Page 1
After Sales Technical Documentation
THA–4S
TROUBLE SHOOTING
GUIDE
Original, 12/95
NMP Part No. 0275180
Page 2
THA–4S
After Sales
Troubleshooting Guide
AMENDMENT RECORD SHEET
Amendment
Number
Technical Documentation
Date Inserted By Comments
Page 2
Original, 12/95
Page 3
After Sales
THA–4S
Technical Documentation
Troubleshooting Guide
TROUBLESHOOTING GUIDE
CONTENTS
Introduction 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Faults 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DC Faults 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logic Faults 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Receiver Faults 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmitter Faults 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Display / Keyboard Faults 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Call Setup Faults 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Earphone / Modulation Faults 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Page No
Original, 12/95
Page 3
Page 4
THA–4S
After Sales
Troubleshooting Guide
Introduction
The following pages in this guide contain useful flow charts designed to
assist with system faultfinding.
General Faults
STAR T
Off Current
consumption >
0.5mA
Y
Will turn into
local mode
N
Technical Documentation
DC Fault
N
Logic fault
Y
Receiver O.K
Y
Transmitter O.K
Y
Earphone
level/modulation
OK
Y
Display/keypad
working
N
N
N
N
Receiver fault
Transmitter fault
Earphone
level/modulation
OK
Display/keypad
fault
Page 4
Y
Call set–up
Y
END
N
Call set–up fault
Original, 12/95
Page 5
After Sales
THA–4S
Technical Documentation
DC Fault
DC fault
Power consumption
greater than 60ouA
when phone is off
Check voltage
across R131 or
R162 < 2.5mV
Troubleshooting Guide
Check the following:
N
–XPWON = 0V
–XPWOFF = 0V
–XRES = 0V
If OK change N101
Y
Check the following:
–voltage across B100,R401;R403,R269
–Switches V221,V216;V217
–Change display – if OK change N203
Original, 12/95
Page 5
Page 6
THA–4S
After Sales
Troubleshooting Guide
Logic Fault
Logic fault
Power drops off, does
not assume local mode
Check clock
signal of D100/
pin 7 4.85Vpp
4.8MHz
Technical Documentation
Check
N
VL1 N101/pin 20
VL2 N101/pin 3
4.85 V
N
Check the following:
–Soldering of N101
–Vbat N101/pin 1
–DETIN N101/pin 12>1.23V
If OK change N101
Y
is XRES 0V in
N101/pin 8
Y
Check the following:
–Soldering of B102
–Soldering of D101
–DC voltage of B102
If OK change B102
Check
N
MCU clock
D101/pin 69
4.85Vpp/4.8MHz
Y
Check the following:
–Soldering of X101
–MBUS circuit V121
–D101/VL1, Vref, GND
If OK change D101
Page 6
Original, 12/95
Page 7
After Sales
THA–4S
Technical Documentation
Receiver Fault (1)
Receiver
fault
Simplex
sens TX (off)
OK
Y
is
TX spectrum
OK
Y
Replace duplex
filter Z201
N
N
Troubleshooting Guide
Channel 380 RX level –60dBm PROBE 10:1 10 Mohm/14pF
Transmitter fault
N
Noise or AF
signal at X101
pin 4 XEAR
Y
test point
J200 middle
channel
2–4Vdc
Y
NN
Is VRX
(V221c) 4.85V
Y
AF signal at
C117
N
Y
Earphone fault
Is Vref
(N101/pin 2)
4.85V
Y
Check:
V221, V222, R295
R291, R292
R230
AF signal at
C222 (DAF)
Y
Check:
C105, N100,
C116
N
N
Replace N101
Injection level
at N201/pin 1
–32dBm 86.4
MHz
N
B
Y
A
Check RF
level at C249
–22dBm
968.25MHz
Y
Injection level
at C208 –24dBm
968.25MHz
N
Check:
V201, C207,
C208, C229,
C249
Y
Check:
N
RF level C251
–25 dBm
14.4Mhz
N
G200,N202
Y
Check:
V204/c
4.75Vdc
N
R289, VRX=4.85V
Y
N
V205/c
2.4Vdc
Check:
R217, R216,R220,
V204
Y
Check:
Check:
R222=0.9Vdc
N
R218,R219,L206,
R290,L207,R222,
C239,
Y
Negative
voltage on
V206/A
N
Negative
voltage on
C244
N
Check:
R224, R223
Baseband
Check RF
level at N202 /6
–35dBm
968.25MHz
N
Check:
R221, R300, C259
C230
Original, 12/95
Y
Y
Check:
C253, R232, R238
N202
Y
Check:
R225,L208
Page 7
Page 8
THA–4S
After Sales
Troubleshooting Guide
Receiver Fault (2)
Check
R202, R326, C329,
V200
Check G200
Technical Documentation
B
Check RF
level at G200/out
N
1.5Vpp/14.4
N
Y
Check V225/c
Y
N
1.8 Vdc
Check N201
pin4 = 1.9 Vdc
N
Y
Injection level
at C265
–32dBm
14.4 MHzMHz
Y
Check
R226, R303, R299, V225,
R202, C329, C326, V200
Check RF
level at C220
–66 dBm 86.85
MHz
A
Check
L204, C215, N201, L205
C225
Check
V200
Y
Check
V202, R203, R204
Check
Z206
Check
L201,L202, VR201,
C207
N
RX level –30dBm
Check RF
Y
level at C210
–55dBm
86.85MHz
N
Y
Check RF
level at C206
–47dBm
86.85MHz
N
Y
Check RF
level at C206
–53dBm
881.4 MHz
N
Replace duplex filter
Z201
Page 8
Y
Check RF
N
level at L217
–66dBm
881.4 MHz
N
Check RF
level at V200/c
–50dBm
881.4 MHz
Y
Check
Z202, C235
Original, 12/95
Page 9
After Sales
THA–4S
Technical Documentation
Transmitter Fault (1)
Transmitter
fault
Output power
N
TSYN = 4.85Vdc
Y
N
V222/pin 5
4.4Vdc
Check
V222, R293, V223,
R298, N202
Channel 380 RX level –60dBm
PROBE 10:1 10 Mohm/14pF
Y
Re–align in Tesla
Check
N
R295, R230, V222
Y
Check
C274, C275, C273,
L210, C268, V208,
C271
Y
Alignment
level 2 in Tesla
possible
N
A
Troubleshooting Guide
N
VCTCXO, G200,
D101/pin 64 (PWM)
C318, R296
N
R273, R241, V214
C306
Check
Check
Y
Tx freq.
