Actually, the signal or RF (radio frequency) on all types of mobile phone consists of two major parts, the receiver (RX) and transmit section (tx). Based on experience, damage often occurs in the fractions receiver (RX). If you are experiencing damage to the signal receiver, here I give some tips that I received from various sources.
Damage to the RX section alone there are two types:
1. Low RX
- When looking for a signal manually, we only get one or two networks only.
- The time that we need while browsing no more than four seconds since the signal disappeared.
- Try to replace the antenna switch, or any part of the antenna coupler. Because of this damage is usually not reach the RF ic.
2. No RxCharacteristics: We don’t get any one operator when searching for signals manually.
- Try to check out put from the radio rf (RXi and RXq) using oscilloscope. If still in good condition then the damage must have occurred in IC Audio (usually this section has been merged in the IC Power, DCT4 and WD2 and BB5 are usually combined in the Rap3G).
- Check the working voltage for rf ic, for example vr1, vr2, vr4. If there is something wrong then the damage must have the Power. But can you also do not need to replace IC Power but try using the other voltage value is the same.
- Check tension VCO work if no then replace the power ic or use of other voltage value is the same.
- Check the output VCO (Volt Control Oscillator) using the oscilloscope, a normal or still error? If the error (not normal) then the damage occurred on the VCO.
- Check the tension of the UPP is Sdata, Ssena, Sclock. if no then the damage to the CPU.
- Check the total spending by using the crystal 26Mhz frequency counter. If reduced, the damage occurs in crystal 26mhz / 38Mhz
The conclusion that can be taken is on the receiving end (No RX) because it is caused by IC Power, RF Ic, Crystal 26Mhz/38Mhz, VCO, the CPU.
Discussion then followed on Section TX.
This section also consists of two parts, namely:
- 1. Low TX, Feature: The signal obtained is not good or even falter. Sometimes the signal is there but can not make calls. If this happens, the damage usually occurs in Pa ic (Power Amflifier) and antenna switch.
- No TX, Feature: When looking for a signal manually, we get the three networks at once but when selected show caption "No Access".
- Try checking the output of TX (ie TXi and TXq of audio Ic (UEM / UPP), there is nothing strange if the damage is on Ic Audio.
- Check also Vr2 (Only this voltage is used). If nothing is strange, try to get me another voltage value is the same.
- Check the coupler between the IC and Pa rf.
- Check the working voltage of the PA.
- Check Pa.
- Check the antenna switch.
No Tx can be caused by:
- Ic Audio (UEM/Rap3g)
- Ic Power