Help with my Dell Dimension 4600

[sparky0173]

I was hoping to get some advice from the helpful folks at AnandTech in trying to figure out what's wrong with my computer.

I have a 3 year old Dell Dimension 4600 that stopped working the other day. It was working fine most of the day, but when I tried to turn it on later in the evening nothing happened. No noise, no power up... nothing. I cracked open the case and made sure everything was plugged in and secure. There is a little green LED light on the motherboard that still lights up when the computer is plugged in so I think the power supply is still working.

Any one here have any idea what could be wrong? I have a suspicion that it could be the motherboard or some kind of defect with the power switches, but I don't know of anyway to tell. The computer does everything I need so I'd hate to just toss it away if there is a simple fix.

Any advice anyone could offer would be greatly appreciated! Thanks in advance!

 

[montag451]

Hi,
Its hard to say exactly what it could be, but if you are lucky, it might just be that the power button might be broken,

 

[LiLithTecH]

On the back of the PC there is a row of 4 LED's.
What color are they going from left to right (amber or green)?

 

[sparky0173]

The LED's on the back of my computer are not lighting up at all, not even when I press the power button.

I think I ruled out power switch failure by using a jumper on the two electrodes where where the power switch wires lead to on the motherboard.

Any one else have any other ideas?

I wouldn't mind replacing the motherboard or power supply if it's likely that those are the only parts that are damaged. But if the CPU was also damage, it's probably cheaper for me to buy a new computer.

 

[RebateMonger]

I had an IDENTICAL client's Dimension 4600 with IDENTICAL symptoms. It was the power supply. Dell first replaced the motherboard (against my own recommendation). When that didn't fix the problem, Dell replaced the power supply. That ifxed it.

The green light was lighting on my client's motherboard, too.

 

[LiLithTecH]

Yes it is the Power Supply.

The Dimension 4600 was one of the systems affected with
a PSU with bad capacitors.

If you remove the PSU and open it up you can confirm it for yourself.

 

[mobobuff]

Try "jump starting" the PSU by unplugging the ATX connector (the big one) from the motherboard. Make sure the PSU is plugged in and the rocker switch is in the on position. Get a paperclip and bend it into a horseshoe. Now just jump the PS_ON (the green terminal) and any COM (a black terminal) leads.

Here is a pinout diagram to show you. If you do this and the PSU kicks on (fans will start and you'll hear the hard drive spin up) then it's the motherboard. If the PSU does nothing, it's the power supply.

I'm guessing it's the power supply.

 

[sparky0173]

Thanks guys for all of the replies! They have been very helpful!

mobobuff, I tried jumping the PS as you suggested and the power supply fan started to spin. I guess it's the motherboard!? I tried looking on the motherboard for any blown capacitors, but couldn't really find any. At this point, is there any way I could tell that it's the motherboard rather than the CPU that is damaged? I guess the fact that it's not posting the bios screen would suggest that it's more motherboard than CPU.

From what I could tell, the Dimension 4600 uses a micro ATX board. Can anyone confirm that? Will I be able to replace it with any micro ATX board or does Dell have proprietary board and case configurations?

Thanks in advance!

 

[brett42]

I've seen a lot of Optiplex 270 power supplies with the bad capacitors that seemed to work normally except for the 5v standby power running at around 3.5v, so the light on the motherboard would go on, and they were stable if you managed to get them started, but there usually wasn't enough power to get the motherboard started. If it's possible to test it out with a new power supply, I'd try that first.

 

[sparky0173]

Brett42, are you saying that some of the capacitors may have blown out, but the power supply is not completely dead?

I'll try to open up the power supply and see what's going on inside.

As far as replacing the power supply, will any ATX PS work? Do I have to get the 12V ones? I don't have a whole lot running inside the computer (2 CD-Rom drives, 1 HD, 1 video card, 1 sound card, and a tv tunner).

Thanks!

 

[montag451]

Are Sparky and Brett brothers?

You do get different ATX psu's, but most are standard size. BUT, anything to do with Dell, I would measure the h x w x d and check this against the new psu spec.

 

[brett42]

In the Optiplexes I've seen, the early stages of capacitor problems just seem to effect the standby power, but the 4600 power supply could be different. It looks like the 4600 is one of the few Dimensions from that period to use standard power supplies, so any brand should be ok. I think ATX 12V is where they introduced the 4-pin connector you need for Pentium 4s, but anything made in the last few years or p4 compatible should work.

 

[imported_mingus]

Yes the 4600 uses a regular PSU. I put in an Antec and works fine. bought a new case, but the CPU fan and front I/O connectors all all weird of course. Anyone know how to hook these up or have a pinout? the Dell manual does not.

http://support.dell.com/suppor...0/en/4600/sm/index.htm

 

[jtbrown57]

I had the exact same issue with the Dell Dimension 4600. After much reading and finding this thread I replaced the PSU hoping that the MB had not been effected. I bought this PSU from Newegg.com. Popped it in and the computer started right up perfectly. Thanks for posting and the main reason I wanted to append to this is to say that it actually did fix the problem.