Optiplex 780 memory problems

[ladyrebelle]

I have done everything I can think of. So here's what I've done:
I originally had an Optiplex 745 (minitower) and I upgraded the motherboard to the Optiplex 780 (minitower) one (my husband cut out part of the back of the tower so the motherboard would fit in it).

My hardware:
Optiplex 745 MT case with an Optiplex 780 MB
Q6600 core2quad processor at 1066mhz
500w PSU
BFG Nvidia GeForce 9800gt 1gb

Well, here's the problem:
I've read that I can use up to 16gb of ram, and so I bought 16gb of ram (4x4gb). I read that I can also use either 1066mhz or 1333mhz, so I got the 1333mhz. The brand is TeamElite and I've found a lot if good reviews on it. My husband and I have tried testing out each stick one by one, and it won't power up with any if them. No beeping at all. But the number 4 was lit up. Upgraded the bios to the latest version. I do have 2 older sticks of ddr3 ram, one is a 2gb and one is a 4gb (they're both 12800mhz), but they both came out of my dad's Gateway, so they're pairs. Well, the 2gb will work, but the 4gb won't. Seems like anything over 2gb won't work and I just don't understand that, when the Dell guides state that it can use 4gb modules and a lot of other people were able to get 4gb modules to work.

And another weird thing that's happened, is that I can't turn off my computer by the power button. I can turn it on by the power button, but not off. If I want to turn it off, I have to shut it down whenever I'm in Windows, or unplug it or flip the switch in the power supply off.

Anyone able to help me? 🙁

 

[Kisianik]

Let see.

First about on/off situation. You started to have this issue when you moved motherboard from 780 to 745? Why you did the move, why not just use the whole 780 as is?

Are front panel connectors for 780 and 745 are the same configuration? If you still have 780 case, can you look at wires locations?

Now about RAM. Dell systems are very picky regarding RAM. RAM must be low density, specific voltage, not just the proper speed.
The best way to get RAM for older models is to follow Crucial Memory Adviser, so far no one complained that memory obtained this way did not work. Don't pay attention to higher speed posted by Crucial, your BIOS will slow down memory to factory specs, according to Crucial, this way Crucial cut costs and adapting principle "one fits all".
Purchasing from Crucial is easy, up to 45 days return policy if RAM doesn't work, and a free shipping, and Life Time warranty with excellent support.

Many special or advanced RAM modules would not work on older Dells, not much can be done here, you just learned this the hard way.

 

[ladyrebelle]

Ah I see. Yeah the ram I got I don't think was the low density one. And the motherboard, I bought it by itself off of eBay because I'm tight on money, so there's no case.

 

[Kisianik]

I see, then it would be a long battle with power switch, this is the most difficult thing to figure out, I will need some time to do so.

Can you upload and post images? As I will need picture of you power connector (which coming from the front panel) from the side (view from top, so i can see where individual wires attached to) and from the bottom, I hope i can find large picture of 780 motherboard.
I will look for connector picture as well, but it is rare in large file, usually it is pictured very small.

Is your husband, or you are good with tools, especially electric tester and wires? There is a possibility that motherboard connector would have to be rewired, it seems that power and reset wires got mixed up.

I will comeback to this thread tomorrow, got to work sometimes.

 

[Kisianik]

Front I&O Panel connector - mission impossible, completely proprietary and in ribbon form.

This is Optiplex 780 Mini Tower motherboard

That connector attaches to small black one on motherboard next to BLUE PCIE lock handle, is it correct?

And this is the picture of it, is this correct?

It should be part number P9874 or 0P9874. Can you check your cable if it is the same part number, it should be listed on the cable?

If it is different, please post here.

 

[villandra]

On the RAM, first, an older Core 2 Duo isn't likely to be much faster or do more with 16 Gigs of memory. They will upgrade to 8 Gigs, so I'd stick with that.

The things appear to be finicky about what memory you can install and how you install it. I work for a computer refurbishing/ reselling company and we have trouble installing RAM and getting it to work with these.

The cheaper RAM doesn't seem to work with them. I'd suggest trying Hynex, Skynex, Samsung or Kingston? NOt sure I have that last name right. NOT Crucial, which often gets suggested.

If there are more than two slots, make sure you have RAM in DIMM 1 and DIMM 2 - those are going to be numbered on the board or else the manual will tell you how to identify them, and they'll be the same color.

You may need to install one stick, reboot, and install the other stick. Starting wtih DIMM 1.

As to turning the computer off with the power button, you don't turn a computer off with a power button, you shut it down via the operating system, or you're going to corrupt files and eventually the operating system won't boot. It's a rather ?????? !!!!! matter.

The power button should still work. But if you're able to turn it on with the power button you probably did the wiring correctly. The thing is, though, that to turn a computer off with the power button you have to hold the button in for a while; it's an emergency procedure for when nothing else works.