Dahua XVR slowly not displaying analog cams

[imnozi]

I have a Dahua XVR (32 total IP+analog cams, 24 analog BNC ports). IP cams attached to it are OK.

Recently, it appears that analog cameras are failing; just black display on the NVR/web/SmartPSS. But the cameras have power; I can see the LEDs and sometimes hear the internal relay click when it switches between light and infrared. The old wall-mount power supply (18 ports) is OK, producing 12.5VDC. A couple cables I checked show 12VDC at the camera end (can't yet check voltage with camera plugged in). One 'failed' camera works OK in another BNC port, so it might not be the cams. I power-cycled the XVR and more ports failed to work.

I'm starting to suspect that analog ports on the XVR are failing. But I haven't opened the XVR to check inside yet; it could be filthy inside or its internal power supply could be on its last legs.

Has anyone encountered this problem on Dahua XVRs (or any other brand XVR for that matter)?

Tbanks,
Neal

 

[TonyR]

Are any of those "failed" cams using the baluns you mentioned in your other post?

 

[bigredfish]

Could be baluns, connections, did you recently add cams? More likely there is a limit as to power output and processing power on XVRs just like NVRs. You may well be maxed on output.

I recall in the early XVR days where I had to downscale FPS and/or bitrate on analog cameras similar to IP cams to get all to display.

Unplug your analog cams or temporarily disconnect the switch running the IP cams and add back one at a time giving each a few minutes.

Or try taking all of your analog cams down to 15fps and 6144 bitrate (yes on analog XVRs FPS matters as to total output)

 

[imnozi]

Oh, duh; I forgot that. Cams are all at 7 FPS. The cams were all working when I installed the XVR, and did work for 2-3 years. Granted, some of the analog cams are 8-10 years old, but that shouldn't be a problem. Unless there's been lightning damage.

Another oddity. When using the console and switching to camera settings, it can take .5 to 1 minute for the image to display (for analog cams that are working). I really hope I don't find any swollen caps when I open it up.

 

[bigredfish]

Yeah, could be old age and surges over the years finally caught up. But if you e recently added cams, I’d look at total output first.

 

[MC1987]

What is model of XVR? Do you see red ? icon on the bottom left of channel on local monitor? Any messages in the live view of local monitor?

 

[imnozi]

Are any of those "failed" cams using the baluns you mentioned in your other post?

Sorry. Overlooked your post.

No, I replaced one with an IP cam thinking I could use that analog cam in place of one of the failed cams. The other one still works in its original port. There was another analog cam (on siamese cable) that stopped, but came back when I switched it to an unused BNC port.

The XVR is a Dahua X58A5S4, purchased early 2022.

 

[bigredfish]

That’s not very old. Be interesting to know what’s causing the problem. I’m not a pro installer but I’m gonna say 90% of the time I had issues with an XVR/HCVR cameras it was the external camera power supply

 

[MC1987]

Two possible issues, new XVR's will have 2 BNC inputs on an AD chip. The two inputs must have the same format camera on them or you will see invalid camera format on the live view. Or it could be the video signal from the camera is not 1V ptp and recorder will not detect poor signalling from the video.

 

[paul@austins.tv]

Not sure what your suggesting, sorry.

New XVR's that I have and install. Have multiple BNC inputs depending on channel capabilities. You can convert to IP from the last remaining BNC connection. So on a 8 channel unit for example, you can have analogue 1-7 BNC and channel 8 IP and so on.
So BNC on channel 7, IP on 8, does work.

 

[bigredfish]

Yep, I ran 8 BNC+4 IP on my last XVR

 

[paul@austins.tv]

Yea indeed. On a 8 ch XVR, (unit dependant). You can have 8 BNC and another 8 IP (within bandwidth limit).
Not sure about the 2 BNC inputs have to have the same input as the previous poster suggested? They obviously have to be analogue CVI/TVI, etc.

 

[bigredfish]

I actually had, well still have but not in service, a 16 BNC channel XVR.

The two things that finally forced me to switch to an NVR and all IP cams were
1- No separate Day/Night profile for exposure etc on analog channels
2- Loss of IVS capabilities on the analog cams when i connected IP cams

 

[paul@austins.tv]

Yes indeed again. I currently have a XVR 7208 I2 just doing SMD and NVR 5216 4KS2 E, doing IVS. Both running fine.
Very much agree the hybrid XVR's have disappointing limitations.

 

[imnozi]

That’s not very old. Be interesting to know what’s causing the problem. I’m not a pro installer but I’m gonna say 90% of the time I had issues with an XVR/HCVR cameras it was the external camera power supply

Agreed. In this case, the external P/S seems to be OK, measuring 12.6 VDC on all connections at the box. And the couple I checked at the cams were still at/above 12VDC. Of course, that means little with no load. ... Oh, I have a sack of 12V fans; a 2W fan might show me if the cam P/S is failing to provide enough current.

But I still suspect the P/S inside the Dahua.

Basically, y'all haven't encountered young XVRs that are failing to display analog cams yet display the IP cams well. I'll have to go back down (hour drive) and open it up, see if there's an obvious problem, like dust buildup.

Thanks!

 

[bigredfish]

Not unless I've exceeded the output capacity or bandwidth of the XVR, no.

 

[imnozi]

Not unless I've exceeded the output capacity or bandwidth of the XVR, no.

And given that the cameras are all at 7FPS, I don't think I'm anywhere near the B/W limit.

 

[bigredfish]

Well you still have to consider the IP cams, bitrate … I think it all totals up

 

[bigredfish]

Sure all the actual connections out at the camera are OK? Balun wires etc, corrosion...

On IP NVRs the PoE ports (the models that have them) seem to come in banks of 4. So with a 16ch NVR, there are 4 banks of ports. Ive seen those go out due to a surge, usually the whole bank, so I'd lose 4 ports. Not sure how the NVR BNC ports are configured..

 

[imnozi]

True, they all have limited B/W. But the cams were all working for almost a year.

XVR only has two (or three) network ports. IP cams are connected to an external 24-port PoE switch. And both are connected to a UPS.