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7925
Troubleshooting
C
A
8
D
4-39
4-41
4-43
4-45
4-47
4-49
4-51
14
---~
Mainframe Assembly
.
I/O Control System.
.
Spindle Rotation System
Head Positioning System
Sector Sensing System .
Read/Write System .
.
Fault Detection System
ALL D-TYPE FLIP-FLOPS ARE CLOCKED ON
THE RISING EDGE OF THE CLOCK SIGNAL.
NOTE:
COUNT 16
120 ms
COUNT 224
1667 ms
CANCEL
TIMEOUT
RESET
TIMEOUT
CLOCK
COUNTER
13
TCC
(135 Hz)
AGFL
DPS
ACRY
TOFl
R
ACRY
RET - CR8
TIMEOUT
INITIATE
CYCLE FF
120 ms
SK S
Q
TIMEOUT CYCLE
INITIATE
1667 ms
Q
TIMEOUT CYCLE
12
ACRY-~~-,.
(C9)
RH
FLT
RET
11
'---\;----/
SEE I/O CONTROL
SYSTEM DIAGRAM (C9)
RET
DWF
SEE READ;WRITE
SYSTEM DlAG RAM (B7)
~
ILFL
RWFL
DL - PIP
(B4)
SPU
(C5)
STOP
_
(C4)
WFLT
10
R-W
FAULT FF
W- AC
FAULT FF
W-AR
FAULT FF
S
SEE SPINDLE
ROTATION
SYSTEM
DIAGRAM
~~A~G~F~L~-----------+-------------+~----------------- ----------~------~-l---n
~
1 -
6 -
2 -
3 - - -
-1--
FLT (STATUS 81T 4)
I
SEE I/O CONTROL
SYSTEM DIAGRAM (B15)
R -W
W-AR
SEE SPINDLE{ ILF
ILF
ROTATION
DWF
(B3) & HEAD
pas
IT I
a
N IN G
TO F
<4--+---+--+-_e_
T
- O -
F
...
(C3, C4)
SYSTEM
DIAGRAMS
9
Q
1----4I.--
A_G_F~
C8F
Q I - - - I - - - - - - - - - - .
URG
WRITE
WRITE
WRITE
S
R
S
AGC
FAULT FF
DPS
CARRIAGE BACK
FAULT FF
ACRY
(B12)
NDPS
~------I--------------I------+--------IR
NDPS
~
- - t - _ . - - - - t
R
ONE
SHOT
1-------------
I
~L~I~R-;;;;:-A:;-
-
- -
--l
I
I
I
WeAR
I;;
I
AGC
III
I
Q
1---......
. . . . . ; ; W , , ; . . ; , R . . ; . . ; . F . . . ; ; ; ; L
~+___+_----.J2r_<
4
~
WRF L
)
4 )
J
1
®
>5V
+5V
®
J
1
<
I
: I
,
I
i
I
I
~I
~II
'
I
RWFL
(;;\'1
~
C8FL
<
)
7)
V
1-5V
+5V
\:9
<
6
r - - - - -.....
I
I
I
I
I I
W - AC
I~
[!g II
I
WAFl
~
®
ILFL
5
<
)
5)
\CI
15V
+5V
~
:
<
2
~---------
I
i
I
I
~~
[D~
!
I
I
/'1
/1 :
I
8
~
MHFL
)
8 )
®
15V
+5V
®
I
<
~ ~-TO-F-L---------I
______________________ J
L
~
CRB
(812)
NDPS
8
SEE HEAD
POSITIONING
SYSTEM
DIAGRAM (83)
~
DRDY
P1
P2
P1
_ _ }SEE HEAD
~
..........- - - - - - - - f - - + - - - - - - f ! - -...... -ACRY
.POSITION ING
SYSTEM
DIAGRAM
(B3)
D
ILF
SEE READ;WRITE {WRITE
r--------+--+-__
I---+---+~
SYSTEM
DIAGRAM (C7)
SEE HEAD {
I
PI
POSITIONING
CR8 ---<
S ~-------+------+---""----~
DIAGRAM (C5)
I
SEE I/O CONTROL (811),
SECTOR SENSING (C5)
1
& READ;WRITE (86)
SYSTEM DIAGRAMS
~
I
P2
SEE
READ;W~ITE
SYSTEM DlAG RAM
+5 VDC
+5 VDC
13.3K
+12V
26.1K
SEE SPINDLE {
ROTATION
SYSTEM DIAGRAM
RUN
~..-.---~---,
(B4)
IC03/ICI4
CPS
IC02/ICI3
6
+12V
5.11K
5.62K
6.81K
31.6K
+12V
SEESPINDL.E{
r------ -- --- ---- -- -------- -- ---- -- ---- ------ -------- - ----
ROTATION
TCC
---<
V f--P_1
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - t
SYSTEM
DIAGR~M
>-....
