Hytera PD78XG Service Manual

Service Manual GPS Circuit
23
4.4 Troubleshooting Flow Chart
GPS circuit check
The GPS module
outputs normally?[1]
Check the power
supply.
The channel from GPS to
OAMP is normal?
GPS PIN17 outputs 2.8V voltage?
Replace abnormal RC and
check OMAP.
Replace the
GPS module.
Replace U501.
Replace Z501.
No
Yes
Yes
No
Yes
Yes
No
No
Yes
No
No
L506 outputs 2.8V
voltage?
U501 is normal?[3]
Z501 is normal?[4]
Replace the GPS
module.
The power supply for GPS is
normal?[2]
Yes
No
Description of Normal Situations:
[1] Detect with a multimeter. The voltage of TP502 changes within the range 1.2V~2.8V.
[2] Voltage at L502 and L505: about 3.3V.
[3] Gain for U501 (@1.57542GHz) : >15dB.
[4] Insertion loss for Z501 (@1.57542GHz): <4dB.

Hytera PD78XG Specifications

General

Brand	Hytera
Model	PD78XG
Category	Portable Radio
Language	English