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Amstrad CPC664 & CPC6128 Fault Diagnosis

WARNING: Any repairs you make are at your own risk!

Problem Solution
This problem can be identified when the following are true:
  • The disc is in the disc drive,
  • A drive access is made (e.g. CATalogue),
  • The drive motor is on briefly,
  • The disc access light on the front of the drive is lit briefly,
  • The error message, 
    Drive A: disc missing, (R)etry, (I)gnore or (C)ancel"
    is displayed
This is a common problem. The 3" disc drive uses a rubber drive belt, and after some time and use, the belt will wear out causing this problem. The solution is to replace the drive belt.

Replacing the drive Belt:

These instructions refer to the CPC6128 computer, but should be similar for all CPC disc systems.

  1. Removing the disc drive
    • Disconnect computer from monitor and power supply,
    • Place the computer onto a work surface,
    • Turn computer over so the base is facing upwards,
    • Locate and remove all visible screws, (don't forget to remove the screws on the side)
    • Turn computer over so the keyboard is facing upwards with the disc drive on the right and facing towards you,
    • Gently lift the keyboard away from the base. The keyboard is attached by a ribbon cable to the main P.C.B. on the left side. To avoid damage to this cable, the keyboard should be placed so it is facing down and to the left of the base.
    • Locate and remove the screws holding the disc drive to the base,
    • With disc drive in hand, carefully remove the ribbon cable and power connector from the back.
  2. Replacing the drive belt
    • Place the disc drive onto a table with the base facing up, the connector at the back, and the front of the disc drive pointing towards you,
    • Locate and remove the small screws holding the P.C.B to the disc drive housing.
    • Locate and remove the connecting leads from the stepper motor and drive motor. The connectors attach to the P.C.B on the left and right.
    • At this point, you should be able to move the P.C.B. in a limited way. Do not pull on the P.C.B. because it will still be attached from underneath. You should be able to move the P.C.B. and see the rubber belt.
    • Using a suitable tool (a small screwdriver), hook the belt and lift it free. You should be able to pull it out.
    • Take the new drive belt and gently hook it into place.
    • Check the belt is not twisted and does not move or come free when the motor is moved by hand.
    • Assemble the disc drive (follow the dissassembly operation in reverse)
  3. Reassemble the computer Assembling the computer is done by following the instructions in reverse

Note: Be careful when disassembling the disc drive, there is a small metal pin which can easily fall out. If this pin falls out, then you will need to locate the hole it came out of which is on the casing of the drive underneath the P.C.B.

To disconnect the PCB on the disc drive:

  • Amstrad PtNo: Z70312: remove CN2 and CN3
  • Amstrad PtNo: 30002: remove CN3,CN4,CN5 and CN6
  • Amstrad PtNo: 30001: remove CN3, CN4 and CN5