detailed explanation for failure VGA cards

1.No display and blank screen when booting  

This kind of failure is always caused by bad contact between VGA card and mainboard, or bad mainboard slot. As for this, clean it is ok.

The mainboard would produce a long and two short noise if the failure of no display caused by VGA card

If the failure is caused by VGA card, we could judge from following:  

(1)Measure the supply voltage of VGA card: such as VDD PLVDD VDD_CT 3.3V 5V 12V etc.

(2)Read the BIOS data to make sure if the data lost.

(3)Measure the 0.1 uf capacitance beside gold finger of PCIE signals, confirm if it is good or not

(4)Measure the resistance of gold finger of PCIE signals, confirm if the GPU is good or not

(5)Measure the signals of HSYNC VSYNC, confirm if the GPU is good or not。

2.Display as color aberration

The reasons of this kind failure are always as following:

(1). Bad contact between display card and the display signal line;

(2). Display itself is bad;

(3). Color aberration in some software generally appear in the old style computer, there is an option for checking color in the BIOS, open it is ok;

(4).The display is magnetized, this kind of phenomenon is generally caused by too near with the magnetic object, it may also cause image deflexion after magnetization;

(5). Damage of VGA card can judge from the followings:

u        Make sure if there is any crack in output part of VGA card

u        Measure the resistance of R G B signal to confirm if it is 75 Ω

3.Hang up when enter system

This kind of failure always appear as following: the mainboard and VGA cards are not compatible, or bad contact between mainboard and VGA card. But there is individual phenomenon, that is VGA card and other expand cards are not compatible;Moreover, wrong installation of drive maybe also the cause.

4.Bad screen in windows system

This kind of failure is always caused by nonsupport of high distinguish rate of display and VGA card, we can switch start mode to security mode after bad screen, then enter display setting in the windows, choose the “apply” and “ok” button under 16 color state, reboot the computer, delete driver under windows normal mode, reboot the computer then.

If we do not enter security mode, we can also edit document “system.ini”, change display.drv=the pnpdrver to display.drv=the vga.drv, save and exit, update driver under windows and then solve immediately.

5.Character and image display incompletely appear in the windows

Solution is the same as bad screen, if the image is clear, just delete driver, then reboot computer, install driver could solve immediately.

6.Abnormal stripe or irregular patterns appear when booting

This kind of failure is always caused by bad contact between VGA card and mainboard, clean the gold finger; If it is caused by bad memory, then just change the VGA card, it could be judged by measuring voltage and resistance of memory(FBVDD)

7.After installing driver, the driver lost automatically after running a period of time

This kind of failure is always caused by incompatible mainboard and VGA card, which result in instable running and hang up, it could be solved by changing VGA card. There is another special phenomenon, that is after the driver installed, hang up would appear when entering windows. As for this, change other type VGA card first, then install the driver, reinsert the former card could be solved; if it is also failed, it may be the problem of registration form, recovering or re- installing operate system could be solved.

8.Bad screen in some special software

This kind of phenomenon is generally result from the software edition which is too old to support the new style cards, or the card itself is bad, try to replace drive if it does not match.