Looking for some of the experienced PC techs out there to help figure out what to try next.
A friend of mine complained that his PC will not display anything when they turn it on. The LEDs light up but that's about it. They checked cables and all and everything appears tight but the monitor only displays 'No signal'. They brought the PC to me to see if I can get it to work again.
I hooked up their PC to my monitor and I experience the same problem. At first I thought it was a video card / port issue but it seems to be something else. The system is an HP Pavilion A1610N using the built-in video adapter of the A8M2N-LA motherboard. I've tried connecting the PC using just the built-in video adapter and connecting my own nVidia PCI-E video card with no change. Here's what happens when I turn on the PC using built-in or using the nVidia PCI-E card:
- Power light comes on
- CPU heat sink fan turns on
- Tower fan turns on
- DVD light flickers
- No display on monitor
- No HDD LED activity
- No Keyboard LED (No Num Lock, Caps Lock, Scroll Lock lights)
- No optical mouse light
- DVD still responds when pressing 'eject' button
It doesn't appear to be a PSU / power problem. There is just no display (not even BIOS sequence). I feel it's something other than the video adapter since I've tried my own working nVidia PCI-E with effect. I've also tried putting in an Ubuntu bootable DVD prior to turning the system ON with no change. I've also tried connecting the USB keyboard and mouse on various USB ports but the keyboard and optical mouse never receives power.
I've took out the RAM and firmly locked it back in place. I've removed the heat sink and CPU to check if there are any signs of a damaged CPU (no obvious signs of burnt / damaged CPU) and firmly put it back in place. I've removed the SATA connections and firmly put them back in place. In short, I've made sure that all internal / external connections are firmly attached with no obvious signs of damage.
I've removed the heat sink and CPU to check if there are any signs of a damaged CPU (no obvious signs of burnt / damaged CPU) and firmly put it back in place.
Did you clean off the old TIM and apply new TIM when you took the heatsink off?
It does to me. Why don't you think it does? Understand a PSU must provide 3 voltages; +12V, +5V and +3.3V. If any one is bad, your system will not boot. Most lights and fans work on 12V. CPUs, USB, RAM and other motherboard devices need +5 and +3.3V.
When troubleshooting hardware, I always start at the wall. I would have that PSU tested, of if you have a known good one that is compatible with that PC (not a given with older Dells), swap that in.
It does to me. Why don't you think it does? Understand a PSU must provide 3 voltages; +12V, +5V and +3.3V. If any one is bad, your system will not boot. Most lights and fans work on 12V. CPUs, USB, RAM and other motherboard devices need +5 and +3.3V.
When troubleshooting hardware, I always start at the wall. I would have that PSU tested, of if you have a known good one that is compatible with that PC (not a given with older Dells), swap that in.
Digerati, not to derail this post but I need an answer to a question about power supplies, I checked a lot of them because being a manager of a local power plant, I know how bad we have voltage spikes, brownouts, lighting hits and so forth. While testing a lot of PS I have found the negative leg of the 5 volt side bad (some calls them rails) so I been replacing them with new ones.
But many local techs here in town told me nothing is using the 5 volt rail or if the negative leg is out does not affect nothing and if the machine is working then its no need to replace the PS. I kinda disagree in this matter but never could back that fact up. But being a electrician when ever something is going out, its sure to cause further problems.
I have found the negative leg of the 5 volt side bad (some calls them rails) so I been replacing them with new ones.
But many local techs here in town told me nothing is using the 5 volt rail or if the negative leg is out does not affect nothing and if the machine is working then its no need to replace the PS
The ATX Form Factor Standard specifies the required voltages and tolerances. While the -5VDC tolerance is still specified, note on page 22, Table 6, it has the comment "if used" next to -5VDC. The fact of the matter is, those technicians were right. ATX compliant PCs (representing the vast majority of Windows based computers) do not use -5VDC as noted in the tolerances chart below, and those supplies did not need to be replaced.
[external image: Posted Image] NOTE: Disregard the -5VDC reading. It is no longer used.
…being a manager of a local power plant, I know how bad we have voltage spikes, brownouts, lighting hits and so forth.
Which is exactly why for years I have been urging all computers be on a "good" UPS with AVR. And I appreciate you specifically mentioning brownouts as it is necessary to note that surge and spike protectors do absolutely nothing for low voltage events likes dips (opposite of spikes), sags (opposite of surges) and brownouts (sags of longer durations). For that reason, surge and spike protectors are little more than fancy and expensive extension cords. And note I said, "good" UPS with AVR. Like power supplies, there are cheap models you should avoid. And note backup power during a full power outage is just the icing on the cake. It is the automatic voltage regulation provided by the AVR voltage regulation circuits using the robust absorption properties of the batteries that makes UPS with AVR so important.
