Question Troubleshooting a PC that won't power on

[JediKnight]

Opened up my PC to install a new hard drive (more precisely.. to connect a new hard drive.. I had previously installed the hard drive and connected power, but aborted at that point because I failed to realize I didn't have a SATA cable handy 🤦‍♂️). Closed it up, connected everything back up, hit the power switch, and..
..
nothing.

Troubleshooting steps taken:
1. Flipped the switch on the power supply to make sure it was on (duh).
2. Disconnect the new hard drive (both on the drive side and the motherboard side).
3. Reseat cables on the motherboard (in particular for the power switch).

Clues (red herrings?):
1. I have a 3.5" external hard drive connected to this machine. It has a light on the front of it. When the power supply is flipped on, the light on the hard drive turns on.
2. I've had issues with this machine powering itself off. I believed this was due to what I sus is a dodgy hard drive (the plan was going to be to clone it onto the new one.. sigh..)

I did power on one more time during troubleshooting.. but I have not been able to repeat that.

I tried to be careful with ESD safety.. touched the case before doing any work.. but who knows? Mobo did seem to flex a bit when inserting the SATA cable..

 

[In2Photos]

Try disconnecting the power switch on the front panel header and using a screwdriver to short the pins, you may have a bad switch.

 

[ch33zw1z]

re: "clues"

1. unplug anything you don't NEED to complete POST
2. Touching the case before you doing any work is NOT how ESD protection works.

Based on what you're describing, I would make sure you don't have any mobo standoffs out of place. But before you go pulling out a motherboard, both time consuming and not necessary yet.....unplug anything you don't need to complete POST. when in doubt, minimum config.

 

[PCProbs]

The motherboard may have got a shock - removing the CMOS/system board battery might resolve the issue.

 

[JediKnight]

Try disconnecting the power switch on the front panel header and using a screwdriver to short the pins, you may have a bad switch.

I tried this, with no result.
It's possible I didn't short the pins correctly.. I don't have a great workspace, and the case is a bit cluttered in that area (making it hard to see).

 

[JediKnight]

re: "clues"

1. unplug anything you don't NEED to complete POST

Same result, even when the only thing plugged in is literally only the power cord.
Fans don't start spinning.. nothing happens when I press the power button.

2. Touching the case before you doing any work is NOT how ESD protection works.

Isn't it? I was taught touching metal would ground you, and your case is an easy way to do that. Yes, there are the dedicated ESD straps, but they seem overkill?
IDK.. maybe I've been doing it wrong all along..

 

[JediKnight]

The motherboard may have got a shock - removing the CMOS/system board battery might resolve the issue.

Is it sufficient to clear the CMOS? The battery is obstructed by my video card, so I'd have to remove it to do this..

My mobo manual has this:

CLRCMOS1 allows you to clear the data in CMOS. To clear and reset the system parameters to default setup, please turn of the computer and unplug the power cord from the power supply. After waiting for 15 seconds, use a jumper cap to short pin2 and pin3 on CLRCMOS1 for 5 seconds.

Would this do the job?

 

[ch33zw1z]

Same result, even when the only thing plugged in is literally only the power cord.
Fans don't start spinning.. nothing happens when I press the power button.


Isn't it? I was taught touching metal would ground you, and your case is an easy way to do that. Yes, there are the dedicated ESD straps, but they seem overkill?
IDK.. maybe I've been doing it wrong all along..

1. ESD - Electro Static Discharge - I'll attempt to explain . This is what you don't want to happen. If you and the device are at different charge levels then the potential difference can be a problem, you run the risk of discharging electrical current from yourself onto components in your case. The most used example is lightening, as this is the same thing happening, so think about that when you walk across a carpet and touch a door knob, or your case, and feel / see that spark…except with technology, there’s no need to see or feel any “spark” to be discharging static electricity onto components

PC components run at very small direct current voltages, so even minimal amounts can cause damage over time...if not immediately. The worst part about ESD damage to our technology is how it rarely kills stuff outright, but instead weakens components which in turn causes intermittent problems. Problems like that may be resolved by reseating components, or reboots, stuff like that.

What the goal is with ESD protection / prevention is to minimize potential difference between you and your case. This is where a wrist strap comes into play, because when it's in working order then charge can flow between you and the case.

A couple points though:

a. Do NOT keep the power cord to the wall plugged in while using an ESD protection wrist strap.
b. It's best to find an unpainted metal surface of the case to attach the wrist strap to, but that's harder and harder to find on home PC cases as most of the case is painted / powder coated.
c. Best practice is to touch another metal surface before touching the case / putting on the wrist strap.


2. Ok - onto your problem - Keep in mind, you only need the CPU, a DIMM, and a VGA of some kind to complete POST.

Same result, even when the only thing plugged in is literally only the power cord.

So is this really the case? Because if so, then you will need to leave the speaker connected, and pull either the VGA out or the Memory DIMM's. You goal now is to see if removing either of those causes the system to POST error out. If it does, that's a good thing....it means the motherboard is still alive.

If you pull the VGA and DIMM's out, and still get no POST error, the board is probably toast.

Side note, you can pull the CMOS battery for any of this as well, you will lose any saved settings in the BIOS which doesn't really matter if the mobo is dead anyways.


edit: background - I have been into technology since 1999. I too was taught wrong AT A SCHOOL that I paid to go to. It wasn't until I got a job at a big ole corp that was a tech corp and took ESD very seriously, that I learned what ESD was and how / why we want to prevent it. So no worries here dude!

 

[PCProbs]

If the motherboard got a shock removing all power sources (including the CMOS battery) should revert all electrical components back to their default state.

Removing the CMOS is often used to resolve firmware/BIOS glitches, however in this instance we are using it to clear all current from the system.

 

[JackMDS]

You disconnect everything from the Mobo and the PSU. Take it out of the case put on a table (not a metal table) plug the PSU, Memory, and GPU. Connect the GPU output to a Monitor, Plug the PSU to an outlet, and the PSU output to the Mobo.

Look at the Mobo manual and find where are the two pins that the front Panel plugged to switch on. Switch On the PSU and use a screw driver to shorter for 3 sec. the two Power pins.

Example: The Short would be between PW and PW+ (left side down).

If it does not start get a PSU Tester (about #12 on Amazon). If the CPU tests OK you need a New Mobo.

If it is working on the table, then some thing is wrong with the Case wiring, or and switches.

Good Luck....

 

[JediKnight]

Have to put this on the back burner for a bit.. priorities.. sigh.
When I said I "unplugged everything" I meant externally.. I haven't gone and started pulling out components from inside the case.. yet. Ripping apart my machine and putting it back together isn't a project I'm looking forward to (and I hoped to avoid it).

In the mean time.. I am interested in getting a PSU tester. Which ones are decent? I see lots of stuff (junk?) on amazon by companies with (randomly generated?) names I've never heard of before, that look basically identical from photos. I don't want to buy something dodgy.. if you have to question whether your testing equipment works, well, you're not in a good spot..

 

[ch33zw1z]

You don’t have to rip it all out, yet. Just disconnect power and data for anything you don’t need to complete POST.