Tandy TRS-80 Model II User manual

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--
ervlce
TRS-BO®
Hard Disk Drive
CUSTOM MANUFACTURED IN THE U.S.A. SY RADIO SHACK, A DIVISION OF TANDY CORPORATION

Hard Disk Service Manual
----------- TRS-aO ® -----------
Table of Contents
Warnings ...
1/ Specifications
2/ Connections
. . . .... . ..
........ . . ... . ..
l
2
4
3/ Replacement Procedures
4/ Overview. . . . . . • . . . . . . .. . . . 6
8
5/ Printed Circuit Board Artwork
9
7/ Parts Lists
6/
8/
9/
Wiring Diagrams
Schema tics . .
Theory of Operation • • •
Power Supply . • • .
Hard Disk Controller
Hard Disk Interface . . . • .
·
14
• 16
• • 18
••• 24
• 24
• • 29
• 49
10/ Supplement to Hard Disk Drive Service Manual . . 54
Copyright 1982 Tandy Corporation
Fort Worth, Texas 76102, U.S.A.
AlI rights reserved.
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____ H_a_r_d_D_1_' s_k TRS-SO ®
Service Manual
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
W A R NIN G S
* * * * * * ** * * * * * * * * * * * * * * * * * * * * * * *
Do not mo"e the Hard Disk Dri ve Uni t unless the Spindle Lock
on the bottom of the unit is in the locked position. Movinq
the unit even two feet without locking the Spindle Lock could
result in damage to the disk media.
Before operation of the Hard Disk Drive, the Spindle Lock must
be put in the unlocked position. To do this, carefully tilt up
tl-)e uni t and loosen the screw w11ich holds the locking bracket.
position the bracket to the side in the indented area and
tiqhten the screw.
DO NOT TURN THE DISK DRIVE UNIT UPSIDE DaWN.
'rhe spindle on the bottom of the unit must only be rotated
clockwise as viewed from the bottom of the unit. If the
spindle is rotated in the incorrect direction, media scoring
and head damage could result.
Do not move the Hard Disk Drive unit while the drive is
running. P~rmanent damage to the drive may occur resulting in
the loss of information or replacement of the disk.
DO NOT USE THE INIT COMMAND EXCEPT AS A LAST RESORT OR UNLESS
THE DATA ON DRIVE 4 18 SAVED ON AFLOPPY DISKETTE.
If the Hard Disk system will nct boot up, try ta find the
cause of the problem before using the INIT command. When INIT
is used, Drive 4 is reformatted and aIl data is lost.
When the unit is opened~
1. Never rotate the damper 10cated on the bubble unit without
AC power applied.
2. DO NOT OPEN THE BUBBLE UNIT. IT IS NOT FIELD SERVICEABLE.
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____ H_a_r_d_D_1_" s_k TRs-ao ® S_e_r_v_i_c_e_M_a_n_u_a_l _
1/ SPECIFICATIONS
POWER REQUIREMENTS
AC Power Requirements
50/60 Hz +/- 0.5 Hz
100/115 VAC installations (90 te 127 V at 1.lA
typical)
200/230 VAC installations (100 to 253 V at 0.6A
typical)
Fuse - 6 amp, fast-blow
DC Power Requirments
+24 VDC +/- 10%, 2.8A typical during stepping
(0.2A typical stepping steady state, non-stepping)
+5 VDC +/- 5%, 2.0A typical during stepping
(3.6A typical nen-stepping)
DIMENSIONS
Heiqht
width
Depth
Weight
ENVIRONMEN'r
Ambient Temperature
Relative Humidity
Maximum Wet Bulb
Heat Dissipation
Altitude
WARM-UP PERIOD
Minimum On Power-Up
Minimum ta Turn System On
After Turning System Off
HARD OrSK DRIVE
Disk Organizatien
Tracks per Unit
Tracks per Platter
Sectors per Track
Bytes per Secter
Cylinders per Disk
Average Latency
Retational Speed
6 inches (15.24 cm)
18.5 inches (47 cm)
19.25 inches (48.9 cm)
17 lbs. (7. 73 kg)
50 to 115 degrees F.
(la te 46 degrees C.)
