Learn IC Line Series and Parallel Electronic Components Fault Tracing

The article helps you to find the fault in mobile phone PCB by reading and following it thoroughly you will be able to check the electronics components in the series and parallel line of any IC. You will be able to check the IC by recognizing it and finding out whether the IC is bad or not. The blog post also helps fully find the boot capacitors with the help of a mobile schematic diagram.

What Is LUB Graphic IC Which Mobile Company Is Using It?

LUB Graphic IC is a type of integrated circuit that is mostly used in smartphone PCBs and other electronic devices. LUB stands for "Low Cost Unified Bus Graphics Integrated Circuit" and is designed to provide high-performance graphics capabilities at a lower cost than the graphics processors. Most smartphone companies, including Infinix, Tecno, Oppo, Samsung, and Vivo, use this IC as a graphic display IC in their smartphone PCB. When repairing smartphones, ensure to check this IC if there is no graphic fault on the phone's LCD. This IC can be tested using a four-digit digital multimeter.

Learn Fault Finding in IC Series and Parallel lines

Learn what GR reading is, and how to check it with the digital multimeter on an LCD Connector before testing LUB IC read the article Common LCD Connector GR Reading of the Mobile PCB

Checking LUB Graphic IC in Mobile Phone PCB with Digital Multimeter

1. Set the digital multimeter to diode mode. 
2. Connect the red probe to the ground and the black to the VSP capacitor near the LUB IC. It shows the 300 to 600 GR reading.
3. Connect the red probe to the ground and the black to the VSN capacitor near the LUB IC. It shows an OL reading. 

Note: if the LUB IC is short circuit, then it shows a GR reading from the VSN supply line.

Lub IC Checking tips

While repairing the LCD graphic fault, if we find that the LUB IC is okay, then after checking the IC, we need to inspect the boot capacitor in the series line from the supply lines of the IC. Now we tell you how to find a boot capacitor in a mobile PCB with the help of a mobile schematic diagram.

Learn what a boot capacitor is, and how to read a mobile schematic diagram before finding a fault in the mobile phone's PCB

Finding Boot Capacitor In Series Line of LUB IC

Follow the steps below to find the boot capacitor in the smartphone PCB:

• Open the mobile schematic diagram then find LUB Graphic IC by typing its number taken from the component layout diagram. Then see the CFLY 1 and CFLY 2 line in and out from the IC. This line capacitor is a boot capacitor.
• First, check the capacitor reverse biasing reading and then the forward biasing reading at diode mode with a digital multimeter to confirm that it is connected to the Graphic IC.

You can use this method in Infinix, Tecno, Oppo, and Vivo, other smartphone companies, phone PCBs that is using LUB IC.

Why Electronic Components Are Installed In The Series Supply Line Of The IC?

The series component is used to filter and resist the voltage in the IC Supply line. If there is a fault in the line, then the series electronic component is necessary to check with a multimeter. If the component is not working, then put something in its place. Otherwise, the current will remain here and it will not go ahead. The IC circuit is never on if the series component is faulty.

 

Series Electronic Components

If you want to learn about the mobile phone's electronic components on the mobile PCB, you can read our article on all electronic components' names and pictures

Why Is Parallel Electronic Component Installed?

The parallel component is used to stabilize the voltage in the line. If the line has a short circuit, then the parallel electronic component is necessary to check with a multimeter. If the component is not working, then remove it from the line. it is better to place the new component in its place. Otherwise, switching voltage in the line can cause damage to the integrated circuit. in many case studies, we found that integrated circuits have short circuits due to faulty parallel components. Now let's teach you to identify the series and parallel components of mobile phone with the help of the Hardware Solution Diagram in the schematic tool.

Series and Parallel Components Dots in The Hardware Solution Diagram

Series and parallel component diagram

In the hardware solution diagram, the red line touches the electronic parts with two Dots.

1. One side Dot at the electronic component.
2. Two side Dots at the electronic component.

One side Dot at the electronic component: when in the diagram if the line touches the component one side with one dot then it is the series electronic component.

 

Parallel and Series Component Symbol

 

Two side Dots at the electronic component: when in the diagram if the line touches the component on both sides with a dot then it is the parallel electronic component.

 

Series and Parallel Component identify

Conclusion: By understanding and mastering the techniques of IC Line Series and Parallel Electronic Components Fault Tracing, you are now equipped with the knowledge and skills to troubleshoot electronic components and ICs effectively. Learning about the LUB Graphic IC and Boot Capacitor in the mobile PCB, as well as finding and testing series and parallel components, has now enhanced your ability to diagnose and fix hardware issues in the smartphone.