Repairing a completely dead Hikvision NVR DS-7616NI-K2 – A while ago, I received a WhatsApp message from a customer reporting that their Hikvision NVR had stopped working. I went to the site to check the issue and found that the unit showed no signs of power. After explaining the situation, I asked for permission to take the NVR for further inspection, and the customer agreed.
This article is based on a real case study in which we resolved a Hikvision NVR issue where the adapter LED turned off when plugged into the unit.
What Causes a Power Adapter to Shut Off When Connected to an NVR/DVR?
That evening, after returning home, I performed a thorough inspection of the Hikvision NVR and confirmed that it was completely unresponsive. The adapter LED turns off as soon as it is connected to the device. There are several possible reasons why a power adapter LED turns off when connected to a DVR/NVR.
Modern adapters are designed to shut themselves down if something’s wrong, like:
- Too much current draw (overload)
- A short circuit
- A failing device pulling power incorrectly
TVS Diode Faulty, DVR/NVR PCB Circuit Safety Protection
After a thorough inspection by opening the NVR, I finally found the main cause of the adapter LED going out when connected to the NVR/DVR—namely a faulty TVS diode.
A TVS (Transient Voltage Suppressor) diode is designed to protect a circuit by clamping voltage surges when the input voltage exceeds safe levels (typically above 12V in a 12V system). For example, a Hikvision NVR operates at 12V. When a voltage surge occurs, the TVS diode responds by absorbing the excess energy to protect other components on the PCB. However, if the surge is too strong or repeated, the TVS diode itself can become damaged.
Below is a photo of the damaged TVS diode that I took during inspection of the Hikvision NVR.
Fixing the Adapter LED Turning Off When Plugged Into DVR/NVR
At this point, the NVR requires repair.
Since this issue involves technical electronic components, we recommend having relevant knowledge before attempting any repair. If you are not experienced with electronics, it is recommended to consult a qualified CCTV technician to prevent further damage.
Steps to replace the TVS Diode on a Hikvision NVR.
Requirements
- New TVS Diodes
- Solder Iron with a minimum voltage of 60 Watts
- Solder Wire
Step-by-Step Instructions
Step 1 – Open the NVR cover.
Step 2 – Remove all screws and carefully take out the PCB.
Step 3 – Heat up the soldering iron.
Step 4 – Apply the soldering iron to the TVS diode leads until the solder melts, then carefully remove the diode using tweezers. Install a new TVS diode in the same position and solder it securely using solder wire.
Conclusion
If you experience issues such as a DVR/NVR not powering on or the adapter LED turning off when connected, you may follow the steps provided above. However, since this repair involves electronic components, we recommend seeking assistance from a qualified CCTV technician if you are not experienced in electronics.
This article covers the troubleshooting process for an adapter LED that turns off when connected to a DVR/NVR. We hope it helps.