HP 7925D Service Manual page 122

7925 Troubleshooting
Table 4-4. Motherboard PCA-A7 Signal Distribution List
(Continued)
COMMENTS
"Not Used.
"Not Used.
"Not Used.
Two-way data bus to and from controller.
Two-way data bus to and from controller.
J3
A7
J2
MOTHERBOARD PCA
J1 XA6P1
A6
R/W
PREAMPLIFIER peA
XASP2
L
AS
TRACK
FOLLOWER PCA
XASP1 J2 J1
A4
XA4P2
DRIVE CONTROL PCA
XA4P1 XA3P2
SERVO PCA
A3
L
XA3P1 J1
A2
XA2P2
I/O SECTOR PCA
XA1P2
A1
HEAD
ALIGNMENT PCA
XA1P1
DEFINITION
Internal Control Bus Bit 2
M M
Internal Control Bus Bit 3
10
10
Internal Control Bus Bit 4
9 9
Internal Control Bus Bit 5
7 7
Internal Control Bus Bit 6
K K*
Internal Control Bus Bit 7
J J
Internal Control Bus Bit 8
H H*
Internal Control Bus Bit 9
6
Internal Control Bus Bit 10
Data
"Nor' Data
DC Write (Current Sense)
Differential Data Bus
L
"Not" Differential Data Bus
10
Data AGC
H
Internal Control Bus Bit
1
DDB
06
SIGNAL
MNEMONIC
03
02
DGC
05
07
08
010
DATA
01
DCW
DATA
09
04
DENOTES SIGNAL SOURCE DENOTES BIDIRECTIONAL SIGNAL
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