LA-8241P DELL, short circuit ?

[warsztat]

Hello, my problem it possible short circuit in the region GPU.
I have a diagram but i do not have board view.
This short circuit occurs at everyone RAM GPU, i suspect there is power but maybe i'm wrong but occurs there 0 ohms. (sorry my bad english)

Foto :

[khaahk]

Re: LA-8241P DELL, short circuit ?

If 0 ohms, use lab PSU to find short.

[warsztat]

Re: LA-8241P DELL, short circuit ?

Thank you for your answer. It will be a last resort. I am looking for info mark capacitor on the schematic.

[BlueMidnight]

Re: LA-8241P DELL, short circuit ?

Ohm's Law: Voltage = Current x Resistance

For some components (e.g. the CPU and GPU), their power rails will show a very small (less than 1 ohm) resistance. This is because they operate on a very low voltage and draw a large current. Small voltage / Big current = Small resistance.

You did not say exactly what the symptoms are. But you might want to plug in the board and measure voltages on the power rails instead.

[warsztat]

Re: LA-8241P DELL, short circuit ?

GPU removed. Still 0 ohm. No short circuits on the GPU / RAM power converter.
I need board view or info.

[khaahk]

Re: LA-8241P DELL, short circuit ?

Why is using lab psu to find short your last resort? If no boardview available then it should be the next move.
If the capacitor is on the memory power line then short should also be on buck converter chip output and parallel to a lot of other capacitors. What help do you get from boardview in this situation?

[warsztat]

Re: LA-8241P DELL, short circuit ?

My worked out procedure. Current I would like to give from the power side and I do not know if there is a key on this line and is this line.

[warsztat]

Re: LA-8241P DELL, short circuit ?

I found some time for this case. I find short circuit, it was not a broken capacitor. The short circuit was under VRAM, melted balls bga. I measured measurement points on connections to the GPU that was weird, because my english is bad I attach the photo.

Lab PSU to find short did not help in this case.
Someone warm up GPU moved UV24. I'm another person trying to fix.
Currently all system on site, board takes ~1-1,2 Amp, the system speaker makes regular short squeals not screen on lcd.
I do not know the error code, GPU broken ?

[coolwiz computers]

Re: LA-8241P DELL, short circuit ?

if you have another GPU YOU CAN CHANGE IT OR YOU RECHECK MAYBE A POWER MOSFET IS CAUSING THE SHORT

[warsztat]

Re: LA-8241P DELL, short circuit ?

Power on VRAM 1,5V , power mosfet ok. I was programming bios, bios from dell 5520 = 5 beep, bios another one dell vostro 3560 (this laptop) = 1 beep per 2-3sek. I do not have others bios this motherboard. Maybe change GPU.

[spleenharvester]

Re: LA-8241P DELL, short circuit ?

According to internet sources you can convert these boards from dis to UMA simply by removing PL800. Is it maybe worth testing without PL800 if you are unsure whether it is a GPU problem?

It's also worth noting these boards will not POST unless there is an LVDS/screen connection present, even to an external display.

Also 5 beeps can be CMOS battery issue

[warsztat]

Re: LA-8241P DELL, short circuit ?

Battery cmos ok, i think bios wrong this board (5520 > 3560), no screen on external monitor unless LVDS connector, beep still is it.
First advice (removing PL800) not known to me, maybe i try how I find time. Thank You.

[warsztat]

Re: LA-8241P DELL, short circuit ?

The laptop owner resigned from the repair, thank's all.