the existing transformer (surprising amount of heat marks on the inside of the top cover). There are pads on the main board for one mains fuse (was jumpered) so regrettably I will drill holes nearby for the second fuse to protect the second transformer.

That unfortunately gives me 240Vac wires running from the left hand side of the box to the vacant realestate on the right hand side. Can't see any way to avoid it.

And I have promised myself, that will be all.
 
Very happy with step 1. Gave it a good listening to then a service/clean/re-grease, re-adjusted laser current and focus after replacing all the power supply electrolytics, with a bit of a squeeze to miss the case work and each other.

the +/-15v smoothing were 100/35 are now 2200/35 FR
the +/- 10v were 1000/16 and 3300/16 are now 6800/16 HE
and 21 of the 47/25 scattered post regulator are now 470/25 ZLJ
the op amps are now LME49720 in sockets.
the bypass caps across the rectifier diodes replaced by snubbers on the secondaries, 100n+780R

Result is a remarkable reduction in noise and hiss and hum, its embarrassing how much because I thought it was pretty good before.

Really annoyed by the errors in the Marantz service manual - so many of the references do not line up with the CD52 that I could almost have cooked it.

Still waiting for the Vlab clock but have got my hands on some REG103/104's plus some LT3032's. Both have very good noise and load transient specs but the 3032's are far too small for my eyes. What was I thinking?
 
Last edited:
Oops, assumed you would know
FR = Panasonic, HE = Nichicon and ZLJ = Rubycon.
All 104C, high current (plus 0.8 or 1.0mm lead diam), long life and are tall, narrow with small pitch which makes them ideal for retrofit with much larger values.
I prefer FR and FC but they get expensive, and personally I think these are better than the Elna caps.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.