GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair

Graphics card model: Galaxy GTX750 Primitive (2GD5 core)

Malfunction: boot into the desktop and install the driver monitor screen is black or frozen.

Maintenance process:

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 1.

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 2.

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 3.
A Galaxy GTX750 Primitive graphics card can enter the desktop at the beginning of the failure. When installing the driver,screen is black or frozen is used. All VCC except PEX _ 12PEX _ 3.3V and VDDC_5V are normal. Other VCC are 0V, which is preliminarily determined to be the core VCC problem.

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 4.
No missing parts were found during the appearance inspection. The auto power off problem is usually the core problem, and the other is the EN EN problem. Test all VCC,VCC timing: ① vddc _ 5v → ② nvvddc → ③ mvddc → ④ PEX _ vdd.

⑷ The measured value of ⒈VDDC_5V is 5.13V normal;

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 5.

1. it is normal that ⒉NVVDDC measured value is 1.03V;

3. The measured value of ⒊MVDDC is 1.56V, which is also normal;

⑷ ⒋PEX_VDD: It is normal for this graphics card and VCC to be separated into two groups.

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 6.

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 7.

Re-test the U6 print of the core VCC chip with 0T=1C: the chip with RT8811AGQW. See the chip data.

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 8.

1 pin is 5V,21 pin is 12V,VCC tests are all normal, and test 3 pin EN pin is always 2.3V high level. The problem of replacing the chip directly remains the same. Eliminate the places that may affect this kind of faults one by one, and first replace several groups of VCC Capacitor.

GALAXY gtx750 will install the graphics card to drive the black screen of the display for repair Figure 9.
It’s the same with BIOS. Referring to schematic, we checked that the peripheral components of the chip were eliminated one by one. When we found 9 pin, we found that this video card PCBA has a pull-up 50K resistor, other 52K resistors and a Capacitor of 0.1UF, because this pin is an on/time frequency setting pin, and that Capacitor should be oscillating.If not, then VCC chip can’t work properly.