View Single Post
Old 08-18-2020, 06:10 PM   #122
Badcaps Veteran
mockingbird's Avatar
Join Date: Dec 2008
Posts: 5,346
Default Re: [HOWTO] Fix/Repair "Chassis Intruded Fatal Error System Halted" on Asus P5QL

Originally Posted by Th3_uN1Qu3 View Post
There is a dual diode which feeds power to CMOS memory from two places: 5VSB rail of PSU via 3.3V regulator, and the coin cell. You should trace the circuit going from the coin cell holder until you get to that diode. Either the diode is bad or a leaking battery corroded the trace so the battery simply does not get connected to the circuit.
It's been some time, finally making some progress with old projects here...

I found the diode, it tests fine. It comes after a resistor marked 01B (1Kohm) which tests fine. There is a 0.2V forward voltage on both pins.

I think this has more to do with a quirk on some Asus motherboards than it has to do with a defective battery circuit. I only have this problem on my P5PE-VM with a certain CPU installed, and I do have an unsupported CPU (Xeon hack) running in this one, so I might just try it with my Q9650 instead.

My question is: What exactly keeps the SPI alive during a no power state when there is no voltage showing on any of the SPI pins... I tested this on a different motherboard, I installed a battery, and I do not see 3V on the VCC pin of the SPI chip. Unless of course there's supposed to always be 3V on VCC, but I don't remember this other motherboard exhibiting this same issue (Asus P5B).

"...I suppose he wants to be free of youthful associations, as most of us do."
-Robertson Davies

"...don't say oh my god, your god is far away from you. I give you massage. I am your god now."
-Luo Dong
mockingbird is offline   Reply With Quote