HP 7925D Service Manual page 125

Troubleshooting 7925
Table 4-4. Motherboard PCA-A7 Signal Distribution List (Continued)
COMMENTS
To Power and Motor Regulator PeA pin
A9Jl·20.
To Power and Motor Regulator PCA pin
A9Jl-22.
To Indicator PCA pin All J1-10,
To Spindle Logic PCA pin A8Pl-J..
To Fault Indicator PeA pin A12Jl-7.
From Indicator PCA pin Al1Jl-l1.
From READ ONLY switch - S5.
J3
A7
J2
MOTHERBOARD PCA
7
K
3
J1
14
XA6P1
A6
R/W
PREAMPUFIER PCA
XASP2
AS
TRACK
FOLLOWER PCA
XASP1 J2 J1
A4
8
J
H
12
17
16
XA4P2
DRIVE CONTROL PCA
F
6
N
13
XA3P2
A3
SERVO PCA
XA3P1 J1
A2
XA2P2
I/O SECTOR PCA
XA2P1 XA1P2
A1
HEAD
ALIGNMENT PCA
XA1P1
DEFINITION
Read Data A
"Not" Power Supply Failed PSF
RDA
SIGNAL
MNEMONIC
ROB Read Data B
RET
Retract Heads
RH "Not" Restore Home
ROl Read Only 1
R02 Read Only 2
RS
"Not" Rur. j:lindle
RUN "Not" Run
RWFL "Not" Read with Write Fault LED
SB "Not" Servo Balanced
SCL Sector Clock
6
SEL Drive Selected
SELL "Not" Drive Selected LED
SEN "Not" Servo Enable
SK Seek
DENOTES SIGNAL SOURCE DENOTES BIDIRECTIONAL SIGNAL
4-58