PC will not power up - Techist - Tech Forum

Go Back   Techist - Tech Forum > Computer Hardware > Monitors, Printers and Peripherals
Click Here to Login
Closed Thread
 
Thread Tools Display Modes
 
Old 02-12-2005, 05:57 PM   #1 (permalink)
Newb Techie
 
Join Date: Feb 2005
Posts: 4
Default PC will not power up

I have a PC that works perfectly when running, but when you power it down, it refuses to power up again.
The background is as follows:
After my motherboard got fried (I suspect too muchpower being drawn, frying motherboard connectors), I replaced the modo with a Gigabyte &VM400M-RZ, and the power supply with an Antec SL350P
I friend of mine stripped and re-assembled it all for me.
Now for my problem:
It powers on ok with nothing connected, but refuses to do so otherwise
As the PC belongs to my wife (who shows severe withdrawal symptoms), I left the power on and let her use it.
I then bought her a nice, sparkling new PC, and decided to fix hers once and for all, expecting an earthing problem.
Stripped the case and rebuilt it - no change.
I then removed all peripherals (the Gigabyte has all a basic user needs) and tried again - no luck
I tried the motherboard completely out of the case, then it powered up for me. Drop it back into the case, and it stops powering up.
Where do I start looking next:
A faulty new Antec power supply ??
A new Gigabyte mobo?
A crappy old case?

How exactly should a mobo be earthed (or not).
Should the top of the holding screws be electrically connected to the case (i.e. earthed)?
What about the mobo surrounds of the screws?
__________________

bodo is offline  
Old 02-12-2005, 08:23 PM   #2 (permalink)
Newb Techie
 
Join Date: Feb 2005
Posts: 4
Default

I have been doing a bit more testing....
When shorting out pins on the power supply, it is definitely working.....
so now the motherboard?
Where do I go from here?
__________________

bodo is offline  
Old 02-12-2005, 08:38 PM   #3 (permalink)
Wizard Techie
 
Join Date: Mar 2004
Posts: 3,782
Default

I have known 4 7vm400m, and 7vm400m - RZ motherboards fail. I had one and it developed a intermittant fault and only about 20% of the time it turned on, i replaced it with a Asus A7n8x-x, a friend of mine had a 7vm400m fail, he replaced it with a 7vm400m - rz which also failed. A neighbor had a problem with thier computer not turning on, i looked inside and it was a 7vm400m motherboard. In conclusion, the 7vm400m series are trouble, i suggest getting a Asus, Abit or MSI, they are all good brands.
__________________
Core 2 Duo E6400, DFI Infinity 975X/G, 2x 512mb DDR2 667mhz, Albatron 7900gt, WD 200gb SATA, Samsung DVD-RW, Silverstone ST-50EF 500w PSU.
waynejkruse10 is offline  
Old 02-12-2005, 08:47 PM   #4 (permalink)
Ultra Techie
 
Join Date: Apr 2004
Posts: 858
Default

if it runs when not in case, it's definately a grounding problem, if your running in an old case and you have the spare money, i'd suggest just buying a newer case with better airflow, although i'd still ask around a little more to see if anyone else knows
GageMW is offline  
Old 02-13-2005, 03:52 AM   #5 (permalink)
Newb Techie
 
Join Date: Feb 2005
Posts: 4
Default

Wayne, gage, thanks to both of you
I start believing that the problem is with the mobo.
If I remove the mobo from the case, it works (after a long period that I assume the mobo requires to reset itself) I then add a peripheral to it (such as a IDE channel), and it does not want to know.

As far as the case goes, yes it is old, but it is strong and I had no overheating problems. My cpu was running cool (according to Sandra). I was at one point suspecting the power switch, but I tested it numerous times and it works ok

Thinking back now, when the motherboard and psu were first installed, the solution to switching on was to remove the ethernet cable, then reboot and replace it. This got progressively worse, till all external wires had to be removed, including keyboard, mouse and monitor. In the end it took me hours, and I had no idea what made it work again.

So I willl start looking for an Asus board and try again
bodo is offline  
Old 02-13-2005, 02:51 PM   #6 (permalink)
Wizard Techie
 
Join Date: Mar 2004
Posts: 3,782
Default

Ok, good luck with that.

Wayne
__________________
Core 2 Duo E6400, DFI Infinity 975X/G, 2x 512mb DDR2 667mhz, Albatron 7900gt, WD 200gb SATA, Samsung DVD-RW, Silverstone ST-50EF 500w PSU.
waynejkruse10 is offline  
Old 02-17-2005, 02:36 AM   #7 (permalink)
Newb Techie
 
Join Date: Feb 2005
Posts: 17
Default

Yeah, you should get a new case. Also, keep in mind that some PSUs that i have encountered only power up with all the components attached to it.
firepyro515 is offline  
Old 02-17-2005, 03:59 AM   #8 (permalink)
Wizard Techie
 
Join Date: Mar 2004
Posts: 3,782
Default

only crap generic psu's usually do that
__________________
Core 2 Duo E6400, DFI Infinity 975X/G, 2x 512mb DDR2 667mhz, Albatron 7900gt, WD 200gb SATA, Samsung DVD-RW, Silverstone ST-50EF 500w PSU.
waynejkruse10 is offline  
Old 02-19-2005, 08:21 PM   #9 (permalink)
Newb Techie
 
Join Date: Feb 2005
Posts: 4
Default

Problem solved
After the very useful advice from Wayne and Gage, I have replaced the mobo with an Asus A7n8x-x purchased from Tekheads here in the UK (good service, fast response)
Installed everything (including a complete re-install of Windows - my choice, I am rebuilding from scratch) and it now works like a dream.
I devided not to change the case, as I can see no good reason to do so - My CPU is running at about 50-60 degrees C and the motherboard in the low 30s. I have upgraded the RAM to 1250Mb and replaced a 40Gb disk with an 80Gb that was lying around - I now have 160Gb
Thanks again to all that have contributed.
Cheers
bodo is offline  
Old 02-19-2005, 11:09 PM   #10 (permalink)
Wizard Techie
 
Join Date: Mar 2004
Posts: 3,782
Default

good for you, i have a a7n8x-x, its cheap, resonably fast but doenst have many features, but since i dont have the money to utilise those features i dont really mind (sata, dual channel etc)
__________________

__________________
Core 2 Duo E6400, DFI Infinity 975X/G, 2x 512mb DDR2 667mhz, Albatron 7900gt, WD 200gb SATA, Samsung DVD-RW, Silverstone ST-50EF 500w PSU.
waynejkruse10 is offline  
Closed Thread

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 04:51 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.