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Strange Issue, Maybe PSU-related?

Last response: in Components
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July 27, 2010 1:34:34 AM

I have a strange issue that has stumped EVGA, Intel, and the Geek Squad. Let's see how this works out...

I'm upgrading my system (it's a year old bought from a small computer store) and received my shiny new video card in the mail today. It's a GeForce 9800 GT. I plugged the bad boy in, started my computer, and was delighted to see the card working with a display on my monitor. So I go to type in my password and load the drivers.

Here's where the problems start - my keyboard isn't working. This is strange since it worked in the morning. I use a PS2 keyboard, so I went across the street and borrowed a USB keyboard. Same issue, it didn't work. I took out the video card and both keyboards still weren't working.

After having a good rant across the street, I came back, tried again, and the keyboard was working again. To be cautious I called EVGA (video card provider) and then Intel (motherboard) to figure out what happened. After no clear answer I tried the video card again. Just like that, the keyboard stopped working again. I immediately removed the video card, but it hasn't come back.

I tried talking with Intel and then took a friend's suggestion and talked to Geek Squad. Both were stumped.

My brother suggested a possible power supply issue. My PSU is rated at 450W, and since the video card requires 300W it shouldn't be an issue. I've used the power supply calculators online and they suggest a PSU of 383W, which I clearly have. They only think I've seen which MIGHT be of some relevance is the article posted on this site that recommends a 400W PSU with 30A at 12V (my PSU delivers 22A @ 12V).

I realize that replacing the PSU is a possibility, but are there any other suggestions of what might be happening to my computer?

Best solution

a c 288 ) Power supply
a c 202 U Graphics card
July 27, 2010 1:38:27 AM

22A on 12V(264W) isnt a 450W power supply, its a decent 300W power supply. What are your full system specs? Can you post your power supply make and model?

If you want a quick way to rule out the PSU you can grab a Corsair 400CX from newegg for $30 after $20 MIR, while its rated 50W lower than your current PSU it provides 8A more on the 12V rail than your current PSU.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
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a b ) Power supply
July 27, 2010 2:42:52 AM

+1 corsair 400cx.
also check the motherboard for bad capacitors (the little cylindrical things that stick out), look for capacitors with brown goop leaking out or bulging tops.
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July 27, 2010 12:42:30 PM

hunter315 said:
22A on 12V(264W) isnt a 450W power supply, its a decent 300W power supply. What are your full system specs? Can you post your power supply make and model?

If you want a quick way to rule out the PSU you can grab a Corsair 400CX from newegg for $30 after $20 MIR, while its rated 50W lower than your current PSU it provides 8A more on the 12V rail than your current PSU.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...


Specs:
OS: XP SP3, 32 bit
Cpu: Intel Pentium D 820 @ 2.8 GHz
Mobo: Intel Model D945GTP
Memory: 1GB (2 sticks of 512 MB DDR2)
Graphics: Intel 82945G Express Family Chip Set
Hard Drive: 250 GB, that "sea-something" brand
PSU: EDIT: 450 W (Viotek)

I bought this computer at a small computer shop for $350. When I started looking into the specs to upgrade I realized that the quality wasn't too high. The motherboard hasn't had technical support since 2007, fo instance.

I looked into the PSU found it: http://3btech.net/newv2vi4520p.html

There are some terrible revies of this brand floating around the internet as well. I'm thinking that if I need to replace this, maybe I should get a PSU rated at 550W instead to support the additional RAM and new GPU I bought. Still, it doesn't solve the immediate issue. I talked to the tech people at work and they suggest the I/O is having issues, but all their solutions require using a keyboard, so I'm stuck in limbo until then.
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July 27, 2010 1:50:32 PM

Well, at least while I'm at it I cn upgrade the PSU too. I went ahead and got the 400cx from newegg. I highly anticipate removing the other one and put it to good doorstopping use :) 

Thankfully this isn't very expensive, and if the keyboard doesn't start working by then hopefully this will help. If not, then I know there is a motherboard issue and will have to replace that too (although, in the long run, I probably should).

