Sony MDS-E12 belt replacement

Applicable to models with the MDM7 series MD mechanism, including but not limited to:

  • MDS-E12
  • MDS-E10
  • MDS-JE440/640/JB940
  • MDS-JE470/770
  • MDS-JE480/JE780/JB980
  • MXD-D4
  • Most Sony mini and micro hifi stacks that have MD that support MDLP

The recorder began having issues ejecting discs, such as slow ejects and whirring noises. I was concerned by the weight and heat of the device atop the E12 and moved it to another location. This likely dislodged the old belt and caused the recorder to not eject discs at all.

Rather than risk an improperly-sized belt, I ordered a specific belt from an eBay seller based in Portugal. The belt arrived in reasonable time, so I can recommend this route unless you have a cache of belts already on hand.

Eject belt: 17mm dia x 0.8mm square section (53mm circumference).

Note: eBay seller Linx Audio (UK and worldwide shipping) had some belts specifically made for us of the correct specification, see: Linx Audio (eBay) (17x0.8 belt)

Begin by disconnecting power from the wall. Unfortunately, the power cable on the E12 is hard-wired. Do not get lazy here - shorting a device can kill.

The MDS-E12 has 7 screws holding the top panel in place - 3 on top, and 2 on the left and right sides. If the rackmount ears are installed, they should not need to be removed. The top lifts up without much difficulty.

Remove the 4 brass screws surrounding the drive mechanism. There are 2 ribbon cables at the rear of the drive. These are not the most delicate ribbon cables ever, but still treat them with care and wiggle them out slowly.

Use this opportunity to remove the brass screws and place them aside. Also remove the 3 screws on the metal shroud - 2 on one side, 1 on the other.

With the shroud removed, be very careful of the write head on top of the mechanism - touch this and the recorder becomes a player forever.

This is tricky, so don't apply any pressure to anything that doesn't want to move. Part of the mechanism does lift up from the rear, and from there part of the eject mechanism should loosen up.

An experienced technician may need to reconnect the mechanism, power on the recorder and then press the eject button. From there, apply the eject force from the rear. Of course, exercise extreme caution.

If done carefully, applying firm pressure to the white plastic slider at the rear of the drive can get the disc out half way from where it can usually be pulled carefully from the front (with the drive out of the machine).

The old belt must be found and removed before the new one is installed. Depending on the failure, the belt may have snapped, lost its elasticity, or devolved in an oily goo. If the latter, then you may need to clean up any sticky remnants.

The broken belt on my E12 can be seen in this image:

In this case, I think the previous owner of my MDS-E12 had replaced the belt with an elastic band - the original belt is black!

With the old belt removed, the spindles can be seen through the front of the drive mechanism:

Hooking the belt around the large spindle inside the drive isn't too difficult with a small screwdriver or plastic tool. But then the lip on the front of the drive makes it nearly impossible to stretch the belt over the smaller spindle in front.

The solution is to use a hooked tool, such as these Tekton hooks:

Use one of these to carefully extend the belt from the large wheel to the small one. Don't mind if the belt gets a little twisted - this will be solved as it spins.

And with that, the repair is complete! Carefully reinstall the metal shroud, then the two ribbon cables, screw the mechanism back in using the brass screws, and close the case. Enjoy your working MDS-E12!

  • guides/repair/e12-belt.txt
  • Last modified: 8 months ago
  • by kgallen