8% te 80%
78% nen-condensing
150 watts (511 BTU/hr) Max.
eperating: a te 6000 feet
(0 te 1829 meters)
sterage~ -1000 te 12000 feet
(-305 to 3656 meters)
2 minutes
15 seconds
1024
512
34
256
256
9.6 rnsec
3125 rprn
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Hard Disk Service Manual
------------ TRS-SO ® -----------
SPECIFICATIONS (cont'd)
Recording Density
Flux Density
Track Density
Storage Capacity (Hard Disk)
Unformatted
Bytes per Track
Bytes per Surface
Bytes per Drive
Formatted
Bytes per Drive
6270 bpi
6270 fci
172 tpi
8704
2.23M
lO.M
8.SM (primary drive)
8.9M (secondary drive)
256
32
76
622,592
TRSDOS-HD FORMATTED FLOPPY DI8KETTE
Storage Capacity
Bytes per Sectors
Sectors per Track
Tracks (single-side)
Bytes per Diskette
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____ H_a_r_d_D_i_s_k TRS-SO ®
2/ CONNECTIONS AND POWER-UP
Service Manual
The primary and secondary units should be connected as
illustrated below. Don't forget to connect the power cord for
the computer and each Hard Disk Drive Unit.
Modelll
Primary Unit
Power-Up
Secondary Unit
Secondary Unit
Secondary Unit
1. Be sure aIl floppy diskette drives are empty and aIl
components are turned off.
2. Turn Drive 4 (the Primary Drive> ON.
Be sure Drive 4 is turned ON first or data may be lost
or destroyed.
3. Turn aIl Secondary Drives ON. Allow l minute warm-up for
the Disk Drives.
4. Turn the Computer ON.
5. Turn aIl peripherals (including Floppy Disk Expansion
Unit) ON.
If the operating system is stored on Hard Disk (TRSOOS-HD),
the Computer will go to Drive 4 and automatically load the
operating system. Refer to the Hard Disk Owner's Manual
and the TRS-SO Model II Owner's Manual for operating
instructions.
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____ H_a_r_d_D_i_s_k TRS-SO ®
When turning OFF the system . . .
Service Manual
1. Turn aIl peripherals (including Floppy Disk Drives) OFF.
2. Turn aIl Secondary Hard Disk Drives (Drives 5-7) OFF.
3. Turn the Primary Drive (Drive 4) OFF.
4. Turn the Computer OFF.
Always be sure Drive 4 (the Primary Drive) is the last disk
drive turned OFF. If Drive 4 is not the last drive turned off,
data could be darnaged or destroyed.
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____ H_a_r_d_D_i_s_k TRS-SO ®
3/ REPLACEMENT PROCEDURES
Service Manual
Replacement procedures contained in this manual are limited to
case disassembly, removal and replacement of subassemblies,
and case assembly.
Before beginning repair, disconnect aIl external cables from
the rear connector panel and BE SURE that the Spindle Lock is
in the locked position.
DISASSEMBLY
1. Remove the top row of screws (5) from the rear panel and
lift off the case top.
2. To rernove the hard disk controller board, remove aIl
cables from the board (data cables, hard disk expansion
cable, controller connecting cables, power harness).
Rernove the five screws and split washers from the
controller board.
3. To remove the hard disk power supply, remove the six
smail black screws which secure the power supply cover
to the bottom of the unit and lift off the cover. Loosen
aIl cables. Remove the six screws and washers which hold
the power supply board.
4. To remove the bubble unit, perform the following steps:
a. Rernove aIl cables from the bubble unit controller
board and rernove the screws which secure the board.
Twist the nylon retaining clips 90 degrees and
carefully lift off the controller board.
REASSEMBLY
1. Replace stepper board, bubble unit, and bubble controller
board. Be sure that the wire connector on the Index Sensor
goes to pins land 2 on the PCB.
2. Fasten the power supply in the bottom of the unit by using
six #6 screws and washers and aiso reconnect the power
cables.
3. Replace the power supply cover and fasten it using six #6
black screws.
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____ H_a_r_d_D_i_sk TRS-SO ®
Service Manual
4. position the hard disk controller board on top of the
power supply cover with the edge connector toward the rear
of the unit. Fasten the board using five #6 screws.
5. Reconnect all cables (data, hard disk expansion,
controller, power harness). Be sure that the data cables
are connected so that the cable cornes from the left-hand
side of the plug when looking from the front of the unit.
