identificationsurface-mountvga
I did clean my VGA adapter MSI Geforce gtx 1070 with compressed air and one smd component has gone, now the adapter did not work. On another adapter I found out the marking on the component body and it is just – VT. I have no idea what is this. Could somebody help to find out what is this. On the PCB it is marked as U506.
After googling the code 5393 I stumbled across this datasheet. The component appears to be the Toshiba TA75393F, and for me it matches your schematic perfectly.
It seems like you're using the 7.15V reference to detect the presence of the 380VDC, in fact this reference is hooked to the "-" pin of the comparator, and in the case of the comparator B, once the reference disappears, the output goes to low making the PNP transistor conducting.
On the other side, the comparator A with the positive feedback branch makes me think of a comparator with hysteresis. According to this question it could be an overvoltage detection circuit (and in this case the higher external reference would make sense since you want to trigger your comparator only in the case when the 380VDC source has an overvoltage).
Your U10 is a Microchip 24FC256 - spot the logo in the pin-4 corner?
I suspect that your U9 might be a Linear technology LTC1663.
The pin connections for VCC(pin-4) and GND(pin-2) are almost certainly correct, making C46 its decoupling cap.
Best Answer
It could be a 74LVC1G80 Single D-type flip-flop.
From page 2 of the linked Nexperia datasheet
Not sure which package - it's either TSSOP5(SOT535-1) or SC-74A(SOT753). You'll have to check the dimension of the package and/or pin pitch.
The TSSOP5 package is about 2mm wide with a pitch of 0.65mm while the SC-74A is about 3mm wide with a pitch of almost 1mm.