820-00165-A "H2O Basket Case" Pulls 0.165 mA Is in a S0 state does not boot

[KC Micro Tronix]

820-00165-A "H2O Basket Case" Pulls 0.165 mA Is in a S0 state does not boot

I have been digging through my trash pile to learn today. Now i am working on a 820-00165-A that had water damage all over. Luckily I have not had to do trace repair. I know the back light section trashed. I don't want to waste time on the back light unless I get it to boot. I have had to replace a few shorted caps. Now I have a MagSafe light and all my rails are up!

Now the board is in a S0 State with (All S0 rails up!)

Normally during a boot cycle when watching thermal imaging U3900 fires up followed shortly by the memory modules and CPU. I am not getting the normal memory module warming or CPU warming. The CPU does warm slightly but obviously it is doing nothing.

Looking around on the memory "I did check all the voltages on the modules and all test good!" I noticed that MEM_B_CLK_N<1> is not present. I then checked the CPU SUS clocks. Nice square waves. Bios has power. I went directly to all the clocks. All are present.

It kind of looks like a bios issue. The voltages are present and clocks are present.

I would appreciate some guidance on what I should check. Seems like I am in a digital side of the house and just not sure what to look at.

 

[2informaticos]

Sometime corroded boards end with bad BIOS.
You can find few clean dumps for test on the forum...

 

[KC Micro Tronix]

New Bios did not solve my problem

I flashed it with a known good from one of my working boards. (I saved the original first).
They were the exact same part number and CPU / Ram. When analyzing the ME they were the same version. I wiped the ME from the known working bios and loaded a clean version and loaded it onto the board.

I am still having the same problem. No activity and pulling 0.175 mA. This must be a mechanical problem or another damaged part. I just don't know what to check in data land.

How can you tell the CPU is actually going out to the bios and reading it?
Is there anything I can read on this?

( I have to put the toy box away and get to real work. I am have lots of work piled up that has to go out Monday ) No rush on the reply.
Thanks for your help this weekend 2informaticos.

 

[2informaticos]

Do not clean ME of backup.
That doesn't help when main BIOS is corrupted.
You must try known good full BIOS file.
On the forum we have few, including clean ME.

Be sure all SPI Bus Series Termination resistors are good; patience, are more than 20.
Also check all traces for these resistors and SPI chip.

 

[KC Micro Tronix]

Will do. It will be next week before I get back to this board.
FWIW I did use a working bios not the one on the board. I didn't simply clean the ME. I cleaned the ME on a working copy from another board and flashed that one on to this board.