6. Replace the case top and five #6 screws in the rear panel.
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____ H_a_r_d_D_l._
e
s_k TRS-SD ® S_e_r_v_i_c_e_M_a_n_u_a_I _
4/ OVERVIEW
The TRS-SO Hard Disk Unit consists of two non-removable S-inch
disks spaced approximately l inch apart. There are four
Read/Write heads (one on each side of each plâtter> which move
towards or away from the center of the disk as needed.
The Disks and Read/Write heads are fully enclosed in a sealed
chamber. A special air filteration system prevents dust and
other particles which destroy data from reaching the disks.
Another filtering system allows pressure equalization with the
"outside" air pressure.
UNDER NO CIRCUMSTANCES MUST THE CHAMBER BE UNSEALED IN THE
FIELD. ACLASS 100 CLEAN ROOM ENVIRONMENT IS NEEDED FOR
UNDER-THE-BUBBLE REPAIR.
The Hard Disks have their own built-in error detection and
correction scheme. These errors are due to minor defects in
the media as weIl as signaIs from external sources. There will
be no more than 12 tracks per head with defects. Of these 12
tracks, no more than 4 tracks will contain multiple errors.
On aIl Hard Disk Units, flaws in the media are identified at
the factory before the disk drives are delivered to the
customer. Attached to the bottom of each disk drive unit is a
"Media Error Map". This map identifies the flawed tracks on
that particular unit.
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Hard Disk Service Manual
------------ TRS-SO ® -----------
5/ PRINTED CIRCUIT BOARDS
r:
1
Jl
+SV GN0
1
O~
ABl DEF
Ul TA:O: 1
r:
1
Jl
dl
+SV GNO-'
00
1
Ul TAd
Revision A board
Revision B board
Front Panel Driver Printed Circuit Board - Component Side
Rev A•
Front Panel Driver Printed Circuit Board - Circuit Side
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____ H_a_r_d_D_i_s_k TRS-SO ®
Service Manua1
Hard Disk Contro11er Printed Circuit Board - Component Side
Eladio Ihaell---------
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Hard Disk
•
TR5-BO®
Service Manua1
Circuit Side
Hard Disk Contro11er Printed Circuit Board
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____ H_a_r_d_D_i_s_k TRS-SO ®
~
~ -
~ -
~ -
~ -
~ -
~ -
.- -
Service Manua1
Hard Disk Interface Printed Circuit Board - Circuit Side
Eladio Ihaell---------
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____ H .... a... r_d D..._i_s..;.;k TRS-SO ®
Service Manua1
6/ WIRING DIAGRAMS
BROLJJN
~ ~AC
r---------+------~I~P 1
5RlZEN + + GRN CHASS/S GROUNDJNG
DI"? K r-------;;rv:T'":"'7ï
H
-;-;, T~E;;:;--------+-----4-----J + +~W-H-I T-E----4 SC Ç?, EW
r------------+----~----l t- +B
[7~Iv' E+ +t--_----1~_+_------R-O _l.U_N--J
BLACK. B
r---------------------l + +~-____l~_+_-----=-=-L:.....:~~C.~I(----J
++
TERMINAl:
BLOC,K
13LACI<.
POWER
'SUPA-Y
AC Wiring Harness
BLAc..~
SLAce
,~ ~
1
l5[ACt:
'~
fiLACt
L1
~LAcr
'v"'""
6LItC)(
~ .L"'\
12
'17 'J
RUJ
,1 2
WH/TE
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'=
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--- 34l'''b.. ..L:'\. 34
"
RED 1
""'-' 5
~~
r-~n
TO ~AIOOO
C.O~n?OLLER.
t30ARD
W~/TE
YELLDW
1
l
V2. CC
V3 V':J
v~ l
POWER ~UPPL1
DC Wiring Harness
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Hard Disk Service Manual
------------ TRS-SO ® -----------
ACT LI WP LT
WPTS
FRDNT
PANEL
PI
JI
lD~'VER MARD)
Front Panel Driver Board Wiring Diagram
Front Panel Driver Board Wiring Charts
Front Panel
Bubble
,JI
pl
Liqhts
J2
P2
Controller
ll
Active/WP l l
6C-S
22 N.C.
8A-l*
33
Acti ~le
2 2
7E-l
44
Write
Protect
5B-ll*
5 5 write
Protect
33
N.C.
6 6
Write
Protect
44
J2-5
*may appear
at these
designations
on sorne
boards.
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