NX-720H(G)/720H
33
TROUBLE SHOOTING
Model Name
Frequency Range
[MHz]
Original TX-RX
unit Number
For Service TX-RX
unit Number
NX-720H(G) (GPS model) : K
136 - 174
X57-8230-10
X57-8230-12
NX-720H : K
136 - 174
X57-8230-11
X57-8230-13
Replacing TX-RX Unit
■
TX-RX unit Information
Failure diagnosis of the GPS section.(Built-in GPS model only)
Overview: When the GPS function does not operate, use this fl owchart to determine the problem.
Note:
The transceiver supplies the voltage to the GPS antenna and the voltage is checked when the transceiver is turned "ON".
When the voltage is lower than the specifi ed value, "G ANT FAIL" is displayed for 2 seconds before entering user mode.
(At this time, the expected defect of the GPS antenna is a short. This error message does not appear when the expected de-
fect is an open .)
Positioning is not carried out normally.
When the power supply is turned
ON, "G ANT FAIL" is displayed.
Power is not
supplied to the
KRA-40.
Verify the connection of KRA-40.
(SMA connector)
Verify the connection of the SMA
connecting cable.
CN801 - E04-04
9
2-05
Verify the supply voltage of the
KRA-40.
L802 : 3.0V
Verify the backup voltage to the
GPS module.
L806 : 3.3V
Connect the cable to the CN801
correctly.
Verify the power supply voltage
after removing the KRA-40.
L802 : 3.0V
(The KRA-40 may be broken)
Replace the KRA-40.
(The GPS power supply circuit may
be broken)
Check IC407 and its surrounding
parys.
(The backup power supply is faulty. )
Check IC 406 (33A).
The output of the GPS data is
verified.
IC801(5pin) : Square wave form
(The RXD circuit is fauity.)
Replace D512.
(The signal line parts are faulty. )
Verify each part.
Connect the KRA-40 correctly.
Verify the TXD data output from the
GPS module.
CN802 : Square wave form
Verify the RXD data line.
D512 : Square wave form
Verify the RF input signal line.
L801,C821,C824,R842,R843
ASIC IC is abnormal.
(The Buffer
IC
may be broken)
Replas IC801.
(The GPS module may be broken)
Replas A801.
When an abnormal
value is confirmed.
When an abnormal
value is confirmed.
When an abnormal
wave form is confirmed.
When an abnormal
wave form is confirmed.
When an abnormal
condition is confirmed.
When an abnormal
condition is confirmed.
When a normal
value is confirmed.
When a normal
condition is confirmed.
When a normal
condition is confirmed.
When a normal
value is confirmed.
When a normal
wave form is confirmed.
When a normal
wave form is confirmed.
When a normal
condition is confirmed.
When an abnormal
condition is confirmed.
When an abnormal
condition is
confirmed.
When a normal
condition is confirmed.
When an abnormal
value is confirmed.
When a normal
value is confirmed.
When a normal
wave form is
confirmed.
When an abnormal
wave form is confirmed.
Major parts for a GPS circuit
• GPS module (A801) : W02-3768-05
• Buffer IC (IC801) :TC7WH126FUF
• Filter (L801) :L79-1958-05
• GPS active antenna : KRA-40 (option)
Summary of Contents for Nexedge NX-720H
Page 83: ...NX 720H G 720H 83 MEMO ...
