User Guide

RH-17
Troubleshooting — RF CCS Technical Documentation
Page 46 Nokia Corporation Confidential Issue 1 04/2003
Table 4: RF and DC probing for Power detector AMPS mode
VCO Probing
Table 5: UHF LO Troubleshooting
Power Level
P_DET
Power measured at L801 DC level measure at C807
PWROUT
Dc level
measured
at J603
PL2 -10.2 dBm 1.42 Vdc
PL3 -11.5 dBm 1.57 Vdc
PL4 -16.9 dBm 1.70 Vdc
PL5 -19.7 dBm 1.83 Vdc
PL6 -23.4 dBm 1.89 Vdc
PL7 -27.9 dBm 1.94 Vdc
UHF LO at 1009.62 MHz for
channel 384
N503 UHF LO Tx Buffer Amplifier
TP21
TP22
Check gain
across N502
should be ~ 4dB.
Check Buffer Amp N502 has supply
voltage VR6 at pins 4 and 6. Check
components L520, R505, R506, R519,
R509, C510, C506, L503, R502 and
L771.
UHF LO at 1009.62 MHz for
channel 384
G502 UHF LO
TP23 Power approx. -2
dBm.
Make sure there is 2.7V at pin 3 of G502
checking components R515, C511 and
C501. Check that control voltage is
present at pin 1 of G502. If voltage is
2.7V, check TP24 with a RF probe to see
if UHF LO is present. Check L520, R506,
L516 and C516.
UHF LO at 1009.62 MHz for
channel 384
N507 Synth PLL
TP25 Power approx. –
21 dBm.
If LO is present but incorrect frequency
proceed to TP25 check control voltage
when PLL locked should be 2.0 Vdc.
Confirm Loop filter components C518,
C508, R508, R503, C509, R550, and
C550. Pay particular attention to C508,
as it is easily damaged. Check supply
voltage to N507 at pin 18 is @ 2.78
Vdc(VR4 via R501 is VPLL) and charge
pump input voltage VR1A is at 4.75 Vdc
at pin 20(check C504, R513 and C521).
VIO should be 1.8 Vdc at pins 15 and 16.
UHF LO at 1009.62 MHz for
channel 384
N507 VCTCXO input
CLK19M2_R at 19.2 MHz
TP26
TP29
19.2 MHz at
amplitude of
-28.0 dBm
Check that clock is present at TP26 at
19.2 Mhz C519. If not present proceed
to Table 6.
Check C513