Technical Manual

9-2
6. Always wear a conductive wrist strap when servicing this
equipment. The Motorola part number for a replacement wrist
strap that connects to the table mat is 42-80385A59.
Voltage
Measurement and
Signal Tracing
It is always a good idea to check the battery voltage under load. This
can be done by measuring the OPT_B+ pin at the universal connector
on the back of the radio, with the radio keyed. The battery voltage
should remain at or above 7.0Vdc. The battery should be recharged or
replaced as necessary prior to analyzing the radio.
In most situations, the problem circuit may be identified using a dc
voltmeter, RF millivoltmeter, and oscilloscope (preferably with
100MHz bandwidth or more). The “Recommended Test Equipment,
Service Aids, and Tools” section in the ASTRO Digital XTS 3000
Portable Radios Basic Service Manual outlines the recommended tools
and service aids which would be useful. Of special note is the
8180377E58 Housing Eliminator, which allows the technician to open
the radio to probe points while in operation.
In some cases dc voltages at probe points are shown in red on the
schematics. In other areas diagrams may be included to show time
varying signals which should be present under the indicated
circumstances. It is recommended that a thorough check be made
prior to replacement of any IC or part. If the probe point does not have
a signal reasonably close to the indicated one, a check of the
surrounding components should be made prior to replacing any parts.
When checking a transistor or module, either in or
out of circuit, do not use an ohmmeter having more
than 1.5 volts dc appearing across test leads or use
an ohms scale of less than x100.
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C a u t i o n