
CCS Technical Documentation
Troubleshooting Instructions RF
NPM-10
Issue 1 03/2003
Nokia Corporation Confidential
Page 25
Figure 17: GSM850 transmitter troubleshooting chart
Figure 18: TXP, VPCTRL_G and TXC
GSM850 band, Power level 5, Channel 190
Black trace: Txp
Green trace: Vpctrl @ R713 input
Blue trace: Vpctrl_G @ R713 output
Red trace: TXC
Measure Power
on ANT with
Power Meter or
RCT
> 31 dBm
Measure TX
input power
at TX1 pin
of Z700:
Power ~ 32 dBm
Measure Pout
at pin 6 of PA:
33 dBm
Measure Pin
at pin 7 of PA:
~ 0 dBm
Measure
OUT_G_TX
Buffer input:
~ 1 dBm
Measure BAL
input to Z603
0 dBm
With Scope
check :
VTX= 2.8 V +
discretes around
No
No
No
No
No
No
Yes
With Scope check
on Ant. switch
Vant1 = 2.4 to 2.8V
Vant2 = 0 V
Yes
Check R759,
L702
Check Z700
( Antenna switch )
Yes
Check L709
( Coupler )
Yes
With Scope
check
VPCTRL_G at
pin 8 of N700:
( See figure 18 )
Yes
Check N700
( PA )
Yes
With Scope
check :
VTX_B_G =2.8 V
Yes
Check buffer
V702
+
discretes around
Yes
Check Z603
( TX SAW filter)
Yes
Check TXIP and
TXQP
( See figure 19 )
Yes
Check
Base band
Yes
With Scope
check TXC
( See figure 18 )
NO
Check V700
( detector )
+
discretes around
Yes
Check Mjoelner
+ the serial bus
NO
NO
NO
NO
NO