Blank screen after changing some parameters in BIOS

[BOUBOU1]

Hi,

after changing some things in BIOS, I was searching a way to boot on CD..PC Boot, Hard disk seems to be running(Led on and blicking) but nothing appears on screen. So not able to change anything again in BIOS.

I've try to reset the  bios with jumper but nothing better..Have you an idea ?

Many thanks in advance.

Christophe

[Grzwacz]

Greetings,

Welcome to the forum.

I am not an HP employee.

Changing MB jumper settings should have reset CMOS.

Pull the MB battery. Let the PC sit for about 10 minutes.

Reinstall the battery.

Regards

[BOUBOU1]

Hi Grzwacz,

Many thanks for your answer.

Unfortunaly, Try it but no way.. I've used this jumper to clear CMOS but not sure that it's the right one...?

Tr

Cheers.

[Grzwacz]

Hi BOUBOU1,

You're very welcome.

The image is not yet viewable. HP Moderators have to approve the image.

Please provide the product number of your PC.

HP usually provides directions on which MB pins to move to reset CMOS.

Try removing the CR2032 MB battery method.

Regards

[BOUBOU1]

Hi,

Here all the information you need: 

HP Proliant p6 series

Product N° : C5V01EA##ABF

Model N° : p6-2371ef

I've try to remove baterry for a while but not way

I've discover that the Mouse and keyboard leds are on during first seconds of boot then it shut off, seems that usb ports are disactived...

[Grzwacz]

Hi,

Your PC's motherboard specs can be reviewed at this site.

Here is the correct jumper procedure to reset CMOS:

You could also try the following procedure found at this HP site. Your PC may not have this option because it was manufactured in 2011 or early 2012.

When did you purchase your PC? The Intel H61 chipset was released for sale in Q1, 2011. Your PC is about six or seven years old. Replace the existing MB battery with a new CR2032 MB battery.

You may have to replace the motherboard using a refurbished HP Joshua MB or purchase a new PC if none of the above procedures fix this problem.

Regards

[mdklassen]

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@BOUBOU1 wrote:

I've discover ed that the Mouse and keyboard leds are on during first seconds of boot then it shut off, seems that usb ports are disactived.

---

It is not good that power to the USB devices is removed. That might be a motherboard problem, not a BIOS problem.

Anyway, from: http://www.hacom.net/sites/default/files/doc/I61GITX-F.pdf

Following [sic] these steps to clear CMOS:

1. Turn off the system and unplug the AC power

2. Remove ATX power cable from ATX power connector

3. Locate JBAT and short pins 2-3 for a few seconds

4. Return JBAT to its normal setting by shorting pins 1-2

5. Connect ATX power cable back to ATX power connector

Between the 4 SATA ports and the socket for the processor is a 2-by-2 grid of jumper-blocks:

1 top-left has 5 pairs
2 top-right has 5 pairs
3 bottom-left has 7 pins
4 bottom-right is the 3-pin JBAT block.

Clearing the RTC ("Real Time Clock") does not reset the CMOS.

[mdklassen]

>  I've used this jumper to clear CMOS but not sure that it's the right one...?

No, it is labelled "BIOS RECOVERY" -- useful only when you want to update the BIOS software, or to prevent an update.

[Grzwacz]

Hi BOUBOU1,

The image (reset CMOS) in my previous response is captured from the HP Support site for your motherboard (MB).

It clearly states this procedure will reset CMOS. Resetting CMOS should give you access to: the BIOS, all components such as USB, and the operating system. 

You may not be looking at the correct area on the motherboard to reset CMOS. Examine the MB for the correct CMOS reset jumper pins. The HP directions to accomplish this task don't specify the MB location.

Best wishes, hope you get this sorted out.

Regards

[mdklassen]

 wrote:

The image (reset CMOS) in my previous response is captured from the HP Support site for your motherboard.

It clearly states this procedure will reset CMOS.  

---

Sigh.

From: HP and Compaq Desktop PCs - Motherboard Specifications, H-Joshua-H61-uATX (Joshua)

you are only partially correct. The text reads:

Clearing the CMOS settings

This motherboard has a jumper to clear the Real Time Clock (RTC) RAM in CMOS.

-----------------

This is an example of bad document writing, because it does not explain that the CMOS stores both:

• BIOS settings that you view/change during BIOS SETUP,
• the RTC -- the "clock" on the motherboard,

while the technical writer(s) only documented how to change the RTC.

The RTC allows the computer's clock to stay accurate, even when the computer is disconnected from all power sources (wall outlet or laptop battery).  Example: if you decide to upgrade RAM or the disk-drive, you unplug the computer, make the hardware change, and then plug-in the computer -- there is no need to reset the motherboard's clock.

The technical writer(s) did not document the JBAT block, nor what to do with it.  That is their mistake.

From: https://www.lifewire.com/what-is-cmos-2625826

CMOS (complementary metal-oxide-semiconductor) is the term usually used to describe the small amount of memory on a computer motherboard that stores the BIOS settings.

Some of these BIOS settings include the system time and date as well as hardware settings.

Most talk of CMOS involves clearing CMOS, which means to reset the BIOS settings to their default levels.

_____________

I will repeat: it is ONLY by manipulating that JBAT 3-pin block that clearing CMOS can be performed.

Of course, if you only want to reset the RTC, without clearing CMOS, follow the existng HP documentation.

Moral of the story: don't believe everything you read on the Internet, but please understand what you do read, to avoid creating confusion on this forum.