The fact of the matter is, those technicians were right. ATX compliant PCs (representing the vast majority of Windows based computers) do not use -5VDC as noted in the tolerances chart below, and those supplies did not need to be replaced.
Well then it settles that, no longer replacing the 5 v - leg anymore.
…being a manager of a local power plant, I know how bad we have voltage spikes, brownouts, lighting hits and so forth.
We did this to save during peak demands during the summer
Which is exactly why for years I have been urging all computers be on a "good" UPS with AVR. And I appreciate you specifically mentioning brownouts as it is necessary to note that surge and spike protectors do absolutely nothing for low voltage events likes dips (opposite of spikes), sags (opposite of surges) and brownouts (sags of longer durations). For that reason, surge and spike protectors are little more than fancy and expensive extension cords. And note I said, "good" UPS with AVR. Like power supplies, there are cheap models you should avoid. And note backup power during a full power outage is just the icing on the cake. It is the automatic voltage regulation provided by the AVR voltage regulation circuits using the robust absorption properties of the batteries that makes UPS with AVR so important.
This is why I push UPS real hard with a AVR, which I have here in my shop.
For that reason, surge and spike protectors are little more than fancy and expensive extension cords.
Yep and many folks think this is protecting their computer's, TV's, Stereo's and so forth, in fact it does nothing but make money for for the folks who sells them.
And why I have a good UPS with AVR on my big screen TV and home theater audio equipment too.
We did this to save during peak demands during the summer
A common practice, sadly. I should point out that not all power anomalies come from the power grid. Any high wattage appliance in the home or office (oven, microwave, hair dryer, toaster, water cooler, refrigerator, coffee pot, etc) can dump abnormal anomalies on the circuit. Of course they are not supposed to, but stuff happens. And sadly, many folks simply refuse to believe, or choose to ignore the fact that things fail, break and go bad. Sadly, as more and more manufacturing is out-sourced to 3rd world countries, many of these products are produced where the working conditions, factories, training, quality control, are all questionable at best. In some cases, even the age of the labor force (often forced labor) may be questionable. And to compound the issue, these products are often being built using parts supplied by similar factories up-river.
I wonder how safe a $15 1500W hair dryer is after it has been bounced once or twice on the counter? Scary!
Thank you all for the valuable input. I'll try working on this PC again tonight or over the weekend. The problem is they brought only the tower with no power cables, keyboard, or mouse (not that the keyboard and mouse mean anything at this time). I need to take down my own system when troubleshooting
@terry1966: I'll try to verify if the internal speakers are connected as I don't hear any beeps during my testing. Thanks for providing the link to the beep codes.
@Nahumi: Removing the heatsink / CPU was a last resort to get any response from the system. I have not replaced the thermal compound yet. I put it back really firmly and carefully though ( ) Once I get the system to at least display something on screen then I can move into additional troubleshooting if the system is unstable at that point.
@Digerati: Thanks for providing info on PSU voltages.
Most lights and fans work on 12V. CPUs, USB, RAM and other motherboard devices need +5 and +3.3V.
It would appear that there might be a problem with the PSU given this info. What I'd give to have an old computer lying around for spare parts (especially a working old motherboard and PSU to test components on). I guess I'll have to check the local flee market or Craigslist for old working PCs (or use my own PSU and see if that works).
I find it a privilege to help my family and friends with their computer problems but when it comes to computer surgery, I'm quite lacking in tools
Removing the heatsink / CPU was a last resort to get any response from the system. I have not replaced the thermal compound yet. I put it back really firmly and carefully though ( ) Once I get the system to at least display something on screen then I can move into additional troubleshooting if the system is unstable at that point.
Before you go any further, you really need to replace the TIM. The minute you take it off you're introducing air between the heatsink and the CPU. No matter how hard you press it back, you won't get rid of all the air pockets. These air pockets will become little insulating bubbles, meaning that the CPU will be unable to properly dissipate the heat.
To be honest, I think your only option is to check each component on your own system. Go through everything, that means PSU, RAM, CPU and Mobo (If you can), even the CD/DVD drive and just check it on a known working machine. That's the only way you'll be able to track down exactly which component is causing the trouble.
It is not just air pockets, TIM - thermal interface material - cures after it has gone through a few heat up/cool down cycles. So even if you could get all the air out, which I doubt, the thermal transfer properties have been compromised. So ANY time the cured bond between heatsink and CPU mating surfaces has been broken, you need to thoroughly clean the old TIM and apply a proper layer of fresh TIM.
) Once I get the system to at least display something on screen then I can move into additional troubleshooting if the system is unstable at that point.