Controller Troubleshooting (Sheet 2) - Motorola MTM800 User Manual

TROUBLESHOOTING CHARTS: 450-470MHz

Controller Troubleshooting (Sheet 2)

Measure the 16.8MHz
and the 32.768kHz
signals with a scope
Yes
Replace
controller
U1100
No
Replace
Y0101
From Sheet 1
A
No
16.8MHz
signal at collector
signal at TP5331
of Q0100
?
Yes
32.768kHz
signal at U0100
pin 18
?
signal at Y5363
No
32.768kHz
signal at U0100
pin 3
?
Yes
Before replacing
No
U0100 check
associated
components
Yes
Yes
16.8MHz
?
No
Yes
Check
16.8MHz
transistor
stage
pin 3
Q5351
?
No
Yes
2.8V DC
Before replacing
at C0324
Y5363 check R5364
?
No
9.3V DC
9.3V DC supply failure!
at C0308
Go to DC Supply Chart
?
Replace
U0307
Before replacing U5331 check
components between collector
Q0100 and U5331 pin 19, check
components between Y5363 and
U5331 pin 23.
Yes
5V DC
at U5322 pin 4
?
No
Yes
9.3V DC
at U5322 pin 5
?
No
9.3V DC supply failure!
Go to DC Supply Chart
9.1 - 5
Replace
U5322