test memory voltage with a multimeter

[xerkon]

 

This post owes completely to EMC2. All I did was take his/her discoveries and post them here.

 

I'm sort of a noob here so if this is already common knowledge feel free to erase this thread. However, today I spent about an hour searching the web for a way to test my memory voltage independant of the BIOS reading. I didn't find anything OBVIOUS at DFI street so I searched other forums. Everywhere I went things seemed pretty cryptic. Also, I found a number of people questioning how they could test their memory voltage. I finally stumbled upon the answer and have decided to post it here. Hopefully it will be somewhat useful.

 

First, when I went into Genie Bios and looked at my memory voltage and saw it go from 2.65 to 2.69 with no obvious pattern, I wondered if this was correct since my voltage was set at 2.60. I grabbed my multimeter and tested and sure enough it told me that my voltage was a STEADY 2.63, It didn't matter what my bios registered, it was steady at 2.63.

 

If you want to find test compare measure vdimm dimm voltage mem memory with a digital meter multimeter volt voltmeter (i'm trying to think of all the keywords i can to make this an easy post to find) then you've come to (what I feel is) the right place.

 

Determining your vmem mem volts is easy, at least on the sli-dr. Please check out the link below for pics.

 

Here's a link to the original post where I found this info. IN POST #10 ON THIS PAGE YOU'LL FIND A PICTURE WHICH MIGHT HELP! It's the top right pic in post #10.

 

[url=http://xtremesystems.org/forums/showthread.php?p=777631#post777631%5burl%5d%5dhttp://xtremesystems.org/forums/showthread.php?p=777631#post777631]xtremesystems.org/forums/showthread.php?p=777631#post777631http://]http://xtremesystems.org/forums/showthread.php?p=777631#post777631

 

All you have to do is secure the ground wire of your mulitmeter (I'm assuming that if you have a multimeter you know how to use it) to an isolated screw or some black power wire (i'd advise a screw because it's safer) and then touch the red probe to the + side (on my board it's the dark half of the circle, but even if you touch it to the wrong one, as long as your black probe is truly grounded, there won't be any problems) of the circle.

 

I tested this out by upping my memory voltage in the bios and verifying that the multimeter was changing with it, and it was. I read somewhere that you can do this same thing by grounding and sticking your probe in pin 7 of the dimm slot. You're NOT going to want to jam it down into where the memory would seat. But if you stick it into the hole on the left or right side you'll get the same result. I didn't like that. I thought it was a lot easier and cleaner to use the "circle" than poke around in the dimm slot, and it's safer too, in my opinion.

 

However, some of you might not have the circle with the two dots in it. I've looked over pictures of the expert board and I didn't see the circle we're talking about. Maybe you would want to try the probe in pin 7 of the memory.

 

You have to be careful and know what you're doing before you try any of this.

 

1. you have to make sure your black probe is grounded.

 

2. more importantly, you have to make sure that when you touch something with your red probe you don't accidentally touch anything else at the same time.

[Guest caffeinejunkie]

Nice post

 

will probabaly prove helpful for alot of people

 

but why not just grab a large image of a dfi board off the net and mark the things then post it

 

You did a good job with explaining it but I know alot of people are visual learners and what your saying will just confuse them lol :nod:

[GF Duke]

Anyone know of an DFI "Expert" Layout of voltage readings like this. Cause they're not the same

[xerkon]

I added a note to my post telling people to click on the link at the bottom if they needed a picture. Thanks caffeinejunkie. Your right, pictures do make things easier.

 

I took a look at a high-res pic of the expert but couldn't see anything like what's on the regular sli-dr.

[xerkon]

Anyone know of an DFI "Expert" Layout of voltage readings like this. Cause they're not the same

 

You might try pin seven in your memory slot. I'm not sure if this is universal but it worked for me.

 

I put a safety pin down in the hole of a vacant slot with the power off. Once the power started I grounded my meter and touched the positive probe to the pin. That way I could be sure I wasn't bridging any connections.

 

The pins are numbered. I think there is a "1" at one end which tells you where to go from there. Just move "7" in from the "1" end.

 

Don't hold me to this, I'm an amateur, but there are, in my opinion, three basic rules. ASSUMING you know how to use a multimeter, if your ground is truly grounded, you can poke around all you want inside your case. READ SECOND RULE!

 

Second Rule, which follows from the first. If you accidentally poke around and somehow the tip of your + probe comes in contact with two different items (traces, points, resistors...) at the same time, you're running the risk of frying your computer.

 

I did just that when I grounded my meter and tried to touch one of the pins of one of my fan headers, (fan 4, i think). There was an immediate spark and a smell of burning pcb. It really stank. My computer stayed on, but both of the fan headers on the bottom of the mobo were fried. I tried both of them, but neither worked after that.

 

I learned a valuable lesson about poking around inside computers that day.

 

But for crying in the sink, be CAREFUL!!!

 

(This is unrelated to this thread, but a good warning anyway.) do not go poking around inside your power supply unless you're sure it's drained of power. There are capacitors in there which will retain voltage for a long time and which will shock you into knowing it if you're not careful of what you're doing!