Posted on 10 Comments

Sony HVC-3000P Trinicon Camera Teardown

Camera Left
Camera Left

Following on from the viewfinder teardown, here’s the rest of the camera. This unit dates back to 1980, and is made almost exclusively of cast aluminium. Very little plastic has been used here & only for the bits that the user comes into contact with. This camera is based around the Sony Trinicon camera tube system, technology dating back before CCDs. There aren’t many controls on this side of the camera, only the record button, which is hidden behind the camera handgrip.

Camera Right
Camera Right

The other side of the camera has most of the controls for the picture.

Image Controls
Image Controls

The image controls inclue auto / manual iris, white balance & colour balance.

Rear Panel
Rear Panel

Sharpness & fader controls are on the back of the camera, along with the umbilical cable which would have connected to a Betamax recorder.

Main Lens
Main Lens

The lens on this camera is massive, at least a kilo of optical glass. Focus control is manual, with both auto & manual zoom control.

Lens Zoom Control
Lens Zoom Control

The Zoom controls are on top of the grip, with a button to the rear of the control which I have no idea about. The internal belts are a bit rotted with age so the zoom function doesn’t work great.

Trinicon Control Board
Trinicon Control Board

After removing the side covers, the two large PCBs become visible. These units are absolutely packed with electronics. On this side is the Trinicon tube control board, generating all the high voltages for electron beam acceleration, focus & electrostatic deflection of the beam. There’s around 500 volts knocking around on this board, with some rather specialised hybrid modules doing all the high voltage magic.

Video Process Board
Video Process Board

The other side of the camera has the video process board, which performs all the colour separation of the video signal from the tube, processes the resulting signals into a composite video signal, and finally sends it down the umbilical.

Bare Controls
Bare Controls

Removing some of the remaining covers exposes the bare video controls, and a small PCB just underneath covered in trimpots to set factory levels.

White Balance Filter Arm
White Balance Filter Arm

The white balance is partially electronic & partially mechanical. This lever actuates a filter inside the lens assrembly.

Remote Connector
Remote Connector

A DIN connector offers remote control ability. The large loom of wires disappearing off to the right is dealing with the zoom mechanism & the onboard microphone amplifier. Just under the DIN connector hides the system power supply, inside a soldered can. The can under the white tape is the head end amplifier for the Trinicon video tube.

Trinicon Mount
Trinicon Mount

Hiding in the centre of the camera inside the casting is the Trinicon tube assembly itself. The label can just be seen here.

Camera Internals 1
Camera Internals 1

As is typical of 1980’s electronic design, the main boards swing down & are designed to slot into the base casting folded out for repairs. Internally the unit is a rat’s nest of wiring loom. There’s also another shielding can in here nestled between the boards – this is the video sync generator circuit.

Camera Internals 2
Camera Internals 2

The other side gives a better view of the video sync generator can. I’ll dive into the individual modules later on.

Lens Zoom Assembly
Lens Zoom Assembly

Under the remaining side cover is the zoom assembly & microphone amplifier board. More massive wiring loom hides within.

Video Sync Generator
Video Sync Generator

The video sync generator is pretty sparse inside, just a large Sony CX773 Sync Generator IC, with a pair of crystals. There are a couple of adjustments in here for video sync frequencies.

Head End Amplifier
Head End Amplifier

Removed from it’s shielding can, here is the head end amplifier for the Trinicon tube. This very sensitive JFET input amplifier feeds into the main video process board.

Input Transformer
Input Transformer

The Trinicon tube target connects to this input transformer on the front of the amplifier board.

Internal Video Adjustments
Internal Video Adjustments

The internal white balance controls are on this small PCB, mounted under the user-accessible controls.

Vidicon Control Board
Vidicon Control Board

Here’s the main control board responsible for the Trinicon tube & exposure control. Down near the front is the auto-iris circuit, nearer the centre is timing control & at the top is the high voltage power supply & deflection generator ICs.

High Voltage Section
High Voltage Section

Here’s the high voltage section, the main transformer at right generating the voltages required to drive the video tube. The large orange hybrids here are a pair of BX369 high-voltage sawtooth generators that create the deflection waveforms for the tube. The other large hybrid is a BX382 Fader Control.

