Mobile Phone Signal Is Lost

Problem: When you insert a SIM card and turn on the phone, then there is no signal or network appears on the phone LCD.

Repair procedure:

• Check the first component of the antenna and antenna connector, make sure the well connected. Especially when your phone is a phone with an internal antenna, associated with the PCB or motherboard via two pointers elastic contact, if the contact is experiencing a second pointer contact the ugly, the problem that arises is the absence of a network (no network) and a bad signal reception even signal lost (no signal). Especially with the engine knock or fall into the water, a bad contact and oxidation will occur at the contact pointer. The antenna switch is the only way to rnenerima and send a signal, if it is damaged or faulty soldering of the pin, it would appear the problem is not the network or transmission
• Next we try to find the network on the phone with the manual method, if the method fails in this manual search for a network, so we can make sure there is a problem in the RF IC (HAGAR), change the RF IC (HAGAR) is then the problem will be completed
• Networks can be searched by manual method but sometimes fail, not even able to connect well with the network. This phenomenon is due to issue the RF IC (HAGAR), IC AUDIO (COBBA). If the module COBBA show any error, most likely was caused by his BGA soldering and units around the poor, or lack of flow, while most issues HAGAR its units due to poor
• If looking for a network with manual methods on our cell phones only get 1 (one) operator / service provider cellular only, then there is a problem with the IC VCO, VCO IC replace it then the problem will be completed
• If there is no problem with the manual method, check the current flow from the battery to the IC PA, if there is no problem with the next line we check whether the PA IC components function properly. We could use a multitester to test IC PA, IC PA if it is not functioning properly, we replace the IC PA is then the problem will be completed
• After testing and improvements in hardware we did but still no signal / lost, then we will continue with the software. We flash phones according to the types of phones and phone software version before or with the newer software version (upgrade)

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