Please help me... PSU OK, but...

[Muse]

I've been running a Gigabyte GA-K8n Pro motherboard midtower system for years. I think the PSU is close to death. I'm about to swap out that PSU with another and a different motherboard, CPU, RAM, and video card.

I posted the new components today -- the motherboard and video card and RAM are not new, but the PSU is new: EVGA 550 G2. Did this out of the case. However, I wanted to test my theory that the old system with the Gigabyte GA-K8n Pro motherboard wasn't working OK because the PSU was bad. So, I swapped out the old PSU (Corsair vx550w) with the new EVGA 550 G2.

Everything seemed OK when cabling things inside except for one thing: The connector to the motherboard isn't the same. The Gigabyte GA-K8n Pro motherboard's power connection is 10 connectors wide. The cable coming from the EVGA PSU is 12 connectors wide. I figured maybe it would work OK if I used it anyway and the cable went on, starting at the left and there were 2 rows of 2 connectors on the right side that don't connect to anything. However, the machine doesn't POST. The PSU starts up when I hit the power button but I see nothing on the screen, heard no beeps.

What's up with this? Isn't that EVGA PSU an ATX spec PSU? Will it not work with the old Gigabyte GA-K8n Pro motherboard? My replacement board is a Gigabyte EP45 UD3R (3 PCI) Motherboard.

 

[VirtualLarry]

There are various ATX PSU standards. The "old" (like, really old, 2000-era) spec, was for a 20-pin motherboard connector. Later on, they added four wires, and made it a 24-pin ATX connector. Most modern PSUs have a 20+4 connector, meaning, that the four additional wires are on a sub-connector, that can be gently bent away, so that you can still plug them into the few older motherboards still in service with a 20-pin mobo connector.

 

[Muse]

There are various ATX PSU standards. The "old" (like, really old, 2000-era) spec, was for a 20-pin motherboard connector. Later on, they added four wires, and made it a 24-pin ATX connector. Most modern PSUs have a 20+4 connector, meaning, that the four additional wires are on a sub-connector, that can be gently bent away, so that you can still plug them into the few older motherboards still in service with a 20-pin mobo connector.

Thanks. Yeah, my older PSU (the Corsair vx550w) has the fold away 4 pin segment on the power connector, but my new EVGA 550 G2 has a solid 24 pin connector. It does fit if shifted to the right, but for whatever reason I'm getting no video and no beeps when I try to boot the machine.

I have a 2nd midtower that has an old ATX 350w PSU. I could rip it out of there and see how the system works with that. A bunch of work, don't know if it's worth it because I'm rebuilding the main system anyway probably early next week (Monday, etc.). Will see how I feel about messing with this tomorrow. Trying that 3rd (old but working) PSU in the system would help in pinning down whether that Corsair PSU is OK or not.

 

[VirtualLarry]

I'm a little concerned, when you say "shifted to the right".

Holding the PSU's ATX 24-pin connector wires, with the ATX 24-pin connector facing away from you, with the clip on top - the extra 4-pins should be on the LEFT, not on the right.

Edit: Yep, I just grabbed a PSU to double-check. When you plug in the mobo connector, the 4 extra pins on the 24-pin ATX connector coming from the PSU should be on the LEFT.

 

[Muse]

This was with the clip at the bottom, so I guess my Right is your Left on this. I'm pretty positive the connector will only fit one way. I figure it should work. It may not work because of difference(s) in the supplied voltage. Don't know.

Anyway, I'm going to try what I said and remove that EVGA 550 G2 and put in the 350w PSU that's in my second midtower. I bought it's case many years ago at a computer show in Oakland, CA. It was really cheap. The case was something like $25. I looked up it's PSU and a reviewer had tested it extensively and was extremely positive about it. I drilled dozens of big holes in the PSU case to facilitate cool-running. I figure the odds are really good that the computer as-is will run with the 350w PSU if everything is OK. If it doesn't, I have to think there's a problem with something else, possibly with that motherboard. If the system works OK with the PSU from the cheap case (i.e. 350w), then I have to conclude that the Corsair vx550w PSU is indeed bad. Otherwise, I have to think the Corsair may actually be OK. I think the former is more likely.

 

[Muse]

So, I swap in my 3rd PSU, the 350w. It's an L&C LC-A350ATX. Has only 20 pins on the mobo power connector. I get the same thing: All fans are powered but no beep codes at all and nothing on the monitor. Nothing.

