Dell Inspiron 15 3542 (FX3MC13269-1UMA) Gray Screen Repair

Laptop Model: Dell Inspiron 15 3542

Board Number: FX3MC 13269-1 UMA

Fault: Gray Screen After Entering The Desktop

Repair Process:

 

Troubleshoot the system, screen, and memory in order to lock the fault in the motherboard. After disassembling the machine, it was found that the machine has an integrated graphics motherboard and an onboard CPU. 

 

After flashing the BIOS to no avail, the general goal is to focus on memory power supply and CPU integrated graphics power supply. First check the memory power supply.

When looking at the chip model, we found that there are signs of corrosion on several resistors and capacitors on the upper part of the memory power supply IC TPS51716.

 

Looking at the drawing, I found that they are R4903 and PC4903 connected to 6-pin VREF and PC4902 and PR4901 connected to 8-pin VREFIN.

I first roughly measured the resistance of the two resistors online. PR4903 is about 10K and PR4901 is about 100K. It is obviously the same as the figure.

The 30K resistor on the resistor is too large. I flipped through the material board for a long time to find a 30K resistor and replaced it. Then I started the system and everything was normal.

The fault was originally a minor problem. Because this fault point was encountered for the first time, I checked the TPS51716 data sheet after the customer left:

 

　　The original text of 6-pin VREF is: 1.8-Vreference output. (1.8V REF output)

　　The original text of 8-pin VREFIN is: Reference input for VDDQ. Connect to the midpoint of a resistor divider from VREF to GND. Add a Capacitor for stable operation. (Reference input of VDDQ, connect to resistor divider from VREF to GND, add a capacitor for stable operation.)

VDDQ is actually the memory power supply. This fault should be caused by inaccurate memory power supply, causing the memory to work abnormally.

The memory of the integrated display machine is also used as video memory, so it causes a gray screen failure when entering the system. At first, because the machine can light up, the major power supplies are not measured. If it is measured the repair time is estimated to be less.

 Happy Repairing !!