Sotay geforce RTX 2060 super-8gd6 graphics card full board VCC repair

Sotay geforce RTX 2060 super-8gd6 graphics card full board VCC repair.

the whole board of sotay geforce RTX 2060 super-8gd6 graphics card is not VCC, the fan starts to run wildly, does not recognize the card, installs the radiator graphics card, the computer operates normally, troubleshooting!

Machine model: sotay geforce RTX 2060 super-8gd6
Fault phenomenon: the fan is running wildly and the card is not recognized.
Maintenance process:When the radiator was removed, only 5V VCC produced 1.8V, but 1.8V did not generate normally, resulting in the subsequent VCC not producing and the measured 1.8V en did not produce.Finally, we find that PS is PS_vmon_PGOOD signal did not rise, and it was confirmed that it was BS of on45491_If ok is not generated normally, the whole board is not reset and replaced directly, and the fault is still the same.

After finding PDF, it is found that this is a high-performance 4 Related circuit current and VCC monitoring chip of ansomer, which can output the monitoring results to the external ADC through a group of check signals, and intercept a simple application block diagram first.

Sotay geforce RTX 2060 super-8gd6 graphics card full board VCC repair Figure 1.

It is not difficult to see BS from the diagram_If ok wants to output high, the conditions involved are very simple, as long as BS_INX (X represents 4 channel numbers) is higher than BS_At the same time, the logical output of BS. Ref should be correct_OK, so we immediately found BS_The text description part of OK.

Sotay geforce RTX 2060 super-8gd6 graphics card full board VCC repair Figure 2.

BS_OK describes BS_INX valid signal, when BS_When INX is not within the acceptable range, BS_OK remains low until BS_INX qualified, BS_The effective condition of INX is that it must be higher than BS_Ref VCC and BS_Ref VCC cannot be higher than 0.2V BS_OK is controlled by skip logic. Skip can lock BS when there is no VCC access_OK is low, when skip is 0V, BS_INX shape State is ignored.

Sotay geforce RTX 2060 super-8gd6 graphics card full board VCC repair Figure 3.

Understand these, we can analyze the specific application of graphics card drawings, or start from the drawing analysis, first look at the key BS diagram_How is ref produced.

Sotay geforce RTX 2060 super-8gd6 graphics card full board VCC repair Figure 4.

In BS_When OK output is high, BS_For rb572 and r582_REF_Out partial pressure, BG given in the manual_REF_The minimum out value should not be less than 1.274v, and the maximum value should not be higher than 1.326v. The standard value is 1.3V.With the data, we will calculate BS according to the standard value_What V is ref.BS_REF=（10K/10K+90.9K）*1.3V=0.128V.

This is in BS_OK has no BS when the output is high_As can be seen from the figure, one is BS_OK output is high, q503 will be on, r584 will be in parallel with r572, and BS_Ref is equal to BS_Ref (bs_ok = h) = (90.9k / / 10K) / (90.9k / / 10K + 90.9k) * 1.3V = (9.01k/9.01k + 90.9k) * 1.3V = 0.117v.
When BS_When OK is high, BS will be reduced by parallel connection of r584 and r572__Partial pressure value of Ref.To BS_INX has a wider range of fluctuations.

Sotay geforce RTX 2060 super-8gd6 graphics card full board VCC repair Figure 5.

BS in the figure_IN1 BS_IN2 BS_The input of diode value is the same as that of diode value, so the input of Connect the power supply v is the same as that of Connect the power supply_In (123 equal) but BS_In4 is a 3.3V monitoring BS_In (123) = (1K / 1K + 75K) * 12V = 0.157v,BS_If ref is 0.128v, 12V minimum input VCC threshold value should not be lower than 9.728v,BS_IN4=（1K/1k+19.6k)*3.3=0.160V,By BS_If ref is 0.128v, 3.3 minimum input VCC threshold value should not be lower than 2.63V,According to the drawing reasoning can be appropriate BS_BS when OK is not high_INX>BS_Ref normal BS_OK is sure to output for OD, because the external pull-up, so it should be high.

The main conditions for the physical measurement immediately are VCC = 3.1V and skip = 5V_INX must be greater than BS_REF BS_If it is OK, it will be high_All inx123 are 0.159v BS_When in4 is 0.164v, the BS is within the acceptable range_Ref is 0.153v.Is it not Tao or BS_INX is only better than BS_Ref high 0.006v does not enter BS_The minimum output range of OK.

But BG_REF_29 V, normal.This is strange, how the partial pressure value is on the high side, 90.9k and 10K are also normal.

In order to repair quickly, the BS_The upper partial pressure of in123 is changed to 68K (this diode value is easy to find).Increase and BS_The pressure difference of ref, BS was found on power on_OK is 0.8V, oscillograph is found to be a 3V continuous pulse charging, regardless of BS_OK raised, according to the analysis of BS_Ref should be reduced to 0.11v.But a test of BS_Ref is still 0.153v.It shows that q503 is not connected. The power is cut off immediately to measure q503. When Open circuit and SMD REWORK STATION are blown off between be poles, it is found that e pole is left on PAD, which should be caused by collision.Replace a 3904 right nowtriodeGo up, measure BS at power on_OK has been high level 3.1V BS_Ref also fell to 0.11v and skip was pulled down by external q519.At this time, BS_INX should be ignored by skip logic.This indicates that the power monitoring of the display card only detects bus VCC before power on.BS, etc_After OK, there is no need to detect BS_INX state, after power on or to monitor the current, to understand the real-time power of the graphics card, installed radiator graphics card has been successfully lit, run a test program, all OK, troubleshooting!