Motherboard Pca-A7 Signal Distribution List - HP 7925D Service Manual

7925
Troubleshooting
Table 4-4. Motherboard PCA-A7 Signal Distribution List
To Carriage Back Detector.
COMMENTS
To Fault Indicator PCA pin A12J1-1.
Two-way control bus to and from
controller.
Two-way control bus to and from
controller.
To Fault Indicator PCA pin A12J1-6.
Exits A4P1-N to DSU and A2J1-24 to
controller.
Two-way control bus to and from
controller.
J3
J2
A7
MOTHERBOARD PCA
J1
3
J
2
c
XA6P1
A6
R/W
PREAMPLIFIER PCA
XA5P2
A5
TRACK
FOLLOWER PCA
XA5P1 J2 J1
s
A4
XA4P2
DRIVE CONTROL PCA
K
17
XA3P2
SERVO PCA
A3
16
XA3P1 J1
24
A2
E
XA2P2
I/O SECTOR PCA
J
XA2P1 XA1P2
A1
HEAD
ALIGNMENT PCA
N
XA1P1
Spare
DEFINITION
Carriage Back Supply
Automatic Gain Control
"Not" Control Bus Bit 2
"Not" Control Bus Bit 0
"Not" Carriage Back Fault LED
AC Write (Current Sense)
"Not" Access Ready
Attention
"Not" Control Bus Bit 1
"Not" AGC Fault
"Not" AGC Fault LED
Buttered Head Select Bit 0
Buffered Head Select Bit 3
Buffered Head Select Bit 1
Buffered Head Select Bit 2
SIGNAL
MNEMONIC
CBUSO
CBFL
ATT
CBUS2
BHS2
CBS
CBUS1
AGC
AGFL
AGCF
ACW
BHS1
ACRY
BHS3
BHSO
DENOTES SIGNAL SOURCE DENOTES BIDIRECTIONAL SIGNAL
4-53