Decode Not Enable

[ss205c]

Hello, just swapped out fans on

Dahua NVR5416-4KS2

New fans work, but when nvr starts up I get a black screen with the words "decode not enable" also on the front panel I noticed the hdd light and net light do not come on.

Does anyone have any ideas what could be going on?

 

[alastairstevenson]

Does anyone have any ideas what could be going on?

Maybe a power problem on part of the main board. 2-wire or 3-wire fans?
A simple thing to try would be to unplug the new fans, see if that changes anything.

 

[ss205c]

Maybe a power problem on part of the main board. 2-wire or 3-wire fans?
A simple thing to try would be to unplug the new fans, see if that changes anything.

There are two fans. I unplugged the one which was a 4 wire fan, and I replaced it with a 2 wire fan. The wire colors are red, black, yellow, and blue. I connected the red and black to the new fan but the blue and yellow are disconnected leading to the error message. If I unplug this fan, everything works fine. The fan inside the power supply was a 2 wire fan which I exchanged with a 2 wire fan as well.

So the yellow and blue cable must be essential. When I switched 3 wire fans on my Cisco switch with 2 wire fans, I had to bridge the third wire to one of the other wires or it would throw an error message too. If anyone knows what these wires are for maybe we can figure out if they can just be bridged as well to trick the system to thinking they are connected to something? Any thoughts?

 

[alastairstevenson]

If anyone knows what these wires are for

Rotation speed sensing.
If the system think the fan isn't turning, it will fully or partially shut down as a precaution against damage.

 

[ss205c]

Rotation speed sensing.
If the system think the fan isn't turning, it will fully or partially shut down as a precaution against damage.

Success! The yellow cable is the sensing cable and the blue cable is the pwm cable. I just bridged the yellow cable to the black ground, and the NVR now boots without error.

For anyone who is interested here is how I significantly decreased the fan noise on my NVR5416

1) purchased 2 Sunon HA60151V4-1000U-A99 (these seem quieter than the Noctuas which I used in my Cisco switch)
2) purchase 3m scotchlok connector UY2
3) cut the wire for the 2 wire fan in the power supply, thread the red and black cable on the plug side, and connect to your new fan via the skotchlok (red to red, black to black)
4) cut the wire for the 4 wire fan in the case, thread the red, black and yellow cable on the plug side. Connect the red to red of your new fan, black to black, and lastly insert the yellow cable into the plug of the black cable (not from the pin side)

Result, significantly quieter NVR!

 

[DoubleD_FL]

Thanks for this info ss205c,
I purchased the same NVR but mine gives this error after an unexpected power cut in our neighbourhood. Guess I'll open it up and check for any loose wires or connectors.
If anybody else had this issue - or might have this issue in the future - we'll keep the information flowing in this thread.

In the mean time, a warm hearted thank you to fenderman, nayr, alastairstevenson for their time & knowledge + Andy (Empirecandy) for being a great provider

 

[ss205c]

Thanks for this info ss205c,
I purchased the same NVR but mine gives this error after an unexpected power cut in our neighbourhood. Guess I'll open it up and check for any loose wires or connectors.
If anybody else had this issue - or might have this issue in the future - we'll keep the information flowing in this thread.

In the mean time, a warm hearted thank you to fenderman, nayr, alastairstevenson for their time & knowledge + Andy (Empirecandy) for being a great provider

That sucks! Did you have the NVR on a surge protector? While I got the error message due to the wiring of the fan, I don't believe in coincidence and highly doubt you magically have a lose wire after unexpected power loss. I suspect that error message is a fail safe to keep the NVR from booting for a variety of different issues. Because of the power cut, my first thought would be an issue with the power supply unit. Do all the fans and hard drives turn on?

 

[DoubleD_FL]

Hi again, I got everything up and running again. To answer your questions: yes, the NVR was connected to the power through a surge protector (it wasn't activated though!). But your suspicions might be correct, as the possible 'root cause' is quite silly.
Imagine this:
- power cut occurs
- before rebooting, while the NVR power button was 'off' (on O), I take the opportunity to disconnect the existing blue VGA cable between the NVR and the monitor and hook them up with a new HDMi cable
- ... 'decode not enable' error ...
- I searched on the forum, found this thread
- ... switched back to the old trusted blue VGA cable...
- *magic* the NVR boots up and purrs like a happy kitten

Conclusion: the NVR software is sensitive to all kinds of - seemingly unimportant - hardware changes.
Next step: search a way to change the cable without this silly error.

 

[bigredfish]

Just encountered this on a 32 today. Thankfully found this thread. Swapping the monitor cable from HDMI to VGA fixed it!