So, it's doing this with all 3 of the PSUs I have now. I have to think the PSUs are probably OK (the Corsair is still suspect, but it might be OK). I don't know why this is happening. Even with the Corsair in there, the system would boot most of the time a few days ago. Now nothing but fans.

Figure I'll put the 350w L&C back in my second midtower and use that for the next few days and then put different mobo, CPU, video card, RAM in the first midtower come early next week.

 

[MrTeal]

If your new system works fine, and the K8n doesn't work with any of the power supplies, I would probably lean to it not being a PSU issue at all but a MB issue. I might just have finally given up the ghost.

 

[Muse]

If your new system works fine, and the K8n doesn't work with any of the power supplies, I would probably lean to it not being a PSU issue at all but a MB issue. I might just have finally given up the ghost.

I agree with this logic and inasmuch as I have a replacement set of components and I was intending to replace that mobo etc. anyway, I'll just swap it out with the replacement stuff early next week. The mystery of just what's wrong with the system will go unsolved. Doesn't make sense to spend time messing with it. I do have my 2nd midtower, it functions AFAIK. I'm about to resinsert its PSU and fire it up, reconfigure my connections and figure I'm OK til next week.

 

[Muse]

So, I put the 350w L&C PSU back in midtower 2, hook everything up and fire it up. Incredibly, that system too hummed right up, no beep codes no video! WTF??? I mess with it for 1/2 hour, not believing what's happening. Finally, I hear a faint beep when resetting it. Still no video. I get an idea: Turn off power. Not just shut down the machine, but shut off the power strip to which it's attached. After doing that I get a beep again, no video. Then I turn off the monitor and turn it on. Viola! Windows is booting. It's Windows 2000 on that machine, believe it or not. It's booted now. I'm not turning off this machine for the next few days... it stays on. Meantime, on Monday or by Wednesday, I'll rebuild midtower 1 with replacement components. I POSTed those components a couple days ago. I'm wondering if there's something else going on here, maybe an electrical problem in the house. Hmm. Been very rainy lately. Over the weekend a storm is coming in that they say is a 10-25 year rain storm... a monster. It's going to be a weird weekend, I'm pretty sure. Meantime, I should have HDTV using midtower 2 because it has it's own TV card. Want to watch the NFL playoffs, timeshifting.

The midtower 2 system is so old, it doesn't even support SATA. Barely supports USB, there are, I think, 2 USB connectors on the back of the system. I have a single USB extension cable running to the front and a hub plugged into that. It's PSU doesn't support SATA! System specs:

MSI KT3 Ultra2 mainboard
AMD Athlon XP 1700+ CPU
BFG geforce 6600 GT OC AGP video card
DDR - Crucial/Samsung Original PC2700 2x512 MB for 1 GB
MIT MyHD 120 HDTV card with DVI daughterboard
Windows 2000 Pro

 

[Muse]

I go to my workout, come back, have dinner and attack the problem again. I get midtower 2 to boot to Windows 2000. Sometimes it boots sometimes it doesn't. Don't know whatall's up with that. Anyway, it's on now, I have things working and I think I'll just leave the machine on for a few days. Hopefully, it will keep working. The other machine won't boot, I'll tear it apart and install mostly all different things starting with the mobo in a few days.

 

[Muse]

My strategy to have a 2nd midtower set up and working has paid off. I have kept it partly because the MyHD cards only tune one station at a time and you can't double up in one machine. Since Midtower 1 is down, I have my backup Midtower 2 good to go. I also plundered it's PSU for testing purposes (it's back in Midtower 2 now), the trusty L&C 350w.

I just bought an HD Homerun tuner (still in shrinkwrap), that has 2 tuners and presumably I won't be needing the 2nd system for alternate channel recording, but I may keep it as backup anyway. I have the systems stacked, 1 on top of 2, they are bolted together and bracketed to a vertical surface.

 

[VirtualLarry]

MSI KT3 Ultra2 mainboard
AMD Athlon XP 1700+ CPU
BFG geforce 6600 GT OC AGP video card
DDR - Crucial/Samsung Original PC2700 2x512 MB for 1 GB
MIT MyHD 120 HDTV card with DVI daughterboard
Windows 2000 Pro

That's some classic kit right there.

I used to be the type to "run it till it dies". But I've had far more techno-lust lately, upgrading nearly every recent generation.