1977/78 RCA TK-760 plumbicon colour broadcast studio camera
This is a RCA TK-760 three plumbicon tube colour broadcast grade studio television camera made around 1977/78. This camera was used possibly by HSV-7 from around 1977 to I guess the early/mid 1980s. This camera is actually a RCA TK-76 but mounted in a studio camera type enclosure for studio use, hence the 0 added to TK-76 to mark it's studio enclosure variation. This camera is the second broadcast camera to enter my collection and I am very proud to be the new owner of it and I endeavor to get this camera running good!!! The beauty about this camera is it's self-contained and does not need a CCU and PSU to operate it, you simply plug a mains cord into the mains socket on the camera, plug a BNC video lead into the video out socket and hook it up to a TV or monitor and power it up and there you have it, instant colour pictures!!! The camera can also be connected to a CCU as well as it has a multi pin socket for external control. This camera is generally a lower end of the budget type studio camera compared to the bigger studio cameras with CCU and PSU along with all the bells and whistles and was used more so by smaller TV stations who were running on a lower budget but also by main networks perhaps for lower budget programs. This camera has its basic controls on the back for adustment/alignment/testing such as contrast comparator, colour bars, high sensitivity, auto iris, tally call, white balance, -G (for tube alignment on a test pattern), G (green tube), R (red tube), B (blue tube), ext (external control I believe) and M (not sure what M does). The lens on this camera is of similar type to your standard lenses on 1980s portable VHS cameras with the zoom in/out buttons but also manual zoom as well, aperture adjustment, focus adjustment with also the auto focus switch. The lens can also be replaced with a studio type lens as well which is electronically adjusted. On the video outputs there is a monochrome output and a colour output and the multipin socket for external control by a CCU. This camera is pretty much very versatile as because of these options and plus you can even take the guts of this camera out and mount it back into it's portable TK-76 enclosure for portable usage.
Now onto the practical side of things. Since this camera is self contained, I decided to hook it up and fire it up and see if it works or not and on power up it is making pictures!!! :D This alone is excellent news, however there is problems with the pictures so it's not working correctly. Firstly it appears the is no output from the blue tube as I'm only getting a composite of red and green. Secondly there is an intermittent fault where the luminance will invert making the red/green composite picture go to a psychedelic glowy picture which looks really cool as a video effect but undesirable for the camera for its intended use. According to one of my friends these problems might only be just loose connections inside so the next step is to open the camera up and check the connections.
In the meantime here's a video demo of my TK-760 in operation followed by a series of photos:
Initial power up from the monochrome output gave somewhat unusual bars on without stepped greyscale, this was because I had one of the primary colour buttons pressed
A decent picture from the monochrome output of the camera :)
Colour bar pattern outputting perfectly from the camera :)
We have picture problems, seems that there's no output from the blue tube so there's only a colour composite of red and green primaries
Then comes this fault where the picture goes to a psychedelic glowing red/green picture, I believe the luminance has inverted itself as the white on the colour bar pattern goes black and the yellow goes dark
The picture on the viewfinder goes to a dark grey emboss which is unrecognizable
Wow that was quick, I'm already making excellent progress with this camera!!! I have decided to open the camera up and investigate for loose connections as suggested and indeed it turns out there is two loose connections. One on the lead coming from the blue plumbicon tube as suspected, the plug is loosely plugging into the socket but holding in good enough for the blue tube to output a signal when in properly. The other loose connection causing the luminance to go negative is still elusive but I have narrowed it to somewhere in the plumbicon tube bay area, will eventually locate it. Anyways the blue tube works and when the luminance is in normal positive, I am getting a half decent colour picture which is excellent!!! :D Of course to get a really good picture adjustments to the tubes are needed for optimum performance. Currently the picture is not bad but could be better, the colours are all there but a little desaturated and the picture is tinted blue so will have to adjust the tubes sometime when I get a hold of a TK-760 service manual which has the step by step procedures. Another thing I found is there was a couple of wires appeared to be cut, I believe they connect to the lens unit as the lens is not electrically functioning so I have to manually adjust the lens.
