JVC Newvicon Camera Connections

[EdKozk2]

Hello,
I bought a JVC GX-N70U Newvicon camera, at Goodwill. It came with its viewfinder. I opened it up to trace the 12VDC power connections. The camera viewfinder has a raster. The title maker keboard also works.
The camera pickup tube does not televise in the viewfinder when I switch to camera mode. Does this camera have special connections to activate the newvicon tube ? The camera uses a 12 pins in the connector. The bottom two are for 12vdc. I would like to get the video signal out working if possible.
Any help would be great.

Thanks,
Ed

[Boobtubeman]

You should be seeing an image in the vuewfinder. I havent had to do any special connections at the plug to get a picture in the vuewfinder.

Check all settings around the lens, see if aiming lens at a lightsource is visible in the vuefinder

SR

[Dave A]

Those vintage cameras had a lot of tricks built in. The one I am thinking of is "fade in/fade out". Yours could be stuck in "fade out" which would close the iris and age may have the lens stuck closed.

There is not a lot of signaling in the connector. 12v, video out, video in from a VTR for playback and the audio channels. Nothing discrete after that. Simple analog.

You did not say what you are using for 12v. It may not have enough amps for proper operation. That is a tube and it needs power and the lens is looking for some also for the motors. Look for vintage portable VCR/tuners that it would direct connect to. The tuner has the amps delivered to the VCR and to the camera (and forget using the VCR batteries...they are all dead and gone) or camera power supplies of the vintage with the connector and outputs on the side for connecting to a standard VCR.

Even my RCA tube camera with the Indextron VF did not work properly on a RCA CC-002 camera power supply. It needed a VCR to operate.

[Boobtubeman]

Some cameras had a manual white balance that would block the lens as well...

SR

[EdKozk2]

Thanks, for the info Boobtube man and Dave A,
I got the viewfinder to display the televised object. Operator error on my part. Not the best focus. When I activate the titling option I get a horizontal tear in the view finder. Reminds me of improper sync/overload. I'm using a 1 amp RS transformer, the camera name plate calls for 600ma. Now I can check the video out on a monitor, to see what else may be wrong.
Ed

[EdKozk2]

Tonight I powered up the newvicon camera and traced the video signal out. I connected the video to a television. To my surprise the picture was better quality than I expected. The horizontal/sync tear I saw in the viewfinder didn't show up on
the monitor. Now that I know the camera works, I need to find a female 13 pin connector/cable. The camera's view finder connector is the same as the power/vcr connector.

[EdKozk2]

Does anyone have the service data/schematic for the JVC gx-n70u camera? I found a guy on the net, but he won't be able to send them for over six months.
The camera has tint control issues, the tint control doesn't even work. Orange colored objects look more brown to maroon.
Does any one know how colors are separated in a single tube pickup camera?
Ed

[ChrisW6ATV]

The basics of getting color from a single tube is that there is a color-striped-grid overlay (sticker) on the face of the tube, and circuits that matrix everything into color. Exactly how it works, I was not clear on when I read one of the service manuals, and that was a number of years ago.

[EdKozk2]

I could see a slight amount of light green tinting when viewing outside scenes. I read somewhere aging Newvicons are prone to this greening.

[wiseguy]

try this
Leave it on for about 5 mins or so, lens capped
after warmup remove lens cap, set zoom on wide, but do not aim at any bright light but just something in the room, looks for a control on Deflection or HV board called "BEAM, or Beam Current" turn very slowly clockwise till you start to see more of an image appear, and stop to where image stops Flare green in highlight areas.
also if tube Focus has been messed with the image will always look green, so don't touch that control as these sort of interact with each other.
Tube focus (not lens focus) is adjusted for best focus at start of center of image and when "minimal Green Carrier" is gone, but the perimeter of the image is touchy to align, this is where the Horiz, Vert sawtooth parabola adjustments take care of that.
but I would only adjust Beam and hopefully no one has messed with any of the other controls

[old_tv_nut]

Originally Posted by ChrisW6ATV

The basics of getting color from a single tube is that there is a color-striped-grid overlay (sticker) on the face of the tube, and circuits that matrix everything into color. Exactly how it works, I was not clear on when I read one of the service manuals, and that was a number of years ago.

The most common color stripe pattern was diagonal stripes of cyan going one way and yellow going the other. I'm guessing that's what this camera used.
This produced a mixed high frequency subcarrier of red modulation and blue modulation that could be separated by a comb filter. Doing this successfully depends on having good electron beam focus and also depends on having the correct scan height so the high frequency red and blue signals are out of phase on alternating lines. If the electrical focus is bad, the amount of red and blue is reduced, and the picture turns greenish.

Another possible method was to have two different frequencies (line spacings) for the yellow and cyan. Another possible arrangement is separate electrode patterns for red, green, and blue (some Sony's, I think).

[EdKozk2]

Wiseguy,
Are you saying an increase in beam current will reduce green flare in highlighted areas? Does this increase in beam current reduce the life of the newvicon tube?
I did notice this green flare when I aimed the camera toward the treetops and far away. The camera was set on wide angle. The sky was very overcast. The focus seemed OK aslo.
I'll have to try this adjustment this weekend.
Thanks,
Ed

[EdKozk2]

Old tv nut,gs
Sounds like aging caps and resistors could through the factory settings way off?
Ed

[Dave A]

The tube will show some beam flare as you move from the darker trees to the sky but it should bleed off quickly as the auto iris kicks in for the brighter sky. If it is slow or does not bleed off then a touch-up is needed. The tube is getting old.

[EdKozk2]

Originally Posted by Dave A

The tube will show some beam flare as you move from the darker trees to the sky but it should bleed off quickly as the auto iris kicks in for the brighter sky. If it is slow or does not bleed off then a touch-up is needed. The tube is getting old.

Thanks Dave.