PCB(Printed Circuit Board)

When learning how to repair a mobile cell phone, it is important to learn how to identify parts and components on the PCB of a mobile cell phone. Identification of these parts and components is not that difficult.

The PCB of any mobile phone of any brand namely Nokia, Samsung, Motorola, China Mobile Phones etc is divided into 2 Parts namely: (1) Network Section; and (2) Power Section. When identifying parts, electronic components and ICs on the PCB of a mobile cell phone, it is important to keep these two sections in mind.


How to Identify Parts and Components on the PCB of a Mobile Cell Phone:

1. Antenna Point: The point where antenna is connected is called antenna point. It is normally located at the top of the PCB of a mobile phone.

Network Section: The section below antenna point and above power section is called network section.

2. Antenna Switch: It is found in the network section. It is made from metal and non-metal. It has 16 points or legs. In some mobile phones, the antenna switch is merged with PFO.
   

   Antenna Switch of Mobile Phone
3. PFO: Power Frequency Oscillator. It is present beside the antenna switch.
   

   PFO of a Mobile Phone
4. Network IC: It is below or beside the antenna switch and PFO. In some mobile phones, the Network IC is merged with the CPU. E.g.: Nokia 1200, 1650, 1208, 1209 etc.
   

   Network IC of a Mobile Phone

Power Section: This section is below the Network Section.

5. Power IC: In the Power Section, the IC around which there are several brown-colored capacitors is called Power IC. In some mobile phones there are 2 Power ICs.
   

   Power IC of a Mobile Phone
6. CPU: Central Processing Unit. In the power section, the largest IC is the CPU. In some sets there are 2 CPU.
   

   CPU of a Mobile Phone
7. Flash IC: This IC is found beside the CPU.
   

   Flash IC of a Mobile Phone
8. Logic IC: The IC with 20 legs is the Logic IC.
   

   Logic IC of a Mobile Phone
9. Charging IC: In the Power Section, the IC beside R22 is the Charging IC.
   

   Charging IC of a Mobile Phone
10. Audio IC: The IC parallel to Power IC is the Audio IC.
    

    Audio IC of a Mobile Phone

NOTES:

1. UEM (Universal Energy Manager) = Logic IC + Charging IC + Audio IC + Power IC
2. PFO (Power Frequency Oscillator) = Antenna Switch + PFO
3. Flash IC= RAM + Flash IC
   

   Mobile Phone PCB Layout Diagram
4.