I think I'm going to make this computer passable, build myself a mid-level gaming computer for home use (over the next 4 or 5 months), and use the old one as my school computer. That is, if I can get it to log in anytime!
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a b ) Power supply
a b U Graphics card
July 27, 2010 1:59:58 PM

Let us know how it goes. Good luck.
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July 29, 2010 12:28:25 AM

Best answer selected by sf_torquatus.
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July 29, 2010 12:43:34 AM

Everything seems ok. Here's how it went:

Several hours after buying the PSU I went home, tested the computer, and officially gave up hope. I ordered a new motherboard online in a combo with an intel pentium dual core (which is about 80W more efficient than my crappy Pentium D according to PSU calculators). I figured I should practice taking apart a computer since I've never done anything like this, so I got out the screwdrivers, unplugged everything, and let them sit (the more sensitive components sat in small boxes).

I spent a great deal of time today learning how to swap my hard drive into the new motherboard. It took so long since my computer was storebuilt and I didn't have an xp cd, product key, or any installation information on my copy of Office that came with the computer. Needless to say, learning about that took a while......

My plan for the evening was to put the computer back together so I'm not doing it for the first time with a new motherboard. The plan was to test it, then when the hardware arrives tomorrow test the new PSU and see if I can't boot everything up and save some backups on my external. I plugged it in and the computer got to the BIOS just fine (and my keyboard worked!). Turns out the only thing I messed up with my first "installation" were the front panel LED displays :) 

Long story short - it wasn't the motherboard, it was the PSU. The video card put so much strain on the system it must have faulted the keyboard I/O, but apparently letting it sit unpowered for a long period of time lead to its recovery.

Since this is an old motherboard (out of technical support from Intel since 2007) I'm going to go ahead and switch the motherboards anyway (ECS G31T-M7 board). Sure, I'll have 2 less RAM slots and the CPU ports are the same, but since the PSU was obviously a cut cost I'm having my doubts about the integrity of D945GTP boards...
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a b ) Power supply
a b U Graphics card
July 29, 2010 1:40:05 AM

Thanks for the update :) 
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a b ) Power supply
July 30, 2010 2:50:35 AM

ECS G31T-M7
exact same board i have! its a great little thing for the price, but be aware that while you can change the cpu frequency (in bios), you cant the cpu voltage, so do expect more than like 200mhz oc :) 
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July 30, 2010 6:42:45 PM

It seems as though the troubles keep coming...

I got the new corsair power supply and hooked it up. It worked fine, so I plugged in the video card only to have deja vu strike again. The keyboard wasn't working.

I don't understand how this can still be happening. The card loads up, displays on screen, and its built-in fan work just fine. It's almost as if the computer has forgotten the keyboard driver. I unplugged the card and took it out of the motherboard. I turned off all the power and will wait it out until the keyboard works again. From this last week I learned it can take as little as 30 minutes and as much as 2 days, from unplugging the supply from the wall to disassembling the entire computer and letting it sit in boxes for 24 hours.

I got off the phone with evga and they say the card (9800 gt) may not be getting enough power. I don't see how that's possible since the new power supply has 30A on the 12V rail (360W) and the system as a whole only consumed 215W according to power calculators. I tried their suggestion of booting u pthe computer with the bare minimal attachments (power, 1 stick of RAM, and CPU) to no avail. I'm running out of ideas and only more questions are coming to mind:

Is the video card defective? It it is, then why is it showing a display and physically working in my motherboard?

Do I need an even bigger power supply? Even with the new components and the video card power estimation sites give me a minimal rating of 300W and maximum of ~350W...

Do I need to install the video card drivers before puting the card in my motherboard? This is going to be my next course of action regardless. Before my motherboard drivers were installed my mouse didn't work. Luckily my keyboard did and I could initialize the driver setup using keyboard hotkeys...

Should I buy another video card and see if I'm having the same issues? (This is getting very costly very fast...)