836.4000MHz
Y
Change of
power level
possible
N
N
R274 power
level 2
V>0Vdc
Check
Lock detect
is high
>4.0Vdc
Y
V216/c > 0Vdc
Y
N
RF level L214
–27dBM
N
Y
V210/c =3.2Vdc
N
Check
R254, V209, V210,
R255, R251, R252,
R253
Y
Y
Y
Freq. at L214
131.85MHz
Y
Check
R233, N202
N
RF level
at N202/pin 15
–34dBM
N
Check
C280, R250, N202
Y
Voltages at J201
1–4Vdc
Y
N
between N202/pin 15
Check loop filter
and V208
N
POWER_LEVEL
CTRL change
possible
Y
N
V215/pin 13
2.4Vdc
Y
N204/pin 1
>0Vdc
N
N
POWER_LEVEL
CTRL>0Vdc
Y
N
Check
D100
Y
A
Original, 12/95
B
CD
E
Page 9
Page 10
THA–4S
After Sales
Troubleshooting Guide
Transmitter Fault (2)
A
RF Level
V212/c
–39dBm
836.4MHz
B
Check
R280, R224, R237
N
V212/c= 4.2Vdc
Y
C
Check
V216, R279, R280
V215
N
Check
R262
D
Check
R276, R277
V203
Technical Documentation
E
Y
Change of
VCONT possible
Y
Power level 2
Bit 1>4Vdc
Bit2>4Vdc
Check
N
V216, V215, R279,
R281, R282
Check
R266, R267, D101,
N203
N
Y
RF Level
V213/b
–40dBm
836.4MHz
Y
RF Level
V213/c
–32dBm
836.4MHz
Y
RF Level
V219/b
–41dBm
836.4MHz
N
Y
Check
R297, L209, C293,
R265, R264
Check
C278, C279, L211,
RF level L214
C281, V211, C283,
–27dBM
C284, R258, C287
Check
V213, R261, R260,
R259
RF Level
C316
–23dBm
836.4MHz
Y
Power level 7
Bit 1>4Vdc
Bit2<1Vdc
N
Y
Check
N203
Y
RF Level
C295 > –8dBm
836.4MHz
Y
Check
Z201, X101
N
Check
C290, Z210, C317,
L213
Page 10
N
Check
V219, C219, L212
N
Check
VCC1, N203
Original, 12/95
Page 11
After Sales
THA–4S
Technical Documentation
Display / Keyboard Fault
Display/Keyboard
fault
N
Display 0k
Y
Change display
module
Y
Display OK?
Troubleshooting Guide
Check
–soldering X400
–X400/pin5 Vbat
N
–X400/pin12 VL2
–X400/pin 16 –V –2.1V
–X400/pin 14 GND
–X400/pin7 LCD_Clock 280kHz
Change Keyboard
foil
Y
Lights OK?
Y
N
Keypad foil
OK?
Y
Check
–Short circuits in the keyboard layout
–Col 0–2 = 0V when no key is pressed
N
D101/pin 44
4.85V with
light on
Y
Check
–Switch V414, V419,
–V415
N
Check
loading of lights line
If OK change D101
Original, 12/95
Page 11
Page 12
THA–4S
After Sales
Troubleshooting Guide
Call Setup Fault
Call Setup
fault
Does
the phone
assume SERV
mode?
Y
Technical Documentation
If programming is not possible
N
Subscriber data
OK?
Y
N
check
–MBUS circuit (V121)
–D102 control line soldering
check operation of:
–ST signal
–SAT/DSAT signal
–Transmitter
–Synthesiser
–VCO
if all OK change D100
RSSI operating?
Y
Data detection
of D100/pin 27?
Y
Replace D100
N
N
check
–D101/pin 54 A/D con
–N201/pin 12 for RSSI
check
–D100/pin 27 for data signal
–D201/pin 9 for signal
Page 12
Original, 12/95
Page 13
After Sales
THA–4S
Technical Documentation
Earphone /Modulation Level Fault
–Voice modulation 2,9kHz div. @ 1kHz
–Volume 3 ( in NANTIC vil. step 8.)
–Compandor on
–XMIC line 65mV/!kHz equals
2,9kHz div.
Troubleshooting Guide
Original, 12/95
Page 13
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