What is the voltage?

[Life Goes On]

Hi Guys

I need a little help about this hp dv7, when start, it turn on but with black screen, now i try with the schematic LA-9042P to check on the LVDS CONN that evry pin get the right voltage, but on the +LCDVVD and C479 i don't get any voltage and i can't cee what for voltage that has to be neither, can anyone tell me what is the voltage for that, plus the voltage for usb20 P5 and N5,

Hope you guys can help.
[cee picture]

[SteveNielsen]

Re: What is the voltage?

Not sure about +LCDVDD but would be within 3 to 5v depending on what the LCD panel uses, the USB20 P5 and N5 are data i/o + and -, you're not likely to measure any voltage with a meter there.

[Life Goes On]

Re: What is the voltage?

But i have 0 volt on the +LCDVDD, do you have any idea where i can find that right voltage for, and where the voltagre came from in the schematic, cuz i can't find that neither.

[budm]

Re: What is the voltage?

3V 80 milliAmp, It comes from the main board through the switched MOSFET Q43 (P CH). Q144A control the GATE BIAS for Q43, When Gate of Q144A (N CH) is HIGH (VGA_ENVDD, VGA ENABLE SIGNAL), Q43 is ON, when it is LOW, then Q43 is BIAS OFF.

[Life Goes On]

Re: What is the voltage?

3V 80 milliAmp, It comes from the main board through the switched MOSFET Q43 (P CH). Q144A control the GATE BIAS for Q43, When Gate of Q144A (N CH) is HIGH (VGA_ENVDD, VGA ENABLE SIGNAL), Q43 is ON, when it is LOW, then Q43 is BIAS OFF.

But on the 16 VGA_ENVDD and the R276 i don't have any voltage,
what do you think s that ok or not?

[budm]

Re: What is the voltage?

That signal is generated by the mother board, it should go high once the laptop boots up, if not, you will need out the connection in the SCH to see where that control line goes to. It should change state when the laptop is switched between on and off.

[Life Goes On]

Re: What is the voltage?

It come from U5F page 16, take a look, and tell me what you think.

[budm]

Re: What is the voltage?

Do you get all three voltages feeding that U5F?

[atsio]

Re: What is the voltage?

Reflow gpu.

[Life Goes On]

Re: What is the voltage?

Do you get all three voltages feeding that U5F?

Yep all three

[Life Goes On]

Re: What is the voltage?

Reflow gpu.

i did, but did not work.