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Repair guide

Replace the Famicom Disk System drive belt and reset the head

The Disk System drive runs on a rubber belt that perishes with age, and the old one can even melt onto the motor pulley. A new belt and a head position reset usually brings it back.

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Belt · Careful · about 90 minutes. Worth doing. Reports say this fix helps on many machines.

You are in the right place if: The disk will not spin, the drive grinds or stalls, or the system locks up while loading a disk.

Before you start

  • Use only disks you can afford to lose while testing. Old disks can be damaged by a misaligned head.
  • Do not force the head carriage. If it binds, stop and re-check the belt routing.
  • Keep disks away from magnets.

Board revisions and models

The Famicom version is the HVC-022 drive and HVC-023 RAM adapter. The Twin Famicom has the drive built in but the belt job is similar.

Parts you may need

  • Famicom Disk System replacement belt. the original perishes Amazon · eBay
  • Isopropyl alcohol. cleaning pulley and head Amazon · eBay

Tools

  • Precision screwdriver set. opening the drive Amazon · eBay
  • Cotton swabs. cleaning Amazon · eBay
  • Small flat tool for belt seating. avoid scratching Amazon · eBay

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Step by step

  1. Confirm the symptom Insert a disk you can afford to test with and listen. No spin or a stalled spin points at the belt. Do not force the disk.
  2. Remove all power Unplug the adapter and take out any batteries before opening the drive.
  3. Open the drive Remove the screws and lift the cover. Photograph the mechanism before you touch the belt or the head.
  4. Remove the old belt Pull off what is left. If it has melted onto the brass motor pulley, clean the residue off with isopropyl alcohol and a swab.
  5. Fit the new belt Seat the new belt over the motor pulley and the flywheel without twisting it. Make sure it is the correct size for the FDS drive.
  6. Clean the head Wipe the read head and the disk path gently with an alcohol swab and let it dry.
  7. Reset the head start position After a belt swap the head start position can be off, which can cause an Error 22. Follow a head alignment video and adjust in small steps.
  8. Reassemble and test Close the drive, connect the RAM adapter and run a known-good disk for several minutes.
  9. If it still fails Check the RAM adapter, connectors and the power board for damaged traces. A FDSLDR cable is an alternative way to load games.

Tips, tales and maybes

Found in write-ups and forum threads. These are other people's reports, not tested by us.

  • Story (Medium confidence). One restorer found the original belt had melted onto the brass motor pulley and replaced it with a new belt, then redid the head start position. Source
  • Watch out (Low confidence). Another owner found the belt worn out and the head unable to reach its end-of-track position, and gave up on the drive in favor of a FDSLDR cable. Source
  • Tip (Low confidence). A video guide on adjusting the head position is linked from the hitmanmcc write-up. Source

Guides we used

We wrote the steps in our own words from these. They have the photos and the full detail, so please read them and support their authors.

Boards and models vary, so check what is in front of you. A repair can involve hot tools, chemicals and, on some machines, dangerous voltages. You do it at your own risk.

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