Voltage Checks - Seagate ST8741J Maintenance Manual

Voltage Checks
VOLTAGE CHECKS
The following procedure provides an overall check of the de
voltages used by the drive. Table 2-2 shows the voltages
required by each drive component. See the diagrams manual for
specific information concerning voltage test points.
Prior to performing this procedure you should be thoroughly
familiar with drive operation. with all information in section
1. and with the safety information in the front of this
manual. Refer to figure 1-2 (component locator) for pin
orientation of connectors J80 and Jl5 on the control board.
CAUTION
Because some voltage measurements are on pins
adjacent to each other. it is possible to
touch both pins simultaneously. thus causing a
short circuit. A short circuit will cause
serious damage to drive electronic
assemblies. Therefore. use extreme caution
when performing the following steps.
1.
Command continuous seeks between cylinder o and 256.
2. Connect voltmeter ground lead to J80-9 (chassis ground).
3. Measure between ground and the appropriate connection
points to check the following voltages:
Voltage
Connection
s12ecif ication
+5 volts
J80-20
+4.85 to +5.25 volts
-5 volts
J80-22
-4.90 to -5.30 volts
-12 volts
J80-23
-11.4 to -12.6 volts
+24 volts
Jl5-12
+22.8 to +25.2 volts
+12 volts
J80-21
+11.80 to +12.20 volts
Ground
J80-9
2-4
TROUBLE ANALYSIS
83325720 B
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