The FD-55GFR is a 5.25“ double sided high density floppy drive made by TEAC. It is part of their FD-55 series and was introduced in the beginning of the 1990s. There are multiple variants that are listed below. All variants use metal belts to facilitate head movement and lock the disk with a lever. Head loading is either done with a solenoid or via mechanical linkage. The drive can read and write at high density and double density and only read at single density.

The FD-55GFR model has a number of variants the differ in color, head loading type, circuit boards and more. They can be identified via the label that is located on the back of the drive (connector side).

The 141-U variant has a Dark Beige (PC-AT Gray) front bezel and a solenoid head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B motor board.

The 142-U variant has a Dark Beige (PC-AT Gray) front bezel and a mechanical head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B motor board.

The 143-U variant has a Dark Beige (PC-AT Gray) front bezel and a solenoid head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B motor board.

The 149-U variant has a Dark Beige (PC-AT Gray) front bezel and a mechanical head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B motor board.

The 149-U5 variant has a Dark Beige (PC-AT Gray) front bezel and a mechanical head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B or Sankyo SB94A motor board.

The 159-U variant has a Dark Beige (PC-AT Gray) front bezel and a mechanical head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B motor board.

The 184-U variant has a Light Beige (PS/2 Beige) front bezel and a solenoid head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B motor board.

The 193-U variant has a Light Beige (PS/2 Beige) front bezel and a mechanical head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B motor board.

The 197-U variant has a Light Beige (PS/2 Beige) front bezel and a solenoid head loading mechanism.

It uses the 13332117-000C control board and the Kumagaya 771V4-3101B motor board.

The 552-U variant has a Dark Beige (PC-AT Gray) front bezel and a solenoid head loading mechanism.

It uses the 13332094-00E control board and the Kumagaya 771V4-3101B motor board.

The 588-U variant has a Gray front bezel and a solenoid head loading mechanism.

It uses the 13332094-00E control board and the Kumagaya 771T1-3101 motor board.

The 595-U variant has a Light Beige (PS/2 Beige) front bezel and a solenoid head loading mechanism.

It uses the 13332094-00E control board and the Sankyo LB02B motor board.

The 612-U variant has a Light Beige (PS/2 Beige) front bezel and a mechanical head loading mechanism.

It uses the 13332094-00E control board and the Kumagaya 771T1-3101 motor board.

The 612-U variant has a Light Beige (PS/2 Beige) front bezel and a mechanical head loading mechanism.

It uses the 13332267-00D control board and the Kumagaya FD881 or Sankyo SB94A motor board.

13332094-00e.pdf

View PDF

13332117-000c.pdf

View PDF

13332267-00d.pdf

View PDF

When removing or swapping the control board the Track Zero alignment is lost and has to be realigned. The Track Zero alignment is adjusted by loosening the control board screws and sliding it forward or backward. If the board is to far back the head assembly will never reach the sensor and will hit the back end of travel. In this case the floppy controller might try to reach zero multiple times, causing a fast repeating knocking noise.

The Track Zero alignment can be performed by following these steps:

1. Loosen the control board screws so that it can slide back and forth with some resistance.
2. Slide the control board all the way backward (towards the connectors).
3. Repeat until Track Zero alignment is correct:
   1. Move the control board forward (towards the front bezel) by about 0.25mm.
   2. Try to read a disk or use KryoFlux track calibration mode (“dtc -v360 -i4 -c1”).
      1. If the disk reads fine or KryoFlux shows reading of track 0, then the Track Zero alignment should be OK.
      2. If the disk doesn't read or KryoFlux shows no track, then continue.
   3. Stop the disk reading or KryoFlux track calibration mode.
4. After reaching a good control board position it is advised to check the alignment multiple times to ensure that it is working all the time.
5. Tighten the control board screws, make sure not to move the board while doing so.

Not all drives will be able to seek 84 tracks without a small modification.

The modification can be performed by following these steps:

1. Place a flat-head screwdriver on either side of the front spring that holds down the head assembly guide rods, as pictured.
2. Tap the back of the screwdriver lightly but firmly to move the spring towards the spindle motor.
3. Do this for both sides of the spring.