Signal repair procedure

When we insert SIM card then on the handphone, there is no signal or network that appear in handphone LCD.lets try this repair procedure:

• Investigate the antenna component and antenna connector, make sure linked well. Even your handphone using inside antenna, relating to PCB or mainboard that pass two elastic contact pointers, if both are bad contact, the problem is no network and bad signal receiving then lost (no signal). Especially the machine that bumped or drop into water, the bad contact and oxidation will happen in contact pointer. Antenna switch is only way to receive and transmit signal, if broken or broken soldering pin, will cause no network or transmission.
• Furthermore we try to search network in handphone manually, if it fail againt, it means there is problem in RF IC (HAGAR), so change RF IC (HAGAR).
• Network can be looked for with manual method but Sometimes fail, Even can not linked with the network. This is caused IC RF's problem (HAGAR), IC Audio (COBBA). If COBBA's module shows error, The possibility caused of BGA's soldering and bad units, or Current deficit. But usually HAGAR's problem caused by bad unit.
• If look for network with manual method only gets 1 (one) operator/provide cellular service service, So there problem in IC VCO, Change this VCO IC so problem finished
• If there is no problem with manual method, Investigate stripe from battery to IC PA, if there is no problem with stripe, investigating that IC PA's component functioneds well. We can use multitester to test IC PA, If IC PA doesn't functioned well, We shall change this IC PA so problem finished.
• If Hadware testing and Repair have been done but signal still fluctuates, So check the software. Flash handphone as according as kind of handphone and Previous handphone software version or with the latest software version (upgrade)