Anyways I am extremely happy this camera on the overall is electronically functioning very well and making full RGB colour pictures now!!! :D
Here below are 4 videos of the TK-760 in operation and myself talking about the internals of the camera. Part 2 I show the camera making a full RGB negative luminance picture and the loose blue tube lead and then I show and describe the camera's internal circuitry and adjustment controls from the left side. Part 3 I show and describe the camera's internal circuitry and adjustment controls from the right side. Part 4 I have the camera running good making a proper half decent colour picture and I get in front of the lens for kicks :). Part 5 I put a colourful video cover that has the full colour gamut in front of the lens to test the colour performance and also I discover the area where the loose connection causing the luminance to go negative is located.
And following the videos are more images of the camera which includes the circuitry of the camera and a couple of TV screen shots of the camera in operation.
More to come soon.
Service manual for this camera, if anyone has a service manual they are willing to sell me or scan/photocopy for me, email me at email@example.com
Video demo of my RCA TK-760 in operation (Part 2)
Video demo of my RCA TK-760 in operation (Part 3)
Video demo of my RCA TK-760 in operation (Part 4)
Video demo of my RCA TK-760 in operation (Part 5)
Left panel removed exposing the camera's circuitry, the circuit boards are strategically slotted into two main bus boards like peripheral cards slotted into the motherboard of a computer, I think this is an excellent set up because you can pull each circuit board out individually when servicing this camera which makes it so much easier for camera engineers to work on!
The bottom two circuit boards plugged into a smaller bus board. One circuit for the chroma and the other for the monitor
A closer view of the circuit boards slotted into the big bus board. From left to right: Camera tube drive, Auto B, Output Proc E, Delay 2 (625), Luminance 2, Chroma 2 PAL, Sync Pulse, Genlock Reference and Power supply
Power and output panel. On this panel is the switch for local or remote control for this camera, the mains input, a utility power output, a multi pin socket which I believe is to connect this camera to a CCU for external remote control, and below is a VF out which gives a monochrome picture and colour output for a colour picture which I've connected a BNC-RCA adaptor to
The control/adustment buttons at the back panel of the camera which includes: contrast compare (this I believe autoadjusts contrast), colour bar pattern, high sensitivity (guess this auto sets the sensitivity of the picture), automatic iris (automatically focuses the lens), tally call (signals the tally light at the top), white balance (corrects the white balance so whites are whites and not any other colour tint), -G (I am sure this is used for tube convergence alignment from memory), G (green tube), R (red tube), B (blue tube), EXT (think it might have something to do with external CCU control), M (don't know what this button does)
The plumbicon tube bay where the 3 tubes for each primary colour are strategically positioned in front of an optical beam splitter prism
Some control switches below the plumbicon tube bay
Plumbicon tube driver board
Camera displaying a full RGB composite colour picture but with negative luminance
Inside the camera from the right side, here the 2 main bus boards can be seen which hold all of the slotted circuit boards on the left side, also theres an adjustment panel for the 3 plumbicon tubes and below it the mains power panel with adjusments
A distant shot showing the whole camera with the right panel removed
Mains power board with power adjustment pots
The smaller bus board at the bottom for the two circuit boards below on the left side
The main bus board for most of the circuit boards on the left side
Adjustment panel for the three plumbicon tubes, this is where the engineers spend considerable time adjusting the tubes for optimum colour pictures
An interconnection plug
Camera displaying a half decent colour picture while in proper working order
A direct video output from this camera to show the how the images look, due to recording to VHS tape the pictures look inferior to how they look directly from camera output to TV. Also this was done in the evening so I had to use two flood lamps I bought from Woolworths to get a decent image. I will soon make another video directly to DVD recorder for a better picture and done in daylight which the lighting will obviously be much better and this camera will make even better pictures!
This is my second video I have made directly from the video output of the TK-760. It seems the pictures look more out of alignment in this video shot mid afternoon than in the one that was shot in the evening with a couple of flood lamps. I couldn't quite get the colour tones right nor the white balance so the images look of a blue/green tint, plus it appears the convergence is way off this time. So a lot of alignment is needed, plus the tubes may have to be replaced too as I'm getting green blotches in the picture too. Anyways this is 21 minutes of TK-760 footage, I goof around in front of the camera a few times and I film stuff in the front yard and in the garage, enjoy! :D
Video demo of my RCA TK-760 in operation (Part 6)
Here below are some pics of the TK-760 in operation during the filming