CRT:Frequently Asked Questions (FAQ)

Frequently Asked Questions (FAQ)

What is a CRT?

A Cathode Ray Tube display, characterised by its large vacuum tube. At the back is an electron gun which fires towards phosphors in the front, lighting them in a variety of colours. The gun re-angles while painting each image line by line, and the phospors fade before being redrawn anew.

The number of complete display updates completed per second is measured in hertz ("cycles"). 50hz or 60hz are common refresh rates for older televisions, although some sets can be made to update much faster. Use of a light gun accessory often requires a CRT: such devices, contrary to their names, actually contain cameras which track the progress of a CRT's refresh. By timing how long it takes for an electron gun to reach the region of the screen where they're pointed at, they can determine where that region actually is and hence what a player is shooting at. Flat panel displays (which remain fully lit at all times) are incompatible with this technique, forcing console developers to come up with other techniques - for eg, the Nintendo Wii appeared as CRTs started to fall out of fashion, and so included its own light sensor bar (a simple row of five infrared LEDs, tracked by a camera in the Wiimote hand controller).

CRTs don't have "pixels" as such: altering the number of rows they can display is a simple matter of controlling the angle the electron gun fires along. If too many rows are specified, the gun may not be able to move fast enough to maintain the target refresh rate, creating a flickering effect: interlacing is commonly used to alleviate this problem.

Most sets include either a dial or menu function for the purpose of recalibration, allowing any given image to be stretched / reduced to fit correctly. This is in contrast to flat panel displays, which have a specific number of pixels built into them which cannot be physically resized. Failure to use anything other than a flat panel's "native" resolution may result in colour dots being spread unevenly across multiple pixels, producing unnatural shapes. This is especially an issue when dealing with older consoles that tend to output lower display resolutions.

Where are all the nice CRTs?

Joebot's garage.

What is the default password for a Sony BVM's menus?

Try 1111, 9999, and 53415 ("SEALS"). Beyond that, start with guessing common sequences like 1234 or 9876 and other repeated digits like 2222 that someone may have set it to.

How can I check the hours on my monitor?

For Sony monitors, only Sony BVM and HDMs track hours. You can view the hours by going to Menu > Status. Some monitors will only list "Operation Time" — which is the time that the monitor has been on or in standby mode — and some monitors will also list "CRT Turn On Time" which is solely the amount of hours that an image has been on the tube (not in standby mode). Older BVMs will display their operation time count under the "Monitor Type" menu as an unlabelled number beneath the version number.

What is Y(B-Y)(R-Y)?

Y(B-Y)(R-Y) is YPbPr. Earlier monitors use the (B-Y)(R-Y) notation instead of PbPr.

Which consoles can output RGB / Component?

See the Console Video Output page.

How can I adapt my cables to (or from) SCART / BNC / RCA?

See the Connectors and Interfaces page.

Which CRTs can be modified to accept RGB?

See the RGB Modification page.

What's the difference between RGB / RGBS / RGBHV / RGBcvS / SoG / YPbPr?

See the Connectors and Interfaces page.

What is the difference between different Professional / Broadcast video monitors?

See the definitions of PVM and BVM at the bottom of this page and See the models list for specifics.

Where can I get my CRT serviced?

See the list of CRT Service Technicians.

How can I learn more technical information about CRTs?

See this guide which covers almost anything you could ask about CRTs.

What are some good video switchers?

SCART

• Hydra Switch (8 input / 1 output)
• gscartsw (8 input / 2 outputs)
• Otaku Switch (6 input)
• Shinybow SB-5525 (6 input / 2 outputs)

RCA / BNC

• Extron Crosspoint
  • 84 Series: 8 input x 4 output matrix
  • 88 Series: 8 input x 8 output matrix
  • 124 Series: 12 input x 4 output matrix
  • 128 Series: 12 input x 8 output matrix
  • 168 Series: 16 input x 8 output matrix
  • 1616 Series: 16 input x 16 output matrix
  • 2412 Series: 24 input x 12 output matrix
  • 2424 Series: 24 input x 24 output matrix
  • 3216 Series: 32 input x 16 output matrix
  • 3232 Series: 32 input x 32 output matrix
    • HVA models indicate audio support via Pheonix connectors
    • ADSP models regenerate a new sync signal on H/V
    • Takes both TTL and non-TTL sync input, only outputs TTL sync
• Otaku Switch (6 input)

Definitions

Term	Definition
TV Lines (TVL)	The maximum number of alternating light and dark vertical lines that can be resolved per picture height. Limiting factors include the driving circuitry, the number of phosphors on the tube, and the number of slots in the slot mask or aperture grille.
Flyback	(need a good definition)
Deflection	(need a good definition)
Pots	Potentiometers are components that can be adjusted to affect things like deflection, color balance, and voltage levels. Twistable knobs are just potentiometers that are accessible.
Convergence	Proper convergence means that the red, green, and blue spots generated by the three color CRTs inside your set are hitting the same point and therefore are creating the proper color.
Input Board	Input boards, or input cards, are modular cards that can be added or removed from professional CRTs. With Sony CRTs, only BVMs have input boards.
CVM	Color Video Monitor. Sony's original branding for PVMs from the early 1980s with composite and RF only.
PVM	Professional Video Monitor. Sometimes used generically to mean any professional monitor, but usually used to refer to Sony models starting with "PVM-". Originally used for professional image and video editing. They do not have removable input boards. Comes as a standard light gray color or a white color for medical variants. A very small amount of presentation PVMs (such as a PVM-2030) come in a beige color.
BVM	Broadcast Video Monitor. Sony models starting with "BVM-". Originally used for monitoring the master signal at broadcast studios when live on air to ensure perfect quality. These sets generally use the same tubes as equivalent PVMs, but have removeable input boards. All units come in light gray.
Phosphors	The patches of chemicals on the inside of the glass that lights up when the electron gun beam hits it. There are different phosphor formulations that fit standards such as SMPTE-C, EBU, P22, and EIA. They play a part in color accuracy and some phosphors output light for a longer period of time than others leading to a trailing or ghosting effect when a bright object is moved across a dark area, such as a cursor across a black background.
Pincushion	(needs a definition)
SSM	Security and Surveillance Monitor (?). Sony's line of monitors aimed to be used for security cameras. Generally the same internals as PVMs but with a dark gray shell.
VTR	Video Tape Recorder. Many sets have a VTR port on the back which can carry audio and composite video.
ISR	Interactive Status Reporting. A Sony proprietary system in which you can get diagnostic information from your Sony devices using a serial cable and the BZI-500 (or BZI-501) software on a Windows 95 / NT4 based PC.
RGsB	Sync on Green (SoG). RGB using 3 wires: Red, Green + Sync, and Blue.
RGBS (Composite Sync)	RGB with Composite Sync (CSYNC). RGB using 4 wires: Red, Green, Blue, and Sync (horizontal and vertical sync combined).
RGBS (Sync on Luma)	RGB with Luma as the sync signal.
RGBcvS*	CSYNC over composite video (composite video Sync). Also known as “sync on composite”. RGB using 4 wires: Red, Green, Blue, and Composite Video.
RGBHV	Independent sync. RGB using 5 wires: Red, Green, Blue, Horizontal Sync, and Vertical Sync. This is generally what PCs output on VGA ports.