S_K
(_A-io 14 _)
-<
1'2
~P-2--------------------------------------------------
...,
I
R
I
H
6
I
L
I
D > - - - - - - - - - - - - - - - - - - I . . - - - - + - - - - - - - - - - - I
I
J
I
CYL
11
>-----------------+----l~-----'
I
URG
I
(D7) ---< K
I
ACW---<
(C12)
K
I
DCW ---< J
(D12)
I
MHS ---< l
F
~
-- - -- -- -- -- -- -- -
16 - - - - - - - -
_-1--
~ .-J
DRIVE CONTROL PCA-A4
61.9K
P1
P1
P2
I
P2
+10 VDC-< 6
45
I
P1
+5V~
q.+5V
,
I
:
+12V
---<3,C~+12V
I
:
-12V~2,B~-12V
5
I
SERV~-;;-
-
- - - - - - - - -
~=O;;;N;:;;1
P2
SK
SYSTEM DIAGRAM
(08)
I
N
~
I
SKH
AGC
I
I
ILLEGAL
CYLINDER
ICA
I
ADDRESS
I
DETECTOR
ICA
I
I
CYLINDER
ADDRESS
I
SEE I/O CONTROL
L
DO
-
D9
PI
---------
.J::!:::I
_ _
-.-J~
SYSTEM DIAGRAM
'if
'"
(B6)
- - -
F -
15 -
S -
-
11
~I
1
7 ,8,9,10,11,
'yf
F,H,K,l,M
J
~,7,9,10,11,
I - -_ _
p..... :~)
»-
~/'--1-0--
H,J,K,L,M
!
I
I
I
I
I
SEE SPINDLE {
I
ROTATION (D3)
&
HEAD
PSF,-< N
POSITIONING
(C5) SYSTEM
I
T
6.8tl F
DIAGRAMS
V
L
~-------
SEE SPINDLE
ROTATION
SYSTEM DIAGRAM
SEE
MAINFRAME
ASSEMBLY
WIRING
DIAGRAM
SEE I/O CONTROL
SYSTEM DIAGRAM
(B14)
~
SEEK CHECK
(STATUS BIT 2)
U
>--
CL2
(D14)
8
>--
CL1
(A14)
I
7
>--
SPS
(D14)
ACRY
ACRY
ILLEGAL
HEAD ADDRESS
(HEAD> 8)
I
R
4
CURRENT
LIMIT
LATCH 2
Q
~--+--I
L-L-E-G-A-L----lIII...-'
SECTOR
ILLEGAL
ADDRESS
CYLINDER ADDRESS
(SECTOR> 63)
" - (CYLINDER> 822) OR
MULTIPLE SEEK COMMANDS
CPS
(A6)-~~--+-------------------~1""""'+
RCLe SE L
----+---+--......---~
(84)
I
D
C
Q I - - - - - - - - - + - - - - ,
SEE I/O
CONTROL
SYSTEM
DIAGRAM
C
ILLEGAL
HEAD ADDRESS
FF
CARRY
D
J
CARRY
+5V
3
+5V
4
CONSTANT ( = 7
for
7925)
+5V
XMS - SE L - - - - - - L . - . ,
4
CONSTANT
(=192
for
7925)
AD R - SE
L-------4~-~
RP~
. : . _ _ -
-
_ _
-.J
CONTROL
BUS
CONTROL,
BUS
3
SEE
I/O CONTROL
SYSTEM
DIAGRAM
(B4 & D5)
~~~~----------------------------------I
SEEKe(~~~
SK
P2
N
~~~~-------------------l
P1
1K
@:gJ
CURRENT
10
~
LIMIT
I
LATCH 1
'---\r-'
1.94 K
SEE SPINDLE
ROTATION
SYSTEM
DIAGRAM
(C14)
I
I
L __
EIL2
EIL1
2
...
I_C_ 12
-e
14 . . P_1
..._ ..
ICI9
-24V
~
------,----.
421
POWER AND MOTOR REGULATOR PCA-A9
J1
I
+12V
I
I
TEMPERATURE
I
SWITCH - A9S1
I
4.64K
OPENS AT
I
72.8
±
2.8°C
12.1K
(163
±
5°F)
I
+36V
CLOSES AT
I
64.4 ± 3.4° C
9 ......- -........
~,
'--V-J
(148
±
6°F)
10K
SEE
I
I
ICO,
8
SPINDLE
T
ROTATION
SYSTEM
I
I
II
DIAGRAM
•
(B13)
I
-36V
4.64K
J1
9
<
IC09/ICI8
..
~---------e:<
16
I
CL21
I
I
I
L
~
L
J
rT=~
C-;V;:J
r=~
FOLLOWER
,PREAMPLIFIER
1
CHAMBER
I
PCA-A5
I
I
PCA-A6
I
ASSEMBLY
I
L
PA
I
I
p!-~-i
I
I
JRJ
1 7 - U
..J
L
15 -
S
..J
1 - 7 - 8
IC05flCI6
r
L __
IC_0_6 _ _
!
B
D
c
A
7311-31 D
4
6
8
9
10
11
12
13
14
Figure 4-29. Fault Detection System, Functional Diagram
4-51/4-52
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