5.25" Diskette Adapter

@DFFA.ADF 5.25" Diskette Drive Adapter (1.2MB card only!)

188-216 5.25" External, Internal Diskette Drive, and Diskette Adapter/A (summary only)
189-077 IBM PS/2 5.25-Inch External Diskette Drive, 5.25-Inch Internal Diskette Drive, IBM PS/2 5.25-Inch External Diskette Adapter/A

4869drve.exe 1.2MB Floppy Adapter Option disk
4869DRVR files in RAR archive
   IBMDSKT5.EXE - Installation Program for the 5.25-inch Diskette Device Driver
   $FDD5.SYS - DOS Diskette Device Driver
   EXT5DD.SYS - OS/2 Diskette Driver

4869 External Diskette Drive The much beloved "Battle Floppy"
Personal System/2 External Storage Device Cable (HDI-30 / DB37 used with P70/P75)

Early 5.25" 1.2MB / 360KB External Diskette Adapter
5.25" 1.2MB / 360KB External Diskette Adapter
   H025397 8590/95, 486SX-25MHz Diskette Data Loss
5.25" 360KB External Diskette Adapter Lacks any POS circuitry.
ADF Sections for 1.2MB Version
Drive Connector Assembly (Plastic "B" Box)

4869 External & Internal 5.25” Diskette Drive Compatibility and Part Numbers

5.25” FDD or Adapter 8525
8555 8573 8560
8565 8580
-001 360K 1 1 1 1 1 1 1 1
-001 Adapter 2 2 3/4 4 * 3/4 4 4
4869-002 N/A N/A 5 5 5 5 5 5
-002 Adapter N/A N/A 4 4 4 4 4 4
1.2 MB Int. FDD N/A N/A N/A N/A 6 6 6 6
1.2MB Adapter N/A N/A N/A N/A 4 4 4 4
1 -> 72X6759   (360KB DRIVE)   4 -> 15F7996 (ADAPTER/A CARD)
2 -> 72X6757   (ADAPTER)       5 -> 15F7993 (1.2MB EXT DRIVE)
3 -> 72X6758** ("B" BOX KIT)   6 -> 15F6912 (1.2MB INT DRIVE)

* The 8573 requires an External Storage Device Cable P/N 23F3230, not a 5.25” Diskette Adapter.
** P/N 72X6758 includes: adapter (72X6757), cable, Drive Connector Assembly (Plastic "B" box, 72X6755).

Adapter P/N 72X6757 (attachment group) (Pass-through only, it uses the planar FDC).

  • This adapter uses an internal cable to attach to the drive connector assembly in the "B" bay.
  • This adapter only supports the 360KB 5.25 external diskette drive.
  • This adapter is not supported in 8555, 8580 A21 / A31, and 8565. It is not required for the 8573.
  • No ADF or software device driver is required with this adapter. It will NOT show up in a slot.
  • System Programs and DOS will show the 5.25 external drive as drive "B"

5.25 INCH ADAPTER/A P/N15F7996 (adds another FDC, needs ADF and device drivers)

  • A ribbon cable is used only when an internal drive is attached.
  • Both the 4869-001 (360KB) and 4869-002 (1.2MB) External 5.25” Drives are supported.
  • Option diskette is required for configuration and diagnostics. The adapter will show up in a slot.
  • Device driver and installation program are needed to install it.

Any external or internal drives attached to it will be seen by the system as logically external. The O/S will assign this drive the next available drive designation. For example: if a 115mb hardfile is installed on a model 8580-111 and it is partitioned as C, D, E, F, the next available drive designation is "G. Your external drive will be booted as "G" during post when the device driver is being loaded.

Device drivers

If the device driver is being loaded during POST, the drive letter will be displayed on the screen.
To verify proper installation of the device driver refer to the section in the PS/2 SIM that discusses the "DASDDRVR" patch installation/verification. Replace the filename of "DASDDRVR" with "$FDD5.SYS" and follow the instructions.

Early 5.25" 1.2MB / 360KB External Diskette Adapter
FRU P/N 94X0839 (or 15F7996), FCC ID ANO9SA6451007 [P] [P] | [P] [P]

J1 34-pin floppy header
J2 DB37 external floppy
S1 Unused four position DIP switch
U1 NEC µPD72065C Floppy controller
U2 SED9420 VFO Data separator
Y1 32.000 MHz osc
Y2 19.200 MHz osc

The rest of the board is filled with 74xx logic. Japanese design.

David Beem says:
   I was sent an early version (883x & 884x date codes on the chips vs. ~903x on my later versions) of the "Diskette Adapter/A" that has a slightly different layout but with the same FRU & FCC ID.

All switch positions are up ("on") on mine; don't know what they do. Y1 & Y2 are reversed from the later board: Y1 = 32MHz, Y2 = 19.2MHz here. They are also the "full-can" crystals. U1 is a NEC 72065C (the diskette controller chip). U2 is a "SED9420", Epson SED9420 CMOS Data Separator for FDD. J1 & J2 are the same as the later board. Outside the identified components there is SMC TTL chips that fill every available position otherwise.

The switches were used during the development of the adapter. A newer release of the card will not have any switches. The card functions exactly the same regardless of the switch settings.

