Help locating a short

**Disefyl** · 01-14-2009, 04:24 PM

I have a short somewhere in my system. It will shut off randomly whenever the car hits a bump/pothole. I have triple checked all of my connections in my case and everything is secure. I then double checked all of my splices/crimps with no success. Finally I visually inspected the main power cable running from the battery to my trunk but couldnt find any obvious kinks/cuts. Does anyone know of any tricks that may help in locating it. I am to the point of replacing the power cable, but I would prefer not to since routing the cable was a b**** the first time through.

**2k1Toaster** · 01-14-2009, 04:55 PM

Originally Posted by Disefyl

I have a short somewhere in my system. It will shut off randomly whenever the car hits a bump/pothole. I have triple checked all of my connections in my case and everything is secure. I then double checked all of my splices/crimps with no success. Finally I visually inspected the main power cable running from the battery to my trunk but couldnt find any obvious kinks/cuts. Does anyone know of any tricks that may help in locating it. I am to the point of replacing the power cable, but I would prefer not to since routing the cable was a b**** the first time through.

Are you sure it is a short? I had this same thing with my first install. It turns out it was the connector to the PC being loose and also a molex cable's pin had slipped out of its holder.

If you boot into the BIOS, and leave it on some page like the PC Health page or something and drive around, will it restart? If it doesnt restart, then power to the PC is ok. That means usually a HD or RAM problem. Could be loose RAM (not seated 100% correct, or maybe jiggled loose with cheap boards), or the HD connectors for both data and/or power are loose or have a bad connection somewhere between PSU/HD_Power and/or mobo/HD_Data. If windows loses its main HD, it dies and restarts.

So since you already did the checking the cable for shorts and such I think the PC itself is the next logical choice. However to answer your original question, I would specifically check the firewall. Wire through parallel sharp metal can mean trouble if not properly sealed. Other things is maybe have a little light hooked up to your power cable where you can see and then ground the other end. If the light flashes then it got grounded through power and you do have a short. Or a small speaker and when it shorts it will make a screech/scratch.

I know how frustrating that can be, I hope you sort it out!

**duster** · 01-14-2009, 05:08 PM

One other thing that could possibly be a cause that could be a bad cold solderjoint on a chip that might spread when the shock of the bump is hit, mind you it is a stretch but I have seen it on other boards before, just figured I would throw it out there. Personally I would say 2K1's idea of a loose molex is most likely a great idea, I have had that happen and when I was younger I had a 24 pin connector with a loose lug in it(unfortunately I found it the hard way , I moved the wire loom over while running and it destroyed the psu in question after that I had to change my shorts and never had another problem after that)

**Disefyl** · 01-14-2009, 05:16 PM

That was my original thought. I initially believed the problem to be either the sata or power cable for the hd, but after opening the case I realized the problem most likely originated elsewhere. As a precautionary measure though, I used a dab from a hot-glue-gun to insure that neither connector would come loose. I also did the same for the ram. As a final check, I pulled out the pc and powered it from my bench. I picked it up and shook it (probably not recommended), but it remained on.

For the vast majority of power losses, the pc will immediately restart. However, occasionaly it will stall for a short period of time (normally until another sizeable jolt) before powering back on.

Im going to try the light idea to attempt to verify that the issue is indeed a short.

**Disefyl** · 01-19-2009, 11:06 AM

Well I finally gave in and ran a new line to the battery. It appears thus far to have done the trick.

**2k1Toaster** · 01-19-2009, 03:43 PM

Originally Posted by Disefyl

Well I finally gave in and ran a new line to the battery. It appears thus far to have done the trick.

Well with the old line out maybe it will be easier to find the short and tape it up.

**navmaxlp** · 01-19-2009, 06:33 PM

I come across this kind of thing at work all the time. The best way I know of to find something like this is to try and recreate the problem. (This may seem very basic for some of you). I'll try and logically narrow down the possible wires first. For instance, this was a power issue so the audio cables are most likely not the culprit. Then turn on the system and basically wiggle wires to see if you can make it happen consistently. With an issue that occurs when you hit bumps in the road, a good wiggle should replicate the problem. Once you find the bad wire, replace and see if it comes back. Again, this happens at work all the time. I work at an airport on the instrument landing systems. You'd be surprised how often the vibrations from planes taking off and landing causes loose connections.

**Disefyl** · 01-20-2009, 10:50 AM

Thats basically what I did to solve the issue. I was just hoping to patch my main line rather that replace it like I did. Though at least this way I dont have to worry about the solder joints causing the same issue latter on.