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VCORE Processor | Core Voltage for Processor

VCORE Processor | Core Voltage for Processor​

The processor power circuit popularly known as VCORE is also a source controlled by a PWM (Pulse Width Modulation) IC, forming one of the famous switching sources on the motherboard.

In general, this circuit has an average voltage of 1V (remembering that this voltage must be measured with the processor in place and the motherboard connected). There may be a slight variation in this voltage depending on the processor that is attached.

The first valuable tip that I will give you about the VCORE is that in this circuit there is a high current flow, consequently a very low resistance.

But what does that mean? that this low resistance can be easily confused with short.

Take a motherboard from a laptop and with a multimeter on the continuity scale check the resistance of the inductor near the processor (VCORE). It will mark a value between 10ohms to 100ohms at most (some multimeters will give an audible warning).

It is necessary to understand that this resistance above is perfectly normal for this circuit. Different, for example, if you make this same measurement on an inductor in the 3V or 5V circuit that has average resistances between 300ohms to 1000ohms. Important terminals of the IC PWM of the VCORE circuit (it is worth remembering that the supplies of the secondary sources appear after connecting the motherboard)

  • VIN (PWM high power terminal, generally 19V)
  • PVCC or VCC ( power terminal + 5VS )
  • ENABLE or VR_ON ( PWM enabling terminal )
  • PGOOD ( terminal that indicates that the PWM is ok ).

Source Chipset:​

The chipset circuit can be considered one of the best circuits to work with, aside from the fact that it has PONTE NORTE, which is the main responsible for problems in this sector of the motherboard.

HOW DOES CHIPSET PONTE NORTE DEFECT?

The laptops found on the market today are manufactured with a technology called ball grid Array.
This technology known as BGA is the fixation of components (processors, integrated circuits and mainly the North Bridge chipset) on the motherboard through the welding of microspheres.

1651033004791.png

In summary, when this chip has a problem, it needs to be removed from the motherboard (figure 9), exchanged its spheres and redone the fusion with the motherboard through a machine suitable for this type of service. We call this process Reballing.

Reballing is a complex process. How the chip is removed and the balls are exchanged, work inputs are required:

- Correct stencil model (to place the new spheres)
- Soldering station with knife tip (to clean the chip and the motherboard)
- Spheres
- Welding flux
- Desoldering mesh (remove the remaining solder from the motherboard and chip)
- Tweezers.

In addition to other eventual elements that are part of the daily life of those who work with this type of repair.

A practical tip that I can give you in relation to problems with BGA chipset is that depending on the motherboard it pays more to buy a new one. Most popular motherboards on the market cost an average of $ 90.

This value decreases the profit of the service at that moment, however, you will leave a customer very satisfied with a new card in your laptop.
So it is always good to evaluate whether the Reballing process is more cost effective than replacing the motherboard.

Tips: Usually when a laptop is having problems with its Ponte Norte BGA chipset, the symptoms are: screen image failures, laptop does not format and/or has a blue screen, wireless signal does not work.

Chipset Circuit Analysis (VOLTAGE 1.05V)​

Statistically speaking, the 1.05V power supply presents fewer problems compared to the other power supplies on the motherboard. This is one of the last tensions that arise on the motherboard.

It is important to remember that the voltages that supply the PWM ICs of the secondary sources (which only appear after pressing the power button) are generally 5V and/or 3V.

Important terminals to consider in the source PWM IC:

- VDD or VDC (PWM IC power terminal, usually 5V. These names may vary depending on the project in question)
- EN or ON (PWM IC enabling terminal, comes from Super I/O, usually 3V. These names may also vary)
- VREF (PWM IC reference voltage terminal, usually 2V)
- PGOOD (Terminal indicating that the PWM IC is ok, working, usually 3V).

Tip: With all the above voltages ok, the 1.05V voltage should appear on the circuit inductor. If it does not, check if there is a short on the line of this inductor with the multimeter on the continuity scale. Also test the high and low Mosfet’s.

Note: It is worth mentioning that the current consumption of sources such as Chipset and VCORE is very high. This means that the resistance measured on the multimeter in these circuits in relation to the ground is low (between 10 to 100 ohms). Below that, the line is considered to be shorted.
 

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