HP 7925D Service Manual page 121

Troubleshooting
7925
Table 4-4. Motherboard PCA-A7 Signal Distribution List (Continued)
Al
A2 A3 A4 AS A6 A7
SIGNAL
HEAD TRACK RM
DEFINITION
ALIGNMENT PCA I/O SECTOR PCA SERVO PCA DRIVE CONTROL PCA FOLLOWER PCA PREAMPLIFIER PCA MOTHERBOARD PeA COMMENTS
MNEMONIC
XA1Pl XA1P2 XA2P1 XA2P2
XA3P1 XA3P2 XA4P1 XA4P2 Jl J2 XASPl XASP2 XA6Pl Jl J2 J3
CBUS3 "Not" Control Bus Bit 3 Two-way control bus to and from
controller.
CBUS4 "Not" Control Bus Bit 4 Two-way control bus to and from
controller.
CBUS5 "Not" Control Bus Bit 5
Two-way control bus to and from
controller.
CBUS6 "Not" Control Bus Bit 6 Two-way control bus to and from
controller.
CBUS7 "Not" Control Bus Bit 7
Two-way control bus to and from
controller.
CBUSa "Not" Control Bus Bit 8
Two-way control bus to and from
controller.
CBUS9 "Not" Control Bus Bit 9
Two-way control bus to and from
controller.
CBUS10 "Not" Control Bus Bit 1.0 Two-way control bus to and from
controller.
CC Current Command To Power and Motor Regulator PeA pin
4
A9Jl-14.
CEP "Not" CE Pack Installed
V
CLA "Not" Clear Attention
5
COF "Not" Clear Offset
U
CPS
"Not" Controller Preset
R
CRB Carriage Back From Carriage Back Detector. Also. to
S
Power and Motor Regulator peA pin
A9J1-28.
CYL Set Cylinder
11 11
DO Internal Control Bus Bit 0
11 11
DENOTES SIGNAL SOURCE DENOTES BIDIRECTIONAL SIGNAL
4-54