HP 7925D Service Manual page 240

7925
Appendix A
Table A-II. HP 7925H Motherboard PCA-A7
Signal Distribution List (Continued)
COMMENTS
* Not Used
J1 J2
A7
MOTHERBOARD PCA
J1
XA6P1
A6
R/W
PREAMPLIFIER
PCA
XA5P2
J
H*
AS
TRACK
FOLLOWER PCA
XA5P1 J2 J1 XA4P2
A4
DRIVE CONTROL PCA
XA4P1 XA3P2
A3
SERVO PCA
J
H
XA3P1 XA2P2
A2*
MICROPROCESSOR
PCA
A1*
DATA PCA
XA1P1
DEFINITION
I nternal Control Bus Bit 7
I nternal Control Bus Bit 8 08
07
09 I nternal Control Bus Bit 9 F 6
010
Internal Control Bus Bit 10
15*
*
Not Used
DCW
DC Wr i te (Current Sense)
J 5
DDS Differential Data Bus L L
l515'B
"Not" Differential Data Bus 10 10
DGC Data AGC M
H
DLePIP Door Locked and Pack in Place
o
From Indicator PCA
M
pin A11J1-18.
BPS
IINot" Destructive Preset P N*
*
Not Used
DRDY
Drive Ready 4
To DRIVE READY lamp
DRDYL "Not" Drive Ready Lamp
18 via Indicator PCA pin
A11J1-7.
i5WA
IINot" Decrease Write Current
18
A
A (13 mA)
"Not" Decrease Write Current
5WB 13 8
8 (6.5 mA)
• WHEN DSU IS INSTALLED, SLOTS Al AND A2 CONTAIN HEAD
DENOTES SIGNAL SOURCE
ALIGNMENT PCA AND I/O SECTOR PCA, RESPECTIVELY.
SIGNAL
MNEMONIC
A-67