Motorola APX 7000 Detailed Service Manual

Troubleshooting Charts: GPS Failure 5-47
5.18 GPS Failure
START
No GPS lock or poor
signal reception
GPS lock?
Connect GPS simulator to radio with a
minimum of 4 satellites at -120dBm,
turn radio on then wait 2 minutes
No
Yes
Reconnect the GPS/Combo antenna
and retry in stronger signal
environment (open sky), if still no fix
then try a new antenna
Check regulators U2220 for 2.8V
(measured at C2214 and C2219),
U2270 for 1.8V (measure C2275),
and U2284 for 1.2V (measure
C2285)
regulators
OK?
Replace faulty
regulator
No
Yes
Measure voltage on
reset signal at R2255.
is 1.8V
present?
Yes
Check for 32 kHz
at R2216
is 32kHz
present?
Check U6101
(CPLD) pin E2
(IO74) for
32kHz output
Check U6101
(CPLD) pin D12
(IO91) for 1.8V
No
No
Yes
No
is 26 MHz
present?
Yes
Replace Y2204
Verify communication with GPS IC by resetting radio while probing TP2205 and
TP2206 with an oscilloscope. TP2205 should show a short stream of data from the
GPS IC during a reset, after which TP2206 should show bootloading data from the
processor. Activity should be seen on both test points for successful comm.
No
comm
successful?
Yes
Check SAW filter FL2205
@ 1575.42MHz
is loss >
2dB?
Yes
Replace FL2205
Check regulator U2220 for 2.8V
(measured at C2214 and C2219)
regulator
OK?
Replace faulty
regulator
No
Yes
No
Check LNA U2217 @ 1575.42MHz from the input of C2208 to the output
of C2267 (radio must be powered and caps must be disconnected from
rest of circuit). Also verify the LNA enable is 1.8V by measuring C2216
is gain >
12dB?
No
Yes
Replace U2217
Check for 26 MHz at C2238
Replace SAW filter FL2207
and GPS IC U2206
Replace SAW filter FL2207
and GPS IC U2206
Check regulator U201 for 3V
(measured at C1305)
regulator
OK?
Replace faulty
regulator
Check LNA U1304 @ 1575.42MHz from the input of C1301 to the output
of C1308 (radio must be powered and caps must be disconnected from
rest of circuit). Also verify the LNA enable is 1.8V by measuring C1307
(RF board must be connected to expansion board)
No
Yes
is gain >
12dB?
No
Replace LNA U1304 (and SAW Filter FL1301
for 700/800/UHF1 or UHF1/VHF or UHF1/UHF2
or 700/800/UHF2 or UHF2/VHF or VHF/7/800 radios)
Yes
is 26 MHz
present?
Replace Y2204
No
Check for 26 MHz at C2238

Motorola APX 7000 Specifications

General

Digital Technology	P25 Phase 1 and Phase 2
Emergency Button	Yes
Frequency Range	136-174 MHz (VHF), 380-470 MHz (UHF Range 1), 450-520 MHz (UHF Range 2), 764-870 MHz (700/800 MHz)
Display	Color LCD
Encryption	AES, DES
Water Resistance	IP67
GPS	Yes
Bluetooth	Yes
Operating Temperature	-30°C to +60°C
Weight	391 g (with standard battery)