Grounding - Seagate ST12400N Product Manual

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10.2.1.3 Physical interface
The dimensions of the connector (J6) mounted on the Main PCB to interconnect the drives is shown in Figure
10.2.1-2. It is a 12 pin, 6 jumper position gold header type connector. Only pins 5 and 6 are used for connecting
the Reference Index signal cable, as shown in Figure 10.2.1-2. Pin 6 is REFIND+ and Pin 5 is ground.
.157
+/- .010
Figure 10.2.1-2. Configuration select header specification. (Connector used has 12 pins).
10.3

Grounding

Signal ground (PCB) and HDA ground are connected together in the ST12400 drive and cannot be separated by
the user. The equipment in which the drive is mounted is connected directly to the HDA and PCB with no electri-
cally isolating shock mounts. If it is desired for the system chassis to not be connected to the HDA/PCB ground,
the systems integrator or user must provide a nonconductive (electrically isolating) method of mounting the drive
in the host equipment.
The interface physical characteristics for the "NC" models are given in Figure 11.6.3-1b and in Table 11.6.3-1c.
The "sync"" signal is included among the 80 pins of the I/O connector.
Product Manual - Hawk 2 Family SCSI-2 (Volume 1), Rev. B
.485 max
.020 +/- .001
(square)
.0787
typ
.394 +/- .010
.0787 typ
.157
+/- .010
.236 max
.048 min
.033 +/- .004
.090
-.128