Editing Tandon TM100-2

{{Infobox computer peripheral
| name          = Tandon TM100-2
| image         = [[File:Tandon TM100-2A floppy drive.jpg|260px]]
| caption       = Tandon TM100-2A — the TM100-2 revision shown
| manufacturer  = Tandon Corporation
| type          = Full-height 5.25" floppy disk drive (double-sided, 48 TPI)
| interface     = Shugart-style 34-pin
| compatible    = [[IBM PC (5150)]] (late units), [[IBM PC XT (5160)]], PC-compatible clones
| media         = 5.25" DS DD diskette, 48 TPI, 40 tracks/side
| storage       = 320 KB (PC DOS 1.1, 8 sectors/track); 360 KB (PC DOS 2.0+, 9 sectors/track)
| weight        = ~3 lb (1.35 kg)
| predecessor   = [[Tandon TM100-1]]
| model         = TM100-2, TM100-2A
}}

The '''Tandon TM100-2''' is a full-height 5.25" double-sided double-density floppy disk drive, supplied as the standard floppy drive in most [[IBM PC (5150)]]s from late 1982 onward and in every [[IBM PC XT (5160)]]. It stores 320 KB per disk under PC DOS 1.1 (360 KB under PC DOS 2.0+). A minor revision, the '''TM100-2A''', is functionally identical from the controller's perspective and visually nearly identical.

== Specifications ==

* '''Form factor:''' 5.25" full-height.
* '''Heads:''' 2 (double-sided).
* '''Tracks per inch:''' 48.
* '''Tracks per side:''' 40.
* '''Encoding:''' MFM, 250 kbit/s.
* '''Power requirement:''' +5 V at ~600 mA and +12 V (per the Tandon TM100-1/-2 Product Specification).

== Common Faults ==

* '''Drive belt failure''' — the single most common failure on a TM100-2 today. Replacement fabric-reinforced belts are sold by Console5, Best Electronics and others.
* '''Stepper grease drag''' — the lead screw lubricant hardens over decades. Symptom: the head carriage either does not step at all, or steps unevenly between cylinders, producing read errors that move with track number. Clean with isopropyl alcohol; re-lubricate sparingly with white lithium grease.
* '''Head alignment drift''' — after many years the heads may need re-aligning. A disk-based alignment tool and an analog oscilloscope are required.
* '''Track 0 sensor dirty''' — clean with isopropyl alcohol on a foam swab.
* '''Write-protect sensor failure''' — the photo-interrupter that detects the write-protect notch can drift; a permanently write-protected drive often has a dirty or failed sensor.

== Tandon Drive Select Jumpers ==

The TM100-2 ships with the drive-select jumper at '''DS2'''. The IBM FDD ribbon cable has a 7-wire twist between the two drive connectors which remaps DS2 to DS0 on whichever drive sits at the end of the cable (drive A). Both drives must therefore be jumper-set to DS2 — the cable handles the remapping. The drive at the end of the cable also requires its terminating resistor pack to be present; the middle drive must have the resistor pack removed.

== References ==

* [https://www.minuszerodegrees.net/manuals/Tandon/Tandon%20TM100-1,%20TM100-2%20-%20Product%20Specification%20and%20User's%20Manual%20-%20Manual%20part%20number%20179059-001.pdf Tandon TM100-1, TM100-2 Product Specification], minuszerodegrees.net.
* [http://www.bitsavers.org/pdf/tandon/TM100-1_TM100-2_48TPI_Operating_and_Service_Manuals_1983.pdf Tandon TM100-1, TM100-2 48TPI Operating and Service Manuals (1983)], bitsavers.
* [https://www.minuszerodegrees.net/5150_5160/tandon_tm100/tandon_tm100-2_problems.htm Tandon TM100-2 in IBM 5150/5155/5160 — known problems], minuszerodegrees.net.

== Related Pages ==

* [[IBM PC (5150)]]
* [[IBM PC XT (5160)]]
* [[Tandon TM100-1]] — the single-sided variant
* [[IBM FDD Adapter]] — the controller card

[[Category:IBM]]