Sotay GTX550TI graphics card does not display repair

Sotay GTX550TI graphics card does not display, replaced with BIOS chip, the installation test is normal.

machine model:Sotay GTX550TI

fault phenomenon:the display card does not display

maintenance process:the diode value of getting the display card or playing several groups of VCC is basically normal, and then test several groups of VCC:
1、5V_VDD = 5.2v normal.

Sotay GTX550TI graphics card does not display repair Figure 1.

2、GPU_0 V = 1.

Sotay GTX550TI graphics card does not display repair Figure 2.

MVDD = 1.7V high?I’m not sure, because some video cards have high video memory frequency settings, all VCC and VCC will also be increased. Temporarily test whether the following VCC is normal:

Sotay GTX550TI graphics card does not display repair Figure 3.

4、PCI_VDD = 1.1V normal

Sotay GTX550TI graphics card does not display repair Figure 4.

Several sets of VCC have been tested. In addition to whether the video memory VCC is still to be determined, I directly change the video memory VCC chip up1529q:

Sotay GTX550TI graphics card does not display repair Figure 5.

If VCC is tested again, it is 1.65v, which is a little lower than before, but it still doesn’t show. It seems that the problem may not be caused by VCC. Then test whether the BIOS chip 2 pin has data output, and the oscilloscope test is normal.

Sotay GTX550TI graphics card does not display repair Figure 6.

It indicates that the reset signals are all normal, and CLK is also normal after testing. Please note that when the GPU receives the data signal from BIOS, it will check whether the BIOS data is consistent with the chip. If the data is normal, then read other BIOS setting data,That is to say, there should be a data transmission process between GPU and BIOS 1-2 seconds after the two reset waveforms shown on the oscilloscope. This process should have 1 second signal transmission from the oscilloscope, but I did not have this signal when I tested, indicating that the problem is either the BIOS data problem or the chip itself. Please swipe BIOS first,When I was about to brush the BIOS, I found that the programmer could not recognize the chip. It seems that there is something wrong with the chip itself.