INNO3D GTX550IT graphics card heating automatic shutdown repair

Graphics card model: INNO3D GTX550IT graphics card

Malfunction: the graphics card high temperature automatically shuts down.

Maintenance process:

A INNO3D GTX550IT graphics card, which is a fake card.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 1.
Graphics card front

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 2.
Back of graphics card
The video card can be tested, and it can be displayed or driven normally. Running doughnuts, it hasn’t been a minute before you hear the crisp “click” of the power supply Current protection. Unplug auto power off source, unplug 4P VCC of graphics card, and then power it on for testing. It can be turned on. It is preliminarily determined that the core VCC has VCC. Direct measurement of Short circuit G poles on three groups of VCC shows that there are only a dozen Euros, and Short circuit Q538 is directly replaced.The diode value 9.9k Ω is normal. All VCC are tested and the results are as follows:
1. Vddc5v = 5.3v normal
2. Nvvddc = 1.24 V normal
3.MVDDC = 1.69V normal
4.PEX_VDD = 1.19v normal

VCC irst group of c12401 is not running normally, it can be judged tha high temperature does not run normally.When running the doughnut again, it was found that the other two groups of VCC Inductor had no temperature and did not work at all. The resistance of three groups of VCC MOSFET to ground was normal.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 3.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 4.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 5.

The oscilloscope tests three groups of MOSFET g-pole, except the first group q538 g-pole has waveform, the other two groups of upper and lower tube g-pole are not.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 6.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 7.
Detection core VCC chip up1609q, there is no single group and multiple groups of VCC mode switching function, directly change the chip.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 8.

After changing the chip, the waveforms of three groups of upper tube g-pole are normal.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 9.

INNO3D GTX550IT graphics card heating automatic shutdown repair Figure 10.
Run doughnut found that three groups of VCC were high temperature normal, maintenance completed.