User Guide

Nokia Customer Care RF Description and Troubleshooting
6255/6255i/6256/6256i (RM-19)
Issue 2 05/2005 ©2005 Nokia Corporation Company Confidential Page 53
VCTCXO Troubleshooting
Without 19.2MHz, the mobile terminal does not power up. This signal goes to the N7100,
N7000, D2800, and the UHF PLL. Check the test points in Figure 43 for the presence of
the 19.2MHz signal.
Figure 43: VCTCXO test point output values
Table 15 includes the descriptions and values for VCTCXO test points from Figure 43.
Table 15: VCTCXO Test Point Output Values
Test
Point
Description Value
1 F_REF_TX, clock reference to the N7000 ~ -9dBm
2 F_REF_RX, clock reference to the N7100 ~ -9dBm
3 CLK19M2_TIKU, clock reference to Tiku ~ -9dBm, and ~2 dB less on the other side
of R7204 (located adjacent to the D2800)
4 CLK19M2_LPRF, clock reference to the
Bluetooth subsystem
~ -9dBm
5 CLK19M2_GPS, clock reference to the
GPS subsystem
~ -9dBm
6 OSC IN to UHF PLL
1
2
3
4 5
7
8
6
Dual-band VCO
VCTCXO
UHF PLL IC