Nokia E72 No Network Signal Problem Solution

Here's the solution for Nokia E72 handset  with no network signal problem.

If ever tried to fix network problem on E72, you must first restore, update the the device flash firmware before do a hardware repair attempt.
If the flash firmware calibration does not solved and fix the problem, you may then proceed to hardware troubleshooting.
The solution below shows the RF circuit (radio frequency) of Nokia E72 PCB board layout, and being labeled to easily determine which part needs to check first or replace and so on.

Nokia E72 No Network Signal Solution
nokia e72 no dropping signal problem repair picture

In troubleshooting RF signal problem you may need to have a frequency counter to make it easy to repair, but you may also fix it by doing it manually.
First, check the all supply voltages that feeds to each of the RF circuit chips like the RF power amplifier and RF IC.

There is an RF power supply controller that also feeds the secondary supply other than the battery supply voltage of 3.7 volts.
You can check it trough the filter coils., If these supply voltages are missing it means that the RF power management IC is faulty. Rework or replace it if necessary.

If all the supply voltage is okay, check the RF clock oscillator or try to replace it.

If the clock oscillator is okay, rework the RF Power Amplifier (PA) replace if necessary.

The RF IC will be the last chips needs to rework or replace for further troubleshooting.