Please help!
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a b ) Power supply
a b U Graphics card
July 30, 2010 6:55:01 PM

Have you tried it in safe mode?

That PSU should be enough for your system. I don't think that's the issue.
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July 30, 2010 7:03:57 PM

Can I access safe mode without a functional keyboard?
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a b ) Power supply
a b U Graphics card
July 30, 2010 7:51:48 PM

If it works in the BIOS, you should be able to. You've got a strange situation, so it'll be interesting to see.
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July 30, 2010 7:53:25 PM

I see. I'll try to access BIOS using the motherboard jumpers. I'm glad I could be a learning experience for strange problems :) 
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a b ) Power supply
a b U Graphics card
July 30, 2010 8:08:33 PM

The BIOS is a little different. It'd be good to know if you can get in there too. But I'm curious if your mouse and keyboard will work in safe mode.

Tapping F8 on startup should get you to the safe mode options. Often, tapping the delete key on startup will get you into the BIOS. The keys can vary from PC to PC though.
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July 30, 2010 8:48:25 PM

(Typing on my exceptionally crappy laptop) - The system has been sitting without power for about 2 hours. I plugged everything back in and tried to start up to no avail. I then unplugged everything in the motherboard and it's going to sit like this for a few hours more. If it doesn't work I'll have it sit a full 24 before starting to get worried.

I tried using the CMOS jumpers and my computer doesn't even power up when I change them. It even takes a few tries to get the power to go on when I put them in the right position.

Suffice it to say, I couldn't get into BIOS or safe mode (I was tapping F8 and Del continuously). Looks like I have to wait it out. I was also thinking about plugging in the old power supply and seeing if it works. Maybe the fault is in the PSU and not the motherboard...
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July 30, 2010 9:20:22 PM

take out the entire pcfrom the casing and run it. make sure u place the mobo on top of something insolative lkke ur mobo box. power it up with a screw driver after connecting the new psu, cpu and hdd only. and ram offcourse. it ur keyboad is fine, then add ur gfx and turn it back on to test.

something tells me ur casing may be shorted or something

keep ur fingers crossed
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July 30, 2010 10:34:42 PM

Shorted casing? Now there's an idea...

My casing doesn't have screws, it has metal notches that hook on to the motherboard. I need to pull the board on them far enough to uncover the screw hole in the side. I suppose there would be a problem the metal was shorting the motherboard!

This is what I'm going to do - I'm typing on my desktop right now. After sitting for half an hour with an unplugged motherboard I connected the old power supply and it started up fine. First, I'm going to connect the other power supply to make sure that unplugging everything on the motherboard is a valid way to fix the issue of the keyboard not working. If it doesn't work, then I know the power supply is shorting. Then, I'm going to try your idea with taking the components out and setting the motherboard on the box (with the insulating styrofoam beneath that. Let's see how this turns out...
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July 30, 2010 11:44:45 PM

Well that was bizarre.....

I put the motherboard on its box, hooked up the hard drive, the psu, and the on-switch cable. I had to put the tower on my chair sitting up so I didn't have to take anything else apart!

Pre-Test - I put in the 400W power supply and the computer started up with keyboard functional. I thought that was interesting.

Test 1 - Motherboard on the box with the essential components plus my mouse, keyboard, and monitor. I started things up and the keyboard didn't work. This is strange since it was working fine in the box.

Test 2 - I changed to the other power supply. The keyboard still didn't work. This is strange since it too was also working fine a few minutes before.

Test 3 - I put in the new power supply and tested the second 4-pin 12V hookup. This didn't work, so the problem isn't the connection.

Post Test - I put the computer back together, booted up, and now my keyboard is working fine.

I'm really not sure of what to make of all this. I'm going to test my mettle with the video card one more time. If it doesn't work I'll have it narrowed down:

1). The power supply isn't big enough. Power rating web sites tell me that with the card I'm drawing 350W. Since the 12V has 30A (360W) this is cutting it close.

