The NVR that I use to store my ip surveillance camera video just died. it has been running continuously for 14 months. My experience with electronic equipment that runs 24/7 is that things tend to die in the 3-5 year timeframe. Usually it's the power supply, especially if it's a wall wart. Or with NVRs, DVRs, or network storage, it is usually a disk drive. The unit is an Amcrest NV4108-HS 8-channel HD NVR.
I noticed that the unit was not functioning when I tried to view some recorded video. When I checked it there was no power indication (no LEDs lit, no fan or disk noise). I was hoping that it was just the power supply (12V, 2A wall wart) but unfortunately it looks okay with a resistive load. So, now I'm on to troubleshooting it.
I had initially tested the power supply with a 25 ohm load, so I tried again with a 5.1 ohm load just to make sure it could handle the 2A rated current. The voltage dropped a couple of hundred millivolts but that was probably due to the small gauge wire. So, the power supply looks fine.
I put a DVM across 12V to ground and measured a dead short. The current limit on the power adapter must be protecting the adapter from damage.
Here's a look at the inside of the NVR:
And a closeup of the PCB:
A close inspection of both sides of the PCB did not show any obviously damaged or burnt components. Unfortunately, I haven't been able to find a schematic for this board. I'm pretty sure that it is manufactured by Dahua who is an OEM supplier for Amcrest and many others.
I identified a couple of components that I thought could possibly short the power supply. The first was obvious - a 220uF electrolytic capacitor that is just behind the power jack. I removed it but the short was still there and the capacitor checked out okay. I was hoping to find other electrolytics or voltage regulators (I assume that there is at least a 5V regulator). I did find an adjustable regulator but its input is not attached to 12V. Wish I had a schematic......
I did not pull the heatsink off what I assume is the primary ASIC mainly because I doubt that it would be directly tied to 12V. At this point I think that I may just give up unless someone has any good ideas. Normally, if I had a schematic I would try to push some current into the rail and try to determine where the short is. Without a schematic it would be hard to figure out where to measure. If I felt lucky I could just crank up the current and watch for the smoke but I'm not in the mood to try that.
Unfortunately, I was hoping to use the NVR as a video source for my Path II Programmable project so I need to think about a replacement. The Amcrest unit functioned very well but it is quite disappointing that it had an early death.
At least I should be able to repurpose the case and I'm pretty sure the hard drive is still good - I guess I should verify that next.