More Lens help needed

[cachecreekcctv 0]

I hope this is simple for someone out there. I recently purchased a Computar Motorized lens , but with Auto Iris. The motorized connections are easy to figure out and deal with, but not so on the AI function. I guess I have never actually wired up the AI pin, as every lens I have ever purchased before, came pre-wired, as I guess 99% are. Anyway, I was hoping someone could help me figure out the wiring part. The lens will go on a Sony SSC-DC393 Color Cam. The lens actually, was used, so I got a great deal. I tested the zoom, and focus motors, both work perfect, just need help in the AI wiring. I know my camera is functioning OK, as I can take another AI lens, and both work OK. Only 4 wires, but cannot get any combination to work. Thanks for all the help/suggestions!!

[kensplace 0]

what is the model number of the lens?

[cachecreekcctv 0]

The lens is a Computar model # T6Z5710AMS-CS. It still has the tag on both the motorized part, and on the AI cord. Never tried it, but the paperwork shows 9VDC going to AI. Could I use a 9v battery to open up iris???? Lens was hardly used, kept in housing all the time. I have wiring diagram in box, so that is not the problem. I actually never saw lens in action, so other than the two motors, I can't honestly state that the AI function works. I have another Computar lens, similiar to this, but with motorized iris, and it works on same camera. Just one less motor to deal with, on AI lens I guess.

[kensplace 0]

Wire up the power (red and black wires) to the corresponding ones on the cameras iris socket, connect the white wire to the video signal on the iris socket, you should be able to ignore the green wire.

 

The green is for 'level remote' and is used to overide the iris circuitry in the lens itself, usually the lens will read the video signal from the camera and adjust the iris to suit, but the level remote allows you to remotely overide this.

For auto use, just ignore level remote.

 

Your camera will also be switchable between video or DC iris control, make sure thats not the problem, it may be set wrong.

 

Should work, unless there is a problem with the iris, or its wired incorrectly.

 

(ps the iris does not have a motor, its galvanometer controlled, basically a little spring like coil moved by current)

[cachecreekcctv 0]

Thanks, did all that already. Thought there might be something I missed on the lens. Could be the AI part of the lens is bad?? Any other suggestions?

[kensplace 0]

After double and triple checking all wiring/connections/settings on cam then if still no joy then probably its either the cam or lens that has a problem, I think you said another ai lens works on that cam so it could be the lens.

 

On non zoom lenses (not taken apart any zooms yet, not had to luckily) that were AI I have fixed a couple that suffered from broken wires inside where the connections had came of the board. Another had a broken potentiometer, I ended up just wiring a big one on the outside as I had non that fitted (hey it worked )

 

Also check non on the wires are snapped, a continuity check between the end and the connection inside on the board with a multimeter can rule that out.

 

 

Once one end of the galvanometer spring thing had came of its mount so it had no tension, I (JUST) managed to get it back on, and it worked ok, but it was touch and go. Another one with the same fault I bust totally, and ended up forcing the iris open fully with a bit of paper and letting the electronic iris in the camera do the job instead.

 

Dismantling lenses is not for the faint hearted, or those with less than perfect eyesight/lighting and patience.

[cachecreekcctv 0]

Thanks. So there is a way to "bypass" the AI function on this lens, and allow the camera itself to take over the iris function? I might have to do that. When you did that particular operation, how did it turn out? Viewing OK?

[kensplace 0]

The lens is normally controlled by the camera, although its a AI lens, and will have circuitry, at the end of the day, all that does is amplify the video signal enough to open/close the iris depending on how bright the scene is.

 

There is the remote wire, but that is not controlled by the camera, thats normally controlled by a controller that has preset settings for iris/focus/pan/tilt positions. You can try wiring that up to see if it does anything, if you look at the wiring schematic you will see its easy enough to use a potentiometer to vary the voltage on the wire as they do in the example.

 

Chances are if the iris is stuck, its stuck, but guess it could be worth a try, although you would have zero auto controll, but the electronic iris on the camera can usually cope if you managed to get the iris open enough.