Pavilion Power Laptop 15-cb quanta-g75c no +VCC_CORE

Hi, this board has problem with +VCC_CORE.

+VCC_CORE is present for a moment when VRON is high, also IMVP_PWRGD is high a few milliseconds.

PU4001 controls +VCC_CORE and other voltage for cpu that are not present either.

There is no short-circuits in any coil going to cpu.

HWPG signa is also present for a moment when the board try to starts.

I think it is because PU4001 is not good, but not sure about it.

I have programmed bios chip but it behaves the same.

IMVP_PWRGD signal seems not to be connected to other circuit. (it seems weird)

Anybody knows about a similar problem with ISL95829?

Thanks.

Hola amigo, supongo que hablas español. No me quedo claro. ¿VRON también se cae, o se mantiene alto todo el tiempo? Saludos

Hi my friend, yes Spanish is my native language, but I will continue to write in English in order to reach more people in the forum.

VRON is high only for a few milliseconds, and then it goes low until I press power button a second time.

All voltage are good during power-on time, except those related to cpu.

NVVDD is also good to power the gpu chip, but also goes down when HWPG goes low.

Most probably ic PU4001 (ISL95829) is causing the problem, but it is possible that other component is altering the power-on sequence.

Thanks for your help.

Ok, I think I can help you. I'm not sure why do you think the ISL95829 is the problem. The sequence in which all happens is very important, and it's not clear to me yet. The ISL95829 would be a suspect if VCC_Core was going down before VRON went down (is that the case?). Even if that is the case, before you can definitely blame the ISL95829, you should also check the SVID signals to make sure is not the processor who is telling the ISL95829 to shut down VCC_Core. But let’s go one step at a time and clarify the order in which everything happens first.
Also, you said that IMVP_PWRGD is not connected anywhere. But in the schematic(.png) you attached IMVP_PWRGD does go somewhere else. Unless that is not from the actual schematic of your Motherboard. If you don’t have the actual schematic, you should get it (viewtopic.php?f=250&t=1393&start=1160).

***También puedes enviarme (raydelb612@gmail.com) dicho esquema completo para que pueda ayudarte más fácilmente (soy nuevo en este foro y no me sobran los puntos), o subirlo aquí en un .rar (aunque no estoy seguro de que esta segunda opción sea legal en este foro). Saludos***

Hi, Raydel87, i have found a short circuit in one of the ic that drive the vcore mosfets. The ic ISL95808HRZ-T (PU4005) has a very low resistance at the LGATE1_B pin, and there are other ISL95808HRZ-T that have weird readings in its pins.

Y have ordered some of this chips to replace the bad chips, and I hope the cpu itself are not damaged. (there are no shorts in the coils that are connected to the cpu, 2 ohms are low but this is a powerful cpu, so I think it is normal)

About IMVP_PWRGD signal, it's weird also, but searching "IMVP_PWRGD" across pdf file does not show any results, only that near the ISL95829.

I will post the good news when replaced the damaged chips.

Thanks.