Video Process Board
Video Process Board

The other large board contains all the video process circuitry, all analogue of course. There are a lot of manual adjustment pots on this board.

Lens Barrel
Lens Barrel

After removing the lens assembly, the tube assembly is visible inside the barrel casting. Not much to see yet, just the IR filter assembly.

Trinicon Tube Assembly
Trinicon Tube Assembly

Here’s the unit removed from the camera. Unfortunately this tube is dead – it shows a lot of target burn on the resulting image, and very bad ghosting on what poor image there is. The Trinicon tube itself is encased in the focus coil assembly, the windings of which are hidden under the shielding.

IR Filter
IR Filter

The IR filter is locked into the front of the tube, on a bayonet fitting. The twin target wires are running off to the left, where they would connect to the head end amplifier.

Bare Tube
Bare Tube

After removing the IR filter glass, the Trinicon tube itself is removed from the focus coil assembly. There’s an electron gun at the rear of the tube, like all CRTs, although this one works in reverse – sensing an image projected on the front instead of generating one.

Deflection Plates
Deflection Plates

It’s a little difficult to see, but the electrostatic deflection electrodes in this tube are created from the aluminium flashing on the inside of the glass, in a zig-zag pattern. The interleaving electrodes are connected to base pins by spring contacts at the electron gun end of the tube.

Electron Gun
Electron Gun

The electron gun is mostly hidden by the getter flash & the deflection electrodes, but the cathode can is visible through the glass, along with the spring contacts that make a connection to the deflection electrodes. This is also a very short gun – it doesn’t extend more than about 5mm into the deflection zone. The rest of the tube up to the target is empty space.

Target
Target

Finally, here’s the target end of the tube. I’m not sure how the wires are attached to the terminals – it certainly isn’t solder, maybe conductive adhesive?
It uses a vertically striped RGB colour filter over the faceplate of an otherwise standard Vidicon imaging tube to segment the scan into corresponding red, green and blue segments. It is used mostly in low-end consumer cameras, though Sony also used it in some moderate cost professional cameras in the 1980s.
Although the idea of using colour stripe filters over the target was not new, the Trinicon was the only tube to use the primary RGB colours. This necessitated an additional electrode buried in the target to detect where the scanning electron beam was relative to the stripe filter. Previous colour stripe systems had used colours where the colour circuitry was able to separate the colours purely from the relative amplitudes of the signals. As a result, the Trinicon featured a larger dynamic range of operation.

Posted on 2 Comments

Sony HVF-2000P Viewfinder Teardown & Composite Video Hack

Rating Plate
Rating Plate

Well, it’s time for another viewfinder hack! I’ve been after one of these for a while, this is from an early 1980’s era Sony Trinicon camera, and instead of the tiny ½” round CRT display, these have a 1.5″ square CRT – a Matsushita 40CB4. Luckily I managed to score a pair of these from eBay for very little money. Update: The second camera’s viewfinder module turned out to have a dead flyback transformer, but at least I have a good spare CRT & the rest of the support components. More to come later on the teardown of the camera itself.

Mirror & Eyecup Assembly
Mirror & Eyecup Assembly

The eyecup assembly with the magnifying lens & turning mirror is easy to remove, with clips & a single screw holding it onto the CRT holder sticking out of the side of the main casing.

Top Cover Removed
Top Cover Removed

Removing some screws around the case allows the top cover to be removed, revealing the electronics. There’s certainly more in here than the later camera viewfinders, in this unit there are two boards slotted together with a board-to-board interconnect at the bottom. The CRT is at the top of the photo, hiding inside the plastic housing & deflection yoke assembly.

Bare PCBs & CRT
Bare PCBs & CRT

Here’s the CRT & one of the control boards removed from the case, having been stripped of the heatshrink tube that held the final anode lead in place. Just like on larger CRTs, this viewfinder has the final anode on a cavity connector fused into the bell, instead of being led out to a pin on the base. This is probably due to the much higher anode voltage of 5kV, a big jump from the 2kV on the ½” round tubes.

