I have just obtained 2 new cameras which are 12vDC/24vAC auto switchable, when turned on using a 12vDC supply, it can take some 5 minutes for it to warm up and get a stable picture.
I dont suppose this is normal, or is it?? there isnt a drop in voltage after turning on.
I dont want to go and buy an AC supply to find things are the same.

any ideas please

I can't say what's wrong but I can confirm that it shouldn't take 5 minutes to get a stable picture with that camera.

Yup, it should not take that long, what are you seeing on screen during the 5 minute warm up (out of curiousity) is it just snow, or black screen, or distorted picture?

Im sure I had one of those cams before (it may have been a 9712 though to think of it) and it developed a problem where it would not always power up, and sometimes died in use - the circuit boards inside were loose, they connect to each other with pins in sockets, and they needed to be reseated (and I ended up having to use a bit of card to jam in the side to make sure they did not work loose). Could be worth a check to make sure they are all nice and tight inside (powered down!)

1 1/2 mins black/white flickering
2 mins of black screen
1min inverse picture
2mins picture slowly appears until normal

some screen shots

What is the amps for the camera and what is the rating for the power supply?

the camera is rated 5W so <0.5 amp. I am using a 12VDC 4A supply. I have tried other supplys as well.

I had a thought after my last post (as the cam also accepts 12-30VAC).
(quick rummage through my xmas decorations lighting box, aha! a 24vac class 2 transformer.)
connect it up, turn on and all working within 10 secs.

So either the auto AC/DC switcher isnt working properly,
or
as the camera is rated 11 - 40 VDC needs more than 12v

cctvgear repair this model of camera. It is likely that the capacitors on the psu board have dried out and require replacement.
Regards
Sean@cctvgear.co.uk

many thanks sean, I will bear that in mind if I need to use it permenantly