Acer Aspire 5530G strange display behaviour

[Retrocomputer]

Hi everybody!
I have an Acer Aspire 5530G (LA-4171P) with discrete graphics. The original MXM card (ati HD 3470) was used to revive another pc some time ago. I have a nVidia MXM (8400M gs iirc) card from the 17" acer brother, it has some issues but it was correctly showing on screen albeit with some artifacts. If i try turning it on with the card installed it shows a black screen with leds on and fans spinning after some short time. If I turn it on without the discrete card in (it should use the internal one) it boots to a completely white screen. What can it be? Already tried flashing a fresh BIOS copy.
If you need anything, ask me!

Here the schematics.

Thank you!

[piernov]

Re: Acer Aspire 5530G strange display behaviour

NVidia 8400M GS is obviously dead.

[Retrocomputer]

Re: Acer Aspire 5530G strange display behaviour

Yep, I thought the same. But why a white screen with no discrete card installed? The IGP (radeon RS780M) should work anyway, or am I wrong?

[Retrocomputer]

Re: Acer Aspire 5530G strange display behaviour

Judging from the block diagram, at least, the LCD is driven both by the MXM interface card or directly from the IGP, so it should show something...
Thank you so much again!

[piernov]

Re: Acer Aspire 5530G strange display behaviour

It may not be enabled (or usable at all) if the laptop was configured with a dedicated graphics card from factory.

EDIT: looking at the schematics, it is either configured for UMA (integrated graphics) or VGA (dedicated graphics) only. Converting from one to the other at least requires exchanging a lot of parts.