BIOS POST card error EE D0 AMI bios Lenovo mobo - Page 1
Forum section: electronics / beginners

author: poot36
author_rank: Frequent Contributor
timestamp: March 08, 2015, 12:34:38 am
content: I have a Lenovo AMD Athalon X2 motherboard (model L-A690) with a AMI 686 bios in it that wont boot but a POST card says EE D0. This does not change if I have ram in the system or not. If I short out the BIOS programming header pins the POST card stays at ---- (four dashes on a 4 by 8 segment display) so I know the processor is working. Also a small voltage regulator gets hot (U35 L1087G) near the sound chip (ALC888 realtek). <-- (EDIT This is due to a damaged sound chip, the chip has been removed and the regulator does not get hot and outputs 5V. No change on POST card error.) The regulator has 12V coming in, 5V or so on the adjust pin and 3.29V on the output. There is a cap and diode near the regulator that show under 5 ohms of resistance so I wonder if this is part of the problem. I have already replaced another bulging cap near the ATI Radeon Xpress chipset (Northbridge I think?) on a 1.8V rail showing 1.78V.

author: cpt.charlie
author_rank: Contributor
timestamp: March 08, 2015, 11:45:04 pm
content: If you suspect of a shorted component, you may detect the faulty component by injecting in the circuit a low voltage (1V at limited current like 500mA) and measuring the temperature in nearby components, sometimes the decoupling cap has failed.

author: poot36
author_rank: Frequent Contributor
timestamp: March 15, 2015, 11:09:07 pm
content: Well I removed the cap and now it is showing 14 ohms between the removed caps terminals. However the regulator still gets very hot and now the sound card chip is also getting warm. I have not yet replaced the cap yet with a working one. Is it possible that a fried sound card chip could cause the computer to not start up? I could remove the sound card chip if necessary.

author: cpt.charlie
author_rank: Contributor
timestamp: March 15, 2015, 11:34:59 pm
content: If you check the removed cap out of the circuit, was it shorted?

author: poot36
author_rank: Frequent Contributor
timestamp: March 16, 2015, 12:07:13 am
content: Sadly I can't due to one of the legs of the cap staying in the board when I was trying to remove it. Although the ohm reading did increase from 4 to 6 ohms to the aforementioned 14 ohms after I removed it so it probably was part of the problem. I think the whole problem may have started when I was trying to measure the regulator and my probe slipped and could have caused the 12V rail to connect to the 5V or so adjust pin on the regulator or the 5V or so adjust pin to the 3.3V output of the regulator. I am not sure about this though. Would the resistor divider powered adjust pin have enough current to damage the 3.3V parts or not? I am not sure what the regulator would put out if the adjust pin was taken to the 12V rail. If the sound card chip is damaged could this cause the motherboard not to boot?

author: poot36
author_rank: Frequent Contributor
timestamp: April 07, 2015, 05:00:54 am
content: Well I removed the sound chip and the resistance went up to 55 ohms and the rail that was at 3.3V is now at 5V. The board still does not boot though. Got any ideas?

author: cpt.charlie
author_rank: Contributor
timestamp: April 08, 2015, 08:41:29 pm
content: Can you check the resistance from 3.3v rail to 5v? maybe there is a short

author: poot36
author_rank: Frequent Contributor
timestamp: April 09, 2015, 01:28:40 am
content: I have checked that and there is no short. I have figured out that the regulator does not directly connect to the sound chip. The rail that was shorted out was a 5V rail that was getting dragged down by the bad sound chip and reading around 3.3V.