Dimension 4550 Power-on problem

Question

I have a Dimension 4550, 533 FSB, BIOS version A03.  Recently it's been difficult to power it on.  If I turn it off and don't unplug it, it seems to power on fine.  However any time I unplug it, either to move it somewhere else or add RAM or whatever, it won't immediately power up after plugging it back in.  I can hit the power button on the front several times but there won't be any response (the button does not appear to be stuck or anything; I checked).  As soon as I plug it back in, I can tell that there is current going through the system because the network jack LED flashes continuously, communicating with my cable modem.  But other than that it's silent.  I'm used to hearing a quick fan-on sound and maybe seeing the three keyboard green lights flash briefly after plugging it back in, but it doesn't do that any more.   The symptom is that I plug it in, and have to wait about 2 minutes before it just spontaneously starts up and boots.  No errors on boot or anything.  Pressing the power button does not do anything during the wait time, and the system is completely silent until it just powers on by itself.  While the computer is on, it runs flawlessly up to days at a time as long as I don't shut it off and then unplug it.  I tried a different power cable, cleared the NVRAM via BIOS (Alt-E Alt-F Alt-B routine), tried different power outlets, but the same thing always happens after it's been unplugged.  Interestingly this didn't start to happen until right after I added a Maxtor external hard drive via USB port on the back.  But I have tested it without anything in the USB ports aside from the mouse, and just the basics connected: mouse, monitor, keyboard, power cable (*no* network cable).  The same behavior occurs.  I've had it for 3 years of heavy use (it's powered on most of the time).  I should probably add that I bought it refurbished through Dell Home when it was still the current model.  Or maybe they had just introduced the 4600?  It was January '03 in any case.   Has anyone ever seen a problem like this?  The system sounds pretty much just like it did on day 1; no unusual fan or power supply noises.  Nothing was changed internally between the time it was working and the time this started happening.  Thanks for your help!

osprey4 · Answer

I suggest when it fails to power up, pull the plug, hold the power button for two seconds to discharge capacitors, plug it back in and power it up again. You may have a power supply problem, but if this work-around takes care of it, I wouldn't worry about replacing the PSU.

gigoloju · Answer

osprey4,

Thanks! I tried your method of discharging the capacitors and it seems to work. I tested it, and if it's been unplugged for a few minutes rather than seconds, I have to repeat the procedure a couple more times before it powers on, but it does so much sooner. If it is the PSU, do you think it may be on its way out? I am still under the extended 3-year warranty but I don't want to go through a lot of irrelevant testing via phone support, and having to be at home during the day for the NBD service. I actually have an email thread started with Dell support about this problem since yesterday, but they've told me some irrelevant stuff thus far (they suggested following a link to Windows XP OS startup problem troubleshooting, not hardware power-on problems). Maybe I can convince them to ship me a new PSU under warranty and do it myself, if it's not a difficult procedure to replace it in the 4550. I've replaced a few PSUs on Gateways in the past without much difficulty.

osprey4 · Answer

Keep up the e-mail contact with Dell to get a  new PSU as long as you're under warranty. The replacement is straight-forward.

gudgeon · Answer

My 4550 (of the same vintage, Jan 2003) has never shown this problem (talk about tempting fate!) but I've had these same symptoms with two other non-Dell PCs when following Osprey's procedure of holding in the power switch has got me booted up. In both cases, replacing the power supply solved the problem.

gigoloju · Answer

Thanks guys.  I'll get after tech support to send me a new PSU under warranty, as that is clearly the problem.  Other than that, I couldn't be happier with my 4550 over the 3 years!  It doesn't even feel obsolete or slow at all at this point.  Wait until I try to put on Vista, though...  if I even bother.  At least 1 year after it gets officially released to give it time for the worst initial bugs/security problems to be fixed.

prometheis_7806 · Answer

I too have these symptoms for the past 2 weeks on my 4550/N380 non PFC power supply. I rarely use the system, 1/week for an hour, no upgrades except memory 2 years ago.  I too will try the work around.  Dell chat had me check to see if the motherboard lights when power is pushed (it does), fan on power supp. works. No error messages or probs bringing up system.  Once PC is turned on I can power up/down all day long no probs. Prob exists only after sitting for 12 hours or so....any other comments?

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Dimension 4550 Power-on problem

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