Troubleshooting Help

[-SeanS]

I have a Sony VPCL13S1E that I am trying to troubleshoot. The PC turns on however it does not POST, no beeps or anything, the display is blank and nothing is shown. I have had a look at the motherboard and tried various things such as replacing bios battery checking all connections etc. I have found that when powered up some of the fans are running however the CPU fan does not start up, is this normal? I know some fans are set to only kick in when the CPU gets up to temp could this be the case? Anyway, this tells me that the MB must be getting power, also, I have tested the HDMI In, and it still functions as a TV, does this mean the graphics card still works or is this a totally separate thing?

Thanks for your help

 

[Yevrag35]

So I take it you didn't get that new motherboard or scraped it for parts? (FYI for anyone wondering http://www.techist.com/forums/f77/identifying-ram-265048/)

If the HDMI works, the GPU is most likely not at fault. Does the screen even look like it's turning on at all but just no picture? You checked the connections from the screen to the motherboard?

 

[-SeanS]

So I take it you didn't get that new motherboard or scraped it for parts? (FYI for anyone wondering http://www.techist.com/forums/f77/identifying-ram-265048/)

If the HDMI works, the GPU is most likely not at fault. Does the screen even look like it's turning on at all but just no picture? You checked the connections from the screen to the motherboard?

To be honest I thought I'd hold of a little because I'm intrigued as to what exactly is wrong, I was just going to keep an eye out for a machine that has a smashed screen or something and maybe I could take the MB from that, but if not I'll sell for parts. But for now I just wondered if there was a way to find out exactly what is at fault here, I only checked the main connections really so I'll see if I can locate the connections for the screen to MB, what do you think about the CPU fans not running, is this normal? My initial thought was maybe these broke in the past, causing the CPU to overheat or the northbridge chip?

Thanks

 

[Yevrag35]

If the CPU fan is not running, then that's a problem.
Is there another 3 or 4-pin fan connector that you could try the cpu fan on?

If the fan runs connected to other fan connectors, then you know what the problem is. If not, that fan/heatsink has to be replaced.

That is the one fan you NEED running.

 

[-SeanS]

If the CPU fan is not running, then that's a problem.
Is there another 3 or 4-pin fan connector that you could try the cpu fan on?

If the fan runs connected to other fan connectors, then you know what the problem is. If not, that fan/heatsink has to be replaced.

That is the one fan you NEED running.

Ill give it a try and get back to you, I have another CPU which is compatible with the system, would it be possible to try this to see if I get anything or would the CPU burn out very quickly without the fan running? Thanks

 

[carnageX]

Check to make sure RAM is seated securely.

Try individual sticks one at a time.

There may be a RAM stick under the keyboard as well (common for laptops), as well as under the bottom-access panel.

 

[-SeanS]

Thanks for your comments, I've tried all the above to no avail. I tried the CPU fans in another 4pin connector for the PSU, the fans looked like they tried to start (spun for a second) then went off again. The PSU fan does connect to motherboard and power up fine however. Could it be that power is somehow not reaching the fans on the other end of the motherboard? It does look to me like it is the northbridge chip that is at fault after all. Do these sound like symptoms of a northbridge failing? It's frustrating that no matter what the screen is literally dead, it doesn't give me any indication that anything is happening at all.