monitor stuck in power save mode

Hi madyliz64,

Welcome to Dell community!

May I know the status of the Power Button light? Also, there are four Diagnostic lights at the front of the Dimension C521 chassis. May I know if they are glowing and if yes, in what pattern? Please try the steps in the following article to troubleshoot the issue: http://dell.to/16YSfQb

the power button is yellow but no other lights are showing. the button on the monitor is green to start with then changes to amber and the black screen. I have tried the steps in the articles have seen these on other sites.

 I am hoping to try another monitor tomorrow a dell one from my sons PC

I don't know if its working as the monitor is black i can hear the fan as though it is working.

Is the C521 working? A monitor in "power save" mode is a symptom of no video signal from the PC.

Hi madyliz64,

If the power button light is solid yellow, a pre-POST (Power-on self-test) failure has occurred. The diagnostic lights are available at the front of the tower below the USB, Microphone and headphone connectors. Please confirm if any of the diagnostic lights are glowing.

There are no other lights showing, and I have now tried connecting to another Dell monitor which I know is working and it has the same reaction monitor in power saving mode. So think it is definitely the tower that has a problem. Hope you can help thanks

Hi madyliz64,

Refer the following link for the Dimension C521 service manual: http://bit.ly/1d5tq3u

Please follow the below mentioned steps to troubleshoot the issue:

1. Disconnect the power cable from the tower, press and hold the power button for at least 15 seconds to remove the residual power
2. Follow the instructions in the manual to remove the computer cover
3. Remove the memory modules from the tower
4. Connect the power cord and switch on the computer
5. Check and let me know if any beeps are heard
6. Install the memory modules, try switching on the computer
7. If issue persists, try reseating the video card (if the computer has PCIe video card)

Do let me know the results.

Hi madyliz64,

If beeps were heard when you powered on the computer without the memory modules installed, motherboard has encountered failure and it has to be replaced. Refer the following link to check the computer’s warranty status: http://dell.to/10pMa86

If the computer has active warranty, please send me the service tag and registered owner’s name on the computer in a Private Message. To send me a Private Message, click my User name, and then click Start Conversation.

If the warranty on the computer has expired, you may contact our expired warranty services to purchase/replace the compatible parts. Please refer the following link that has contact details for our Expired Warranty Services: http://dell.to/14FoBtb

HHi have done what you suggest and no beeps. I believe I have an integrated video card. As cant see any other obvious cards. :(

I did not hear any beeps so what does that mean?

Ok thanks i am out of warranty so, I will hav to ring th uk  number tomorrow, to see what they say. I hope it is not to costly for a motherboard. Does that mean I have lost everything on my pc? 

Thanks for your help

Hi madyliz64,

My apologies, I missed the word "not". What I meant was, if beeps were not heard when you powered on the computer without the memory modules installed, motherboard has encountered failure and it has to be replaced.

Hi madyliz64,

Hi madyliz64,

You're welcome!

Data is stored on the hard drive and replacing the motherboard will not lead to data loss.

Do let me know after contacting Dell UK Expired Warranty Services.