2). The case isn't grounded causing a short that takes out the keyboard. The pins that hold this board and the old board are the same, so there is the potential for consistent error.

3). The video card is bad. I bought it from ebay, so it just might be bad. I find the same card on newegg with a $30 rebate and the upc of the box was cut off "for extra savings" according to the auction page. I have a suspicion that it was bought, they got the rebate, and sold it back to try and make a profit (I won for $48 + $11.99 tax, so that effort failed). I side a little bit with the evga technical support people that this is a power issue, but if everything else fails the card will be the last thing to replace.

My plan right now is simple (at least in my mind). I'm going to buy a bigger power supply (the corsair 650W). I ran my budget and saw that I have just enough. Since I plan on building a mid-level gaming computer over the course of the next 6 months, I'm going to need a bigger power supply anyway. I will have two computers, so my current desk top will become my graduate office computer. If I took out the video card and used the 400W corsair power supply I will be in great shape. If the 650W works (which I will be extremely upset if it doesn't), then I can store the 400W for when I make the computer switch. If the 650W doesn't work I'll get the new case to try and solve a potential grounding issue. If that doesn't work I'll buy a new video card from a local store and return it within the day if it doesn't work. If nothing works until that point I'll just accept it as God's way of telling me I shouldn't play Starcraft 2 for a long long time!
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July 31, 2010 1:48:51 AM

New development - I don't know what I was thinking when I tried the video card again. It didn't work the first three times, so I don't know why I thought it would work the fourth. Bam, keyboard is out again. I tried swapping the power supplies, but the second one did no good.

About half an hour later I tried again. After it didn't work I removed the motherboard and sat it on top of its box. When I touched the power supply to ground myself I felt a lot of static on its surface. After I grounded the board and put it back in it worked. Things are looking a lot like bad grounding on the case. I found a cheap one with good reviews (the last thing on newegg I can afford to buy for another month!), so it will come with the better power supply. With that, I've officially replaced everything inside the computer except the hard drive and dvd drive. The funny thing is, it will vastly outperform the older version for about the price I bought it. I'll let you all know if it works in a few days!
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July 31, 2010 5:55:18 AM

like u said, its nott the power suppy. so i don see y u need to get new one at this time. buy psu gfx later.

cheap casings r thee reasons y thetly get shorted in the 1plc. be careful wat u get :) 

also make sure the psu is connected to the wall via a 3pin plug. this is very imp in ant electrical device. make sure wall earthing wiring is working
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August 3, 2010 10:42:17 PM

Update

Nothing is working. Absolutely nothing.

I checked the outlet. It is grounded correctly.

The new case arrived and I switched everything over. When I put the board on the mounting screws it fit over some just fine, while others were off JUST enough that I couldn't screw them in.

I started everything up and the ever-persistent keyboard just won't work.

The computer has been working fine all weekend. The keyboard stopped working when I changed the power supply.

I took out all the essentials and tried booting it without the case. Nothing.

I'm completely out of ideas. At first I thought it was the video card, then the power supply, but the issue seems to be with the motherboard itself. How can this be? It's new, it should work! It's been working fine the last few days. Why does such a simple change cause it to malfunction?

Should I RMA the motherboard or keep trying to find this ever-elusive short? RMA would be difficult seeing as I'm moving 900 miles in 5 days then 900 more miles 6 days after that. I don't want to take it to a technician, but at the rate I'm going I will have lost my mind entirely...
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a b ) Power supply
August 4, 2010 3:07:22 AM

maybe its the keyboard?
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a b ) Power supply
a b U Graphics card
August 4, 2010 3:27:41 AM

I didn't see a response to if the same problem occurs in safe mode?
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August 4, 2010 1:05:36 PM

No, it's not the keyboard. I've tried USB keyboards and they don't work either.

I can't get into safe mode because I can't press F8. I can't press Del either to get into BIOS. When I clear CMOS it does not autmoatically take me into the BIOS screen.
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