1st build, 1st boot... NO! Endless reboot cycle!

After months of planning and preparation, I finally finished putting together my first build. After checking all connections, I powered up. The front panel LED's lit up, the fans started spinning, and the DVD drive made a typical spinning noise.

Within about 6 seconds, however, everything abruptly shut down. No beeps, no post, no monitor display. Two seconds later, without touching anything, the computer powered up again. Five seconds later, off again. Two seconds later... In other words, an endless reboot cycle.

So I went through a checklist, trying to pinpoint the problem. I disconnected one hard drive. Same result. Then both drives, then the DVD drive, then the fan controller. I connected the CPU fan directly to the mobo's CPU_FAN header, thinking the board was shutting down as a safety precaution when it didn't detect a CPU fan. I switched the 2x4 pin ATX 12V power connector with a 2x2 pin connector, since my board and PSU support both. Each time I got the same exact reboot cycle.

Then I decided to completely disconnect the ATX_12V power cable to the mobo, leaving only the main 24-pin power connected. Surprisingly, the computer powered up and didn't shut down! The problem is, nothing else happened. No beeps and nothing displayed on the monitor, even after re-connecting all peripherals. All components seem to work fine. The fans (and fan controller) work, the DVD drive opens, the HDD's idle. But nothing actually happens. I can't enter BIOS since it doesn't to post, or at least, nothing shows up on the monitor. When I plug the ATX_12V power back into the mobo... reboot cycle.

So that's where I'm at now. I'm sure there's tons of info on the net about issues like this, but every homebuilt system is different. I'm hoping someone can point me in the right direction. I'm also really hoping it's not a faulty motherboard.:cry

Here's the all-important spec list:

Gigabyte GA-EP35-DS3P
Corsair HX-520W
Intel E8400 Core2 Duo w/ Ultima-90 heatsink
Asus EN7300GT
4GB GSkill DDR2
320GB WD SATA HDD
640GB WD SATA HDD
Samsung S203N DVDRW
3 fans w/ Rheobus Sunbeam 5.25" controller
CoolerMaster CAC-T05 case

 

The first thing that comes to mind is a bad PSU. The second thing is that maybe the front panel stuff isn't connected correctly; the front LEDs, the power switch, reset switch, or the power switch/reset switch is stuck or faulty. If you had mistakenly plugged an LED into the power switch header or the reset header, you'd get all sort of crazy activity. So maybe disconnect everything connected to front panel header, and try turning on the PC by briefly touching the two power switch pins with a screwdriver.... and pull out all the RAM except for a single stick, and maybe disconnect the Rheobus controller just to keep things to a minimum....

 

I'll re-check the front panel wires and try one RAM stick. Turning it on with a screwdriver scares me though . With my luck, I'll fry the motherboard.

 

Just tried one RAM module. No luck. Also checked panel connectors. I even tried reversing polarity of power switch connector. Same thing.

Could this be a bad motherboard, rather than PSU? I'm starting to read reports of rebooting issues with this board..

 

this seems quite similar to my problem
i have just replaced my PSU and when i unplug my SATA HDD it runs as normal but with it plugged into the power it just turns off as soon as i power it up

 

I just tried clearing the CMOS by removing the battery for a minute. Then I tried the RAM module in another DIMM slot.

When that didn't work, I completely removed the motherboard from the case and set it on the retail box. With only the CPU/heatsink/fan, video card, and RAM connected, I plugged the power in and shorted the power switch... and got exactly the same result. Continuous reboot.

So.. I'm guessing this all means a) bad motherboard or b) bad PSU. I'm thinking it's the board, based on similar issues I've seen people have with it.

Unless anyone has any other advice, I plan to RMA the mobo for an exchange. If that doesn't work, then I'll be 99% sure it's the PSU.

 

OK I think I'm finally getting somewhere!

I was about to take off the heatsink and reinstall the CPU, but first I decided to try my other RAM stick in the first slot. Then I cleared the CMOS by shorting the jumper with a screwdriver. When I started it up, the Gigabyte logo came up on the monitor! After booting up, it said something like "enter system disk..." etc.

At this point the board is laying outside the case on the box. Only the CPU/HSF, video card and one RAM stick are installed. Nothing else. But it works!!!

I guess now I need to reinstall everything. I'll let you know how it goes..

 

I may have it narrowed down to the memory.

When I use only one particular stick of RAM (call it RAM1), it boots right up. I can enter BIOS and everything. If I add the other stick (RAM2), it gives me the continuous reboot cycle. However, if I use only RAM2, in any slot, it gives me the same reboot problem.

I tried loading "optimized defaults" in BIOS, then installing both sticks. Reboot cycle, no post. Then I tried loading "fail-safe defaults". Same results. I tried the RAM in slots 1/3 and also 2/4.

This is the RAM I'm using (2x2GB G.Skill DDR2 800). It's supposed to be easily compatible memory. Voltage should be 1.8V-1.9V. The only relevant option I see in BIOS is DDR2 Over-voltage Control, which only allows you to overvolt (obviously). I just left it set to "normal".

Any ideas? Bad module possibly?

 

It could be a bad module, but since it worked out of the case, it makes me wonder if you have it installed in the case correctly. Some first time builders overlook (or just forget or don't know about) the standoffs, and they screw the motherboard directly to the case main plate which causes all sorts of shorts, and the rear IO shield doesn't line up either..... So be sure you're using the standoffs and that they are in the right places. If there's an extra standoff under the board in a spot where it shouldn't be, it will short the board also.