820-4924 braindead

[arnonabuurs]

Hi Folks, have a 820-4924 that came in today. The board is superclean no liquid. All voltages are there, also 5V_S0. The CPU has 1.05v, but what is missing is 1.8v PPVCC_S0_CPU_REG. I checked U7200, it has on pin 18 0.73v, and on pin 20 and 22 1.96v not sure if that is what it should be? VIN and Enable (0.8v) are there. PPVIN_S0_CPUVR is present on Q7310 and so is the 5V line on pin 6 of U7310 and 7320. I?m not sure how to go about testing what comes out of U7310 and U7320 but it looks like something is wrong here. All looks prestine though. Thoughts?

 

[JohnB8812]

So is PPVCC_S0_CPU 0, 1.05, or 1.8 on the big coils next to the CPU. Any sign of drop damage?

 

[2informaticos]

"VIN and Enable (0.8v) are there."
If you mean CPU_VR_EN, 0.8V is not good.

Do you get 3V at pin 7/U1950?

 

[arnonabuurs]

Hi John L7310 and L7320 have 0V, no signs of hard drops.
At U7200 pin 1 CPU_VR_EN i get 0.78v
At pin 7 from U1950 I get 2.5-2.6v swinging so seems not OK

I measure 2v on PP3V3_S0 which is not good, no short to ground though, i measure 0.522v

 

[arnonabuurs]

I traced it back to U8030, looks like some microscopic corrosion around the IC, will replace it and report back

 

[arnonabuurs]

Fixed, this is exactly why i love to pay for the forum, couldnt have figured this without you guys!!!! Learned something again, makes me wonder how many boards i disposed because I thought the CPU was shorted