Inspiron 545 MT startup problem

[martiantimeslip]

I have a problem when starting my PC when it has been switched off at the mains for a while.Powered on at mains, green LED next to mains plug is on.Push On button, once, twice etc etc no startup.Took off side of minitower case, orange LED on motherboard glowing. No fans active (that is PSU, case , processor).Pushing the On button causes the case fan to give a little twitch (less than one turn), holding the on button down causes the case fan to twitch at second intervals. Tried this several times over the course of a few hours, no startup, finally on one push processor fan starts and whole thing boots up normally.
So some kind of start up problem, but whether its the PSU or the motherboard, I've no idea. I am an EE and have DC probe capability but would appreciate help from anyone who knows how the startup process works on the Dell or indeed any other similar system. Its 2 years old so well out of guarantee.

Best Regards

 

[Ubrales]

Sounds more like an "ON" switch problem. Can you take this switch out and then manually 'short' out the start terminals to simulate depressing the start switch?

 

[martiantimeslip]

No its more complicated than that. The ON switch is fine, I disconnected it and measured the resistance, its zero when pushed. I can also get the power supply to start up by shorting the PSON wire in the 24 pin power connector to ground all the fans including the processor fan are running,the PSU output measure OK, but the processor hasn't booted and the ON switch LED is orange rather than white. That supposedly means the processor is in a sleep state, but it won't come out of that state with keyboard or mouse activity as it should so I don't think that is valid. What I need is someone who knows the circuitry and sequence that follows pushing the ON button, to try and figure out the problem. I've downloaded a motherboard manual but you don't get that much detail.

 

[TheAce]

Hello,

Have you found the potential Issue? I have the same exact behavior although i do not know much about how to short circuit it safely to know if the PSU starts.

Basically, when pressing the power button it shows the "oragne light and goes off" and the fans just do a small little turn.

After many tries of unpluggin the PSU / waiting/ pluggin the PSU back then pressing button its either orange and sometime it works and boots up normally.

Unfortunately, yesterday after reboot after an usual "5 minutes" usually i get it working but i couldn't last time.

Let me know if you have found what was the potential issue....

 

[martiantimeslip]

Yes, I solved the problem by changing the power supply. After a lot of chasing around, you'll see my post on several other sites, and not getting any real solution, it came down to either a motherboard fault or a PSU fault. If it was a mother board fault it would be virtually impossible to fix so I decided to take a chance on a new AT PSU, details are below. The optical and hard drives in my Dell use the newer SATA power connector rather than the Molex one, so you need the converter also shown below. One thing that convinced me it was the PSU and may help you, was that I only got the problem if the computer was off for quite a while, so I wondered if it was a temperature issue. I directed a small fan heater at the PSU for 5 minutes, just to warm it up a bit and both times it started first time after this treatment. I didn't try it enough times to say it was definitely a temperature problem, but it did make me think it was worth trying a new PSU - which proved to be correct.

http://www.amazon.co.uk/500-WATT-ATX-POWER-SUPPLY/dp/7135799313/ref=sr_1_1?ie=UTF8&qid=1318860014&sr=8-1

https://www.amazon.co.uk/Molex-to-2-SATA-Internal-Power-Splitter-Cable/dp/B0002GRUV4/ref=sr_1_1?ie=UTF8&qid=1318860122&sr=8-1

Best Regards

 

[TheAce]

That was my first though also that it was a PSU Problem. But just because as you state there are many thread with that same exact problem but no solution, i though that since this post was quite recent you would still be around

That confirm me of getting a new PSU and try it out. As for the SATA Power connector i think they were normal SATA Power connector but thanks for the information i'll check in case the molex one in case.

 

[martiantimeslip]

The Molex / SATA connector problem only applied to that specific power supply, which only had one SATA power connector and my Dell needed two - your PSU may be different. Let me know how it works out.

Best Regards

 

[cobradon]

If windows 7, Go to control panel, power options, reset sleep mode to "shut down" or "do nothing"
Similar process for Windows XP but may have different options. Do not select "sleep mode"

No its more complicated than that. The ON switch is fine, I disconnected it and measured the resistance, its zero when pushed. I can also get the power supply to start up by shorting the PSON wire in the 24 pin power connector to ground all the fans including the processor fan are running,the PSU output measure OK, but the processor hasn't booted and the ON switch LED is orange rather than white. That supposedly means the processor is in a sleep state, but it won't come out of that state with keyboard or mouse activity as it should so I don't think that is valid. What I need is someone who knows the circuitry and sequence that follows pushing the ON button, to try and figure out the problem. I've downloaded a motherboard manual but you don't get that much detail.

 

[mobiyob]

WEIRD! Okay, I'm working on an Inspiron 545 with same problem: pushing the button once will cause the case fan and the psu fan to spin a little but no boot.

I have tried switching out the original PSU with a used PSU from my closet and still same problem with the fans turning a little. So I am skeptical about purchasing a new PSU. Will a new PSU fix this problem? Very odd.

THOUGH: The computer will turn on if I hold the button down while jiggling. and sometimes after the computer has been on for a while it will boot up with one simple push of the button. But only rarely.

Does anyone know what the true problem is here? Martiantimeslip says new PSU will fix this, that the problem is a faulty power supply... Well, I'll give it a go and purchase a new one, but am curious if in fact it is just the power switch. face palm

Aloha




UPDATE: Installed "NEW" Power Supply and now powers on. Had to hold the button down and it made three or four "fan-nudge/spin" noises then powered on successfully twice. Now it powers on normally with a regular push.

Solution: get a new PSU for the Inspiron 545

 

[Ubrales]

What I need is someone who knows the circuitry and sequence that follows pushing the ON button, to try and figure out the problem. http://www.uklv.info/g.gif

It is on a mini PCB and I don't think Dell will disclose such circuitry information.

 

[Mousemonkey]

Best answer selected by mousemonkey.

 

[Mousemonkey]

This topic has been closed by Mousemonkey