PS1/2 PS2 Slim not showing Video, Audio, only green led

[MegaGenesis]

Hi. A few weeks ago my PlayStation 2 Slim (model NTSC-J 90006) stopped working out of nowhere. It just turned off on its own and it never worked again. StandBy light comes, and pressing power shows the green led, but the consoles gives no sign of life: No Video, No Audio, Disk doesn't spin, fan doesn't spin. The think was 12 years old and never had any issues before, so i sent it to a technician. After the evaluation he told the console's motherboard was "too rusty", therefore there was no fix. He offered to replace the mobo, but the price was higher than a second hand PS2 with original controllers, MCs and games. I said no and got my PS2 back.

Since the console was dead, i opened it to give a look, but to my surprise there is not signs of rusting anywhere, Aside from collected dust, there was no signs of rusted eletronics, no opened capacitors, the modchip looks fine, the power supply looks in good shape to me, no cut cables. Does anyone here know what issue could it be? I want to test the PSU, but i don't know how to use a multimeter. The multimeter i have it this yellow one in the photos.

Motherboard model is GH-070-42. Modchip is Matrix Infinity v1.93.

Now i'm almost sure the technician never fully opened my PS2 for inspection. For some reason, my PS2 is slight different from other 9000x models i saw online, mine was harder to dissassemble.

 

[DobaMuffin]

If possible, could you take closer pictures of various parts of the motherboard. It would just help a little more in seeing if anything could be wrong. The next step would also be to check the psu where it connects to the motherboard. You would set it to voltage mode and touch the black probe to the copper around the edge of the motherboard. The red probe would go to the 2 solder points right next to the connector on the motherboard.

EDIT: Also that doesn't look like rust, just a dusty motherboard. I recently got a 90001 with lots of rust and corrosion. You symptoms sound like the psu might have failed in some way, but I'm not 100% sure about that.