HP 7925D Service Manual page 123

Troubleshooting 7925
Table 4-4. Motherboard PCA-A7 Signal Distribution List (Continued)
From Indicator PeA pin Al1Jl-18.
COMMENTS
To Power and Motor Regulator PCA pin
A9Jl·50.
·Not Used.
To DRIVE READY lamp via Indicator PCA
pin AllJl-7.
Identifies 7920/7925 to DSU.
From FORMAT switch - S4.
To DRIVE FAULT lamp via Indicator PCA
pin AllJl-6.
J3
A7
J2
MOTHERBOARD peA
F
N*
R
T
A
XA6P1
B
A6
R/W
PREAMPLIFIER PCA
XASP2
AS
TRACK
FOLLOWER PCA
XASP1 J2 J1
A4
3
M
XA4P2
DRIVE CONTROL PCA
R
13
12
XA4P1 XA3P2
A3
SERVO PCA
XA3P1 J1
F
A2
4
13
XA2P2
I/O SECTOR PeA
XA2P1 XA1P2
A1
HEAD
ALIGN MENT PCA
XA1P1
DEFINITION
Door Locked and Pack In Place
"Not" Destructive Preset
SIGNAL
MNEMONIC
OLe PIP
DRDY Drive Ready
DRDYL "Not" Drive Ready Lamp
DSUT "Not" DSU Drive Type
DWA "Not" Decrease Write Current A (13mA)
DWB "Not" Decrease Write Current B (6.5mA)
DWC "Not" Decrease Write Current C
(3.25mA)
ECS
Energize Carriage Solenoid
FLT Drive Fault
FLTL "Not" Drive Fault Lamp
FMT Format Pack
HSO Head Select Bit 0
HSl Head Select Bit 1
HS2 Head Select Bit 2
HS3 Head Select Bit 3
DENOTES SIGNAL SOURCE DENOTES BIDIRECTIONAL S,·GNAL
4-56