Troubleshooting, Circuit Board And Schematics; Troubleshooting; Circuit Board Layout - Motorola MC3000 Operating And Installation Manual

Troubleshooting, Circuit Board and Schematics

Troubleshooting

Troubleshooting
The following table is divided into three columns; a column indicating the potential problem
description, an action column detailing the suggested verification or procedure to locate
the problem, and a column providing references to additional information, where applica-
ble.
Table 4-1: Troubleshooting the MC3000 Digital Deskset
Problem
The deskset will not key
the radio station trans-
mitter
The receive audio is low
or distorted.
There is a continuous
hum in the transmit or
receive audio
No Transmit LED or
other LEDs
The keypad does not
respond

Circuit Board Layout

The MC3000 deskset has two circuit boards. The top circuit board is attached to the top
housing and the bottom circuit board is attached to the bottom housing. The following dia-
grams show the component side of the top and bottom circuit boards and the key side of
the top circuit board.
4-2
Solution
Check the wiring to the radio and the deskset
RJ-45 connector.
Verify Fuse is OK.
Check the local junction wiring.
Check that the channel keying configuration
matches the requirements.
Ensure that the audio being received from the
radio station receiver is not distorted and that the
radio station receive audio level is between
80mV and 0.78V
RMS RMS
Check the equipment grounding and ensure there
are no ground loops.
Ensure the Tx/Rx audio wiring to the RJ-45
conncector is not damaged or not fastened tightly.
Check the fuse and replace with a Fast-acting
fuse 1A, 5x20mm GMA-1.
Do a LED test.
Check the PTT or monitor input on the audio port
is not activated.
MC3000 Digital Deskset Operator and Installation Manual
.
Reference
See Audio and
Data to the
Radio Table in
Chapter 2
See Line Input
Adjustment
Chapter 2
See Testing
Deskset Func-
tions Chapter 2
(6880309L15-A)