A flare for these things

[nikko]

Greetings everyone.

I've a PTZ with a new JVC camera & computar 8-120mm zoom lens inside. When the cam follows something bright, like a shiny vehicle, a little noise appears on the picture. I've activated BLC & this worked for 24 hours! Oh by the way it's on fiber.

P-P is 1.18v & Sync is 2.8v.

Any ideas are gratefully received.

[Rich]

Can you be more specific about the noise on the picture, is it grainy?

Model of camera too please.

[Rich]

Also is it at day or night and what shutter speeds are you using. Is the camera moving when the noise appears or does it happen when stationary.

[ian.cant]

Bright light is the problem as bright white is at the 1v end of the scale. Your noise will be be because of the high signal/voltage at peak which if you put it on a scope when you have too much bright white your gonna be way over 1v peak.

This is difficult to diagnose for sure without seeing the picture and even harder to cure.

[Rich]

Any chance of getting a picture of the problem?

With the model of camera we would have an idea of what can be done with it to try and help matters.

I agree its probably too high level, but I would like to rule out things like poor gnd connections on the lens and AI connections.

Wonder if nikko will ever reply, and what you still doing up at this time Ian, does it get darker later up there ?

[nikko]

Hi guys

Sorry for the delay in replying. I've just had 3 town centres dumped on me & with the existing kit been quite worn, the faults are keeping me very busy!

I've not noted the camera model yet, it's the one with cursor controls on the back, 230volts and colour. Any help?

The picture is a slight flicker but not grainy, most noticable when the PT is in the down position. I've ruled out a strained coax.

Interestingly, following further investigation, the p-p from the matrix is at 1.26volts. This finally goes through a Panachronic VCR to a spot monitor. The VCR pushes the p-p up to 1.5volts. If I bypass the VCR the problem goes away, however a colleague had the same problem & swapped the VCR a few weeks ago, so I'm not convinced it's the VCR.

I've also tried changing in/out from the matrix.

I'll stick the scope on it on Monday when I've got round the other million faults!

Peace & love guys

[Guest cctvman]

Jvc mains camera, cant remember the model number (1216 or there abouts) but one of the fav faults is the psu going in the older ones or the filtering going in the psu noisy output voltage,

Check the signal @ the camera end first mate after the telemetry as i suspect it going to be one of the following

1 the camera

2 the t/l board output if coax t/l (check to see if signal o/p is turned way up)

3 lens faulty or set too high & camera chip/amp cant handle it

4 power supply (once again internal psu )

Least you can rule out the camera end if nothing else

Regards

Al

[Guest cctvman]

Oh forgot,

I hope your not using BLC on an external camera ?????

Cctvman

[ian.cant]

Oh by the way it's on fiber.

BTW in my experience, fiber usually has a method of tweaking the gain, usually at the reciever end, that would help to drop the high signal input, maybe!

[nikko]

guys.

I stuck the scope on the other day & everything was sitting pretty, sync@ground to 0.3, 1v p-p, chromaburst where it should be. I think I'll try swapping the camera when I get chance & I'll let you know of any success.

Thanks for replying all

xx

nikko's website