5.25" 1.2MB / 360KB External Diskette Adapter FRU P/N 15F7996

J1 34-pin floppy header
J2 DB37 external floppy
U4 15F8072
U12 NEC µPD765BC Floppy controller
Y1 19.200 MHz xtal
Y2 32.000 MHz xtal

U4 15F8072 may be similar to the Epson SED9420 CMOS Data Separator for FDD

Allows the 4869-001 or 002 to be attached to the 8550, 8560, 8570, or 8580 system unit or the diskette drive (6451006) to be attached to the Personal System/2 8560 or 8580 system unit.  A device driver is used with the 4869 or PS/2 Internal Diskette Drive (6451006). This adapter can accommodate up to two 5.25-inch diskette drives, one external and/or one internal drive in the following system configurations:

    MODELS 60, 80            MODELS 50,       MODELS
         ONLY                60, 70, 80      60, 80
4869-001 and  6451006        4869-001   or   6451006
4869-002 and  6451006        4869-002

David Beem weighs in with:
   I have the driver for this board (4869drve.exe). Interesting to note the 34-pin 'J1' is a conventional floppy pinout (no power on the connection) that gives you a standard 34-pin (read: clone) floppy data connection on the board. This is for the PS/2s that have a 5-1/4" bay & the separate drive power plugs.

The driver only recognizes the 5-1/4" drive types (360KB or 1.2MB), but will read a conventional 1.44MB drive fine (Identified as 1.2MB. You can also DRIVPARM it to make it appear like it should.). Can't supplant the regular floppy drives this way though: The attached drive is set up as the next available drive letter. If you have a compressed drive that the host partition is "H:" the attached floppy will be "I:". With both an internal & external drive attached to this board the internal drive is configured first. Only one drive can be on each of the connections. The internal ribbon cable should have no twists.

Tim Clarke boasts:
   Anyway, the point of all this is that I found that the 1.2MB could be configured as "Drive B:" by editing the system ADF to add the 5.25" drive codes, provided that the later version of SC.EXE (V2.20?) was being used.

H025397 8590/95, 486SX-25MHz Diskette Data Loss

Systems with a 486SX/25MHz [“H”] complex that use the VERIFY function during "Diskette-Like Operations" may fail, allowing bad data to be read from or written to a device without any error indication or other evidence of system failure.

* "Diskette-Like Operations" are defined as operations on any device attached to the diskette drive controller and are "seen" by the system as a diskette drive, such as some tape backup devices.

Note: Most "H" complexes have a bad DMA controller [U6 92F1428]. Late "H" complexes (made early 92 on) can have 10G7808 (known Good) or 10G4714 (Possibly Good).

H complexes with 48G8042 on sticker below CPU have U23.
Complex PCB is 06G6870, BIOS 07G0463, DMA 10G7808.

H complexes with 07G3152 on sticker below CPU do NOT have U23.
Complex PCB is 06G4561, BIOS 07G0463, DMA 92F1428.

Systems with the 486SX/25MHz [“H”] processor board and version 1.00 or 1.01 system partition are subject to this problem. Devices that rely on BIOS support are (potentially) supported after an update of the system partition to the latest level.

Except: The 5.25 inch Diskette Adapter/A uses a separate device driver (not BIOS), and DMA VERIFY. They are exposed to the problem after updating the system partition.

IBM PS/2 5.25 inch Diskette Adapter/A (#1007) (6451007)
IBM PS/2 4869-001 360KB External Diskette Drive
IBM PS/2 4869-002 1.2MB External Diskette Drive

Note: H complexes with the good DMA controller, 10G7808, MIGHT not be affected.

This tip replaces expired ECA100.

5.25" 360KB External Diskette Adapter FRU 72X6758

The 360KB adapter has three small ICs to the left of P3. The rest of the "adapter" is bare. This adapter is intended *only* for the 360K version of the IBM 4869-001 external 5.25" drive (embossed "Star" symbol in the faceplate of the drive).

>[The Drive Connector Assembly] 72X6755 is a card fitted to a plastic bracket making it fit into the second floppy bay of the 8570 (Ed. works with 50/60/70/80 card edge floppy) I got it from.  It had a connector on the side (34 pin header), which was connected by ribbon cable to the MCA card using a 34 pin edgecard socket (3M 5934).

David Beem again lays it out by saying:
   Nothing more than a pass-through MCA riser. You have to put in a bay adapter & 34-pin connecting cable too.

ADF Sections AdapterID DFFAH AdapterName "5.25-inch Diskette Drive Adapter"

         io 0280h - 0287h
         int 6

DMA Arbitration Levels
   DMA channel used during data transfer.  Ordinarily, <Level 3> is always selected.
      <"Level 3">,  1, 5, 7

Drive Connector Assembly 72X6755

Used on 8550, 8560, 8570, and 8580 models with card edge floppy sockets. Not for use with 8565 and 8580 A21 / A31.

34-position card edge slips into floppy socket and assembly clicks into place like a normal floppy.

Note the 34 pin header on underside of Assembly. The 34 conductor ribbon cable then goes over to the 5.25" 360KB External Diskette Adapter FRU 72X6758, where the card edge socket connector fits onto P2.

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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