Please note before you may use this solution, first ensure that the device firmware is totally calibrated, successfully flashed or restored and upgraded or downgraded. This solution below covers only for hardware failure that may not or can't be fix by software or firmware.
The Nokia 7230 RF circuit components mounting is similar to Nokia X6. This solution below is from Nokia X6 board.
Nokia 7230 No Network Signal Solution
Just follow the instructions indicated on the solution above of which and where to start in troubleshooting proceedings. In most common cases the RF Power Amplifier breakdown may most often causes the problem.