Voltage Measurement And Signal Tracing - Motorola ASTRO XTSTM 4000 Detailed Service Manual

Troubleshooting Procedures: Voltage Measurement and Signal Tracing
Motorola
Part Number
RLN4460
RVN4181
NOTE Parts U1401 and U1304 are not field repairable. For failures relating to U1401
and U1304, the mainboard has to be replaced.
4.3

Voltage Measurement and Signal Tracing

It is always a good idea to check the battery voltage under load. This can be done by checking the
OPT_B+_VPP pin at the radio CE connector (pin 3). The battery voltage should remain at or above
7.0 Vdc. If the battery voltage is less than 7.0 Vdc, then it should be recharged or replaced as
necessary prior to analyzing the radio.
In most instances, the problem circuit may be identified using a multimeter, an RF millivoltmeter,
oscilloscope (preferably with 100 MHz bandwidth or more), and a spectrum analyzer.
!
C a u t i o n
6871620L01-C
Table 4-1. Recommended Service Tools (Continued)
Description
Portable Test Set
Customer Programming Software
(CPS) and Tuner Software
When checking a transistor or module, either in or out of
circuit, do not use an ohmmeter having more than 1.5 Vdc
appearing across test leads or use an ohms scale of less than
x100.
Application
Used for radio performance checks.
Connects to radio's CE connector and
allows remote switching and signal
injection/outputs for test equipment
measurements.
CPS allows customer-specific
programming of modes and features.
Tuner software required to perform
alignment of radio parameters. Can be
used for XTS 5000, XTS 4000 and
XTS 2500 products.
4-3
May 28, 2008