40CB4 CRT Label
40CB4 CRT Label

Yup, it’s definitely the elusive 40CB4. Apparently these CRTs are still manufactured to this day for professional camera viewfinders, as the resolution of this small vacuum tube is still better than similarly sized modern tech such as LCDs or OLEDs. The phosphor used is type P4 – ZnS:Ag+(Zn,Cd)S:Ag, with an aluminized overcoat.

Bare 40CB4 CRT
Bare 40CB4 CRT

After the base connector & deflection yoke are removed from the tube, the very long neck can be seen, this long glass neck apparently giving better focus & resolution than the stubbier tubes.

Electron Gun
Electron Gun

The electron gun is the usual single unit as usually found in monochrome tubes.

Deflection Board
Deflection Board

The bottom board in the assembly has all the control circuitry for the CRT, including the HA11244 deflection IC, composite sync separator & vertical deflection drive circuit. There are also circuits here to display a video waveform on the CRT, along with iris & white balance markers.

Horizontal Board
Horizontal Board

The other board has the horizontal drive circuitry, along with the video input amplifier. Despite the attempt to miniaturize the entire assembly, these are still well packed boards. Some of the resistors & diodes are bussed together in custom SIL hybrid modules to save PCB space. Like all the other CRT viewfinders, these units are meant for viewing via a mirror – the horizontal deflection coil connections need to be reversed to show a correct image without the mirror. The Red & Blue wires to the yoke need to be swapped here.

Flyback Transformer
Flyback Transformer

The horizontal board on this unit also supports the flyback transformer, which is massive compared to the other viewfinder circuits. Biasing, focus & filament supplies for the CRT are also derived from this transformer, via auxiliary windings.

Boards Connected
Boards Connected

The boards slot together in the centre to form the fully operational circuit.

Video Input
Video Input

Out of the 3 plugs emerging from the cable feeding the viiewfinder, only this one is important, on the horizontal drive board. Black is ground, Brown +8.5v & red is composite video input. There’s also a resistor tied into the positive rail to the video input pin, which pulls it high to 8.5v – this is R1 right next to this connector. Desolder this 22K resistor to help protect anything feeding a signal into the unit, like a RPi, it’s not needed for normal operation.

Fallout!
Fallout!

As usual for a CRT post, the Fallout loading screen on the display. The picture quality isn’t as good as it should be, probably due to the noisy buck-converter I have rigged up for testing. If it doesn’t get better with a linear regulator, I’ll start replacing the 39 year old electrolytic capacitors. Current draw is 130mA at 7.5v. Schematics for this unit & the CRT datasheet are available below:



Posted on 2 Comments

Goodmans Quadro 902 Composite Video Mod

CRT Module
CRT Module

Here’s the CRT & it’s drive board removed from the main chassis. Nicely modular this unit, all the individual modules (radio, tape, TV), are separate. This is effectively a TV itself, all the tuner & IF section are onboard, unlike in other vintage units I’ve modified, where the tuner & IF has been on a separate board. There’s a 3-pin header bottom centre for the tuning potentiometer, and external antenna input jack. The internal coax for the built in antenna has been desoldered from the board here. here a the usual controls on the back for adjusting brightness, contrast & V Hold, all the other adjustments are trimmers on the PCB.
Unfortunately after 30+ years of storage, this didn’t work on first power up, neither of the oscillators for vertical or horizontal deflection would lock onto the incoming signal, but a couple of hours running seemed to improve things greatly. The numerous electrolytic capacitors in this unit were probably in need of some reforming after all this time, although out of all of them, only 21 are anything to do with the CRT itself.

Anode Cap
Anode Cap

Here’s the anode side of the unit, with the small flyback transformer. The rubber anode cap has become very hard with age, so I’ll replace this with a decent silicone one from another dead TV. The Horizontal Output Transistor (a 2SC2233 NPN type) & linearity coil are visible at the bottom right corner of the board. Unfortunately, the disgusting yellow glue has been used to secure some of the wiring & large electrolytics, this stuff tends to turn brown with age & become conductive, so it has to be removed. Doing this is a bit of a pain though. It’s still a little bit flexible in places, and rock hard in others. Soaking in acetone softens it up a little & makes it easier to detach from the components.

