DELL Precision 650 turns on, but shows no signal in monitor?

What color is the power button and is it steady or blinking? And the hard drive light? See page 34 in manual.

What color are 4 diagnostic LEDs on front panel? If not all green, look up error codes starting on page 35 of manual.

Thank you very much! It was really helpful :)

Is it fixed?

The error code was the memory module problem, it said to reset all the modules. I did so, it worked, but now it's not working again. I tried to work with 2 Mem. modules,  sometimes it works, sometimes it doesn't. Can all the memory modules malfunction at the same time? The code is: AB- yellow, CD-green.

Unlikely all 4 would fail at once, unless there was a serious power surge or something like that.

Try following the rest of the instructions in the manual for YYGG. Remove all modules except the one in slot 4...

If you can ID a bad module, you'll have to replace it as a matched pair.

Also possible you have a bad slot on the motherboard, but let's see what happens when you test each module in slot 4.

I am having the exact same problem.  I followed the recommendations given thus far and those from the manual as suggested.  I cleared the Bios logs, which did nothing.  I put good memory in slots 3 and 4 from a different working 650 and it still gives me the same error. 

So, in my mind,  I have eliminated the memory as the problem.  Now the system will not even come up.  On the older dell's there used to be a jumper on the motherboard to clear the Bios.  Would this help?  If yes.  I have yet to find in on the 650. 

I can't run any diagnostics because the system will not come up.

Any other suggestions are appreciated.

Thanks!

I am having the exact same problem.  I followed the recommendations given thus far and those from the manual as suggested.  I cleared the Bios logs, which did nothing.  I put good memory in slots 3 and 4 from a different working 650 and it still gives me the same error.  So, in my mind,  I have eliminated the memory as the problem.  Now the system will not even come up.  On the older dell's there used to be a jumper on the motherboard to clear the Bios.  Would this help?  If yes.  I have yet to find in on the 650.  I can't run any diagnostics because the system will not come up. Any other suggestions are appreciated. Thanks!

What color is power button and is it  steady or blinking? What diagnostic LED code do you get?

When was last time you replaced motherboard battery? If you power off, unplug and press/hold power button for 15 sec and then press//hold it again for ~30 sec after you remove the motherboard battery, you'll clear BIOS and reset everything to factory defaults.

Is the RAM correctly seated in the slots? Reseat all PCI cards in their slots and remove and carefully reconnect all cables.

You might want to swap in the video card from the other 650.

Be sure to reinstall a known good battery, right-side-up, when you're done reseating everything.

Thanks for the reply and sorry for the delayed response.  I did not get an email when you responded and my frustration got the best of me.

I would like to answer your question in 2 parts.  Originally and currently: 

Originally, this problem started when the BIOS battery was going bad.  Until I obtained a new battery I continued to use the machine.  Then this problem developed.  The problem was initially intermittent and rebooting the machine usually worked.  Later, I would only iget video intermittently.  Frequently, Iit would start to boot and then go black.

At that time the power button was yellow (I believe solid yellow), A and B were yellow, C and D were green.  I had replaced the battery and reseated everything at that time.  I then put memory from a working machine into the machine in question that was not working.  Outcome was the same.

Currently, I spoke to someone who indicated that I should move the jumper from the password posts to the real-time clock reset jumper (RTCRST) and turn on the power and then move it back.  I did this and the machine did not start with the jumper on the RTCRST.  I reseated everything including the processor and the video card.  I saw your post and did everything you indicated except trying the other video card because I am not in the location with the other machines.  I also removed the other cards so only the video card is present.

Currently, the light on the power button is green(solid), A and B are yellow, C and D are green.  I saw the boot screen briefly when I put the memory in slot 1 and 4 rather than 3 and 4.  I will try the video card swap out next.  Any other suggestions or thoughts?

Thanks!

I did all this and put memory in from a known working p650.  That did not work.  I plan to swap out the video card tonight as ypu indicated in a prior post

The manual says for YYGG, to put one module in slot 4 and boot (see below). Have you tried that?

1. Reseat the memory modules to ensure that your computer is successfully communicating

with the memory.

2. Restart the computer.

3. If the problem still exists, remove all the memory modules and install one memory

module in memory module connector 4.

4. Restart the computer.

The following message appears: Alert! Operating in Debug Mode. Please Populate

Memory in Pairs for Normal Operation.

5. Press to boot to the operating system.

6. Run the Dell Diagnostics.

7. If the memory module passes, shut down the computer, remove the memory module,

and repeat the process with the remaining memory modules until a memory error occurs

during start-up or diagnostic testing.

If the first memory module tested is defective, repeat the process with the remaining

modules to ensure the remaining modules are not defective.

8. When the defective memory module is identified, contact Dell for a replacement

I tested the video card in another 650 and it works.  So it is not the video card.  Since i used memory from another working machine i do not think it is the memory either.   I tested the battery and it has a full charge.  So am  correct in concluding it has to be the mother board or the slots in which the memory is placed.  I put memory in slot 4 and no boot.  Next, i put in only in slot 2 and it still will not boot.  I do not know what to try next.  Any suggestions?

If you try booting with no RAM installed (video card installed),  no beeps probably means failed motherboard

If you try booting with no video card (RAM installed), no beeps probably means failed motherboard

Did you try all RAM modules in slot 4, or just the one?

Try this: Put a module in slot 4 and then remove motherboard battery and press/hold power button for ~30 sec. Then reinstall battery. That will make BIOS rescan the hardware and see there's only one module installed. If it still won't boot with any module in slot 4, it could be either motherboard or CPU.

And one last thing: Strip it down to bare essentials: Disconnect all drives except HDD, remove all cards except video, leave RAM module only in slot 4. If still no go, motherboard or CPU...

Thanks i will give it a try this weekend.   I wanted to add that when i replaced the video card in the prior attempt I did get beeping sounds.  Does that help in any way?  I will try your suggestions tomorrow and post the results.

when i replaced the video card in the prior attempt I did get beeping sounds.

Not sure what you meant. Did you get beeps with no video card installed or after new video card was installed?

When the new video card was installed.  I have not tried your last suggestions yet.  I think something is getting to the monitor.  Once it said your prior boot failed then went blank.  A and B went yellow.   This is all from prior steps.  I will try your last suggestions tomorrow