HP 7925D Service Manual page 243

Appendix A
AS
A6
A1* A2* A3 A4
TRACK
R/W
A7
SIGNAL
DATA PCA MICROPROCESSOR SERVO PCA DRIVE CONTROL peA
FOLLOWER PCA
PREAMPLIFIER
MOTHERBOARD peA
DEFINITION
PCA
peA
COMMENTS
MNEMONIC
XA1P1 XA1P2 XA2P1 XA2P2 XA3P1 XA3P2 XA4P1 XA4P2 J1
J2
XA5P1 XA5P2 XA6P1 J1 J2 J3
RET Retract Heads 13
Ri=r
"Not" Restore Home
II
H
•
R01
Read Only 1
18
From READ ONLY
/ /
..
</>
switch - S5.
t
R02 Read Only 2
~~JI.
J
AS
"Not" Run Spindle
~11~ltl)11
3
To Spindle Logic PCA
pin A8P1-J.
RUN
-
From Indicator PCA
"Not" Run 16
-
pin A11J1-11.
"Not" Read with Write Fault
7
Will
To Fault Indicator PCA
R"WF't
LED
pin A12J1-7.
> f i f
gjllill
SB
"Not" Servo Balanced 17
SCL Sector Clock 6
III
·/f ..• iii
/
)/
i i / ·if
SEL Drive Selected
8
i/<
8
II
-
--
To Indicator PCA
SELL
"Not" Drive Selected LE D
7
pin Al1Jl-10.
To Power and Motor
SEN
"N at" Servo Enable
K Regulator PCA pin
A9J 1-20.
/ / <··········>ii/
SK
Seek
\
Wi
rt
~;I-
N 12
Si<R"
"Not" Seek Home U
• WHEN DSU IS INSTALLED, SL.OTS Al AND A2 CONTAIN HEAD
DENOTES SIGNAL SOURCE
ALIGNMENT peA AND I/O SECTOR PCA, RESPECTIVELY.
A-70
7925