Information and Communication Products Communication Devices A lowpass then converts this digital signal to a proportional DC voltage, which is then used to fine tune the TCXO output frequency.
Check the output frequency of the TCXO using the level-2 testing program for S10. Switch off the �CMD in Use� option in the config file (S6xx.CFG or S611.INI depending on the version of the testsoftware) and restart the program. Start the S10 test, when the program says �Check power and phase of external antenna with your GSM-Tester�, switch the CMD to �LOCAL� mode and enter the �MODULE TEST�. On the CMD display you can see the frequency error of the handset. (Make sure that the CMD is on channel 124, power level 5!) If the frequency error is higher than 2kHz, the TCXO has to be replaced.
3.4.1.2Repair by component change
Use hot air blower to remove defective TCXO. Avoid excessive heat! Watch surrounding components! Resolder new TCXO afterwards.
V4.4 Page 9 of 51 ICP CD ST D. Schnoor 11/98
