Motorola MTX series Theory/Troubleshooting Manual

37
TROUBLESHOOTING FLOW CHART #2B
(800/900MHz Receiver RF)
No-High SINAD
YES
Check Comp.
Q1, CR5, C54,
C55, L24, C56
& C57
Inject
73.350MHz
at Pin 1 FL1
-110 = 12dB
SINAD
Check
Freq.
Pin 14-U3
VDC at
Pin 18 U3
0 or 5V
Inject
73.350MHz
at L20/C35
-113-12dB
SINAD
Replace
J401
Check U3 &
Ext. Comp.
Check Comp.
FL1, L20,
C35 & C36
Refer to
DC Switch
Chart #3B
Check T1 OK
Change U2
Replace
U5
Check
VDC
Pins 3 & 4
Check C204 OK
Refer to
Chart #5B VCO.
Check Comp.
L32, L34, L10,
C4, C27 & C11
Ok Replace U1
Check L8 OK
Refer to DC
Switch Chart #3B
Check C82,
C90, C91 OK
Replace U2
Replace
U2
Check C84 OK
Replace U2
Remove L30,
C12 & recheck if
still bad.
Replace U4
Check S101,
C151, L127,
C149, CR109
& C141
Inject
Carrier at
Pin 2 of U5
12dB SINAD
-108dBm
VDC
Pin 4, 6, 11
U2
NO NO
YES
YES
NO
NO NO
Inject
Carrier
Pin 1 U5
12dB SINAD
-104dBm
VDC
Pin 1-15
U2
NO
NO
YES YES
Inject
Carrier
Pin 2 U4
-117dBm=12dB
SINAD
Check
RF Level +
Freq. of Lo
in -6dBm
VDC
Pin 10-U2
VDC
Pin 12-U2
Inject
Carrier
Pin 1 U4
-113 = 12dB
SINAD
Inject
Carrier
Pin 1 S101
-116 = 12dB
SINAD
NO
NO
YES
NO
NO
NO
YES
NO
NO
YES
YES
YES
YES
MAEPF-23442-O
YES
YES
NO

Motorola MTX series Specifications

General

Brand	Motorola
Model	MTX series
Category	Portable Radio
Language	English