TPDD: Difference between revisions

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Software related to these drives can be broken into 2 main categories, [[TPDD_client|clients]] and [[TPDD_server|servers]].
Software related to these drives can be broken into 2 main categories, [[TPDD_client|clients]] and [[TPDD_server|servers]].


A [[TPDD_client|TPDD client]] (or DOS) is software that uses a TPDD drive. This includes the "Floppy" that came on the utility disk that came with the drive, TS-DOS, and others.
A [[TPDD_client]] (or DOS) is software that uses a TPDD drive. This includes the "Floppy" that came on the utility disk that came with the drive, TS-DOS, and others.


A [[TPDD_Emulators|TPDD server]] (or emulator) is software that pretends to BE a TPDD drive. This includes LaddieAlpha, dlplus, and others.
A [[TPDD_server]] (or emulator) is software that pretends to BE a TPDD drive. This includes LaddieAlpha, dlplus, and others.
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==For "Model T"s==
==For "Model T"s==

Revision as of 04:44, 31 July 2021

Tandy Portable Disk Drive

There were two versions of the Tandy Portable Disk Drive, "26-3808 Tandy Portable Disk Drive" or "TPDD1", and "26-3814 Tandy Portable Disk Drive 2" or "TPDD2". Both were very similar. The original TPDD1 is a re-branded Brother FB-100.

Common features of both versions

Size, shape, weight
Batteris: 4 x AA
Wall power: 5.5mm x 2.1mm, 6vdc, center negative, 400ma (Tandy 26-3804)
Media: 3.5" DD, aka "720K" diskettes (not HD 1.44M)
Drive is single-sided. The disks may be single or double-sided, but the drive only uses one side.

Documentation

Tandy Portable Disk Drive

100K

Operation Manual
Software Manual
Service Manual
TPDD1 bootstrap procedure
Command Reference

Tandy Portable Disk Drive 2

200K, in the form of 2 100K banks

TPDD2 Operation Manual
TPDD2 bootstrap procedure
TPDD2 Sector Access

Parts

Belt

Standard size code: FRW-8.5

Search "FRW 8.5 belt" on Google or ebay

Cable

The "RS-232C" interface to the TPDD is actually 5v TTL (0v to +5v), while RS-232 serial ports use -12v to +12v. So the cable isn't just a cable, it has electronics inside the DB25 plug to convert the signal levels between TTL and RS-232.

Pinout

+------------------------------------------------+
|                                                |
|                                                |
|                 RS-232C                        |
|                   ___                          |
|               +--+   +--+              +-----+ |     
|               | 7 5 3 1 |              | (o) | |
|               | 8 6 4 2 |              |     | |
|               +---------+              +-----+ |
+------------------------------------------------+
1 GND
2 CTS
3 DTR
4 RTS
5 DSR
6 TXD
7 RXD
8 EB+ (External Battery +4.8 to +6v)

KiCAD source for schematic & pcb to build a cable

Assembly:
  • Solder all components to pcb per the render pics.
  • Pull the two un-soldered pins from the top of the socket and discard.
  • Cut the 9-pin plug off the serial cable. Strip the outer sheath back 1 to 2 inches. Strip each wire 1/8".
  • Put 2 to 3 inches of 1/2" diameter heat shrink on the serial cable. (don't shrink yet)
  • Identify which color wires go to which pins on the DB25 plug.
Find pin 2 on the db25
Find which color wire goes to pin 2 using a DMM continuity tester
Repeat for all the numbered holes on the PCB: 2,3,4,5,6,7,20
Cut any left-over wires short right at the cable sheath.
  • Solder the wires to their matching numbered holes, with the wires on the top side (without the transistors).
  • Put some hot-glue on the top side of the pcb in the "dog bone", press the end of the cable into the glue, and secure to the pcb with a zip-tie.
  • Add some hot-glue around the soldered wires where they meet the pcb to immobilize them.
  • Slide the heat-shrink up over the pcb and shrink.

TPDD:Other_Cable_Designs

Software

Software related to these drives can be broken into 2 main categories, clients and servers.

A TPDD_client (or DOS) is software that uses a TPDD drive. This includes the "Floppy" that came on the utility disk that came with the drive, TS-DOS, and others.

A TPDD_server (or emulator) is software that pretends to BE a TPDD drive. This includes LaddieAlpha, dlplus, and others.