Neck PCB
Neck PCB

There’s little on the neck board apart from a few resistors, forming the limiting components for the video signal, and the focus divider of 1MΩ & 470KΩ feeding G3. No adjustable focus on this unit. There’s also a spark gap between the cathode line & ground, to limit the filament to cathode voltage. The flyback transformer is nestled into the heatsink used by the horizontal output transistor & a voltage regulator transistor.

Tube Details
Tube Details

The CRT is a Samsung Electron Devices 4ADC4, with a really wide deflection angle. It’s a fair bit shorter than the Chinese CRT I have which is just a little larger, with a neck tube very thin indeed for the overall tube size.
Unusually, while the filament voltage is derived from the flyback transformer as usual, it’s rectified into DC in this unit, passing through a 1Ω resistor before the filament connection. I measured 5.3v here. The glow from the filament is barely visible even in the dark.

Electron Gun 1
Electron Gun 1

The electron gun is the usual for a monochrome tube, with 7 pins on the seal end.

Electron Gun 2
Electron Gun 2

The electrodes here from left are Final Anode, G3 (Focus Grid), Accelerating Anode, G2 (Screen Grid), G1 (Control Grid). The cathode & filament are hidden inside G1. In operation there’s about 250v on G2, and about 80v on G3.

Chipset
Chipset

The chipset used here is all NEC, starting with a µPC1366C Video IF Processor, which receives the IF signal from the tuner module to the left. This IC outputs the standard composite signal, and a modulated sound signal.
This then splits off to a µPC1382C Sound IF Processor & Attenuator IC, which feeds the resulting sound through the two pin header at the right bottom edge of the board to the audio amplifier in the chassis.
The composite video signal is fed through a discrete video amplifier with a single 2SC2229 transistor before going to the CRT cathode.
The remaining IC is a µPC1379C Sync Signal Processor, containing the sync separator, this is generating the required waveforms to drive the CRT deflection systems from another tap off the composite video line.
From this chip I can assume the unit was built around 1986, since this is the only date code on any of the semiconductors. Besides these 3 ICs, the rest of the circuit is all discrete components, which are well-crammed into the small board space.
There are 5 trimmer potentiometers on the board here, I’ve managed to work out the functions of nearly all of them:

  • SVR1: IF Gain Adjust
  • SVR2: H. Hold
  • SVR3: V. Size
  • SVR4: B+ Voltage Adjust
  • SVR5: Tuner Frequency Alignment? It’s in series with the tuning potentiometer in the chassis.
PCB Bottom
PCB Bottom

The PCB bottom shows the curved track layout typical of a hand taped out board. The soldermask is starting to flake off in places due to age, and there a couple of bodge wires completing a few ground traces. Respinning a board in those days was an expensive deal! Surprisingly, after all this time I’ve found no significant drift in the fixed resistors, but the carbon track potentiometers are drifiting significantly – 10KΩ pots are measuring as low as 8KΩ out of circuit. These will have to be replaced with modern versions, since there are a couple in timing-sensitive places, like the vertical & horizontal oscillator circuits.

Anode Cap Replaced
Anode Cap Replaced

Here the anode cap has been replaced with a better silicone one from another TV. This should help keep the 6kV on the CRT from making an escape. This was an easy fix – pulling the contact fork out of the cap with it’s HT lead, desoldering the fork & refitting with the new cap in place.

Here I’ve replaced the important trimmers with new ones. Should help stabilize things a little.

Composite Injection Mod
Composite Injection Mod

Injecting a video signal is as easy as the other units. Pin 3 of the µPC1366C Video IF Processor is it’s output, so the track to Pin 3 is cut and a coax is soldered into place to feed in an external signal.

CRT In Operation
CRT In Operation

After hooking up a Raspberry Pi, we have display! Not bad after having stood idle for 30+ years.

Datasheets for the important ICs are available below:
[download id=”5690″]
[download id=”5693″]
[download id=”5696″]