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In the normal course of events the operation of most video monitors goes unnoticed, until they go wrong. Fortunately that’s a fairly rare occurrence these days, they’re one of the most hard-working, yet reliable components in a video surveillance system.  Part of the reason for that is their relative simplicity and the fact that they rely upon mostly tried and tested technologies. Indeed, the origins of the cathode ray tube display can be traced back more than 100 years. It also helps that a lot of video monitors are made by companies who also manufacture domestic televisions; in principle the two devices share a good deal of common circuitry and there is the opportunity for cross-fertilisation in design and manufacture, plus some useful economies of scale.


JVC are very well placed in all those respects and their long and honourable heritage with both living-room TVs and professional video monitors is clearly evident on the TM-1700PNK. This 17-inch PAL/NTSC colour model looks and feels like a refined piece of kit, the quality of construction is excellent. Every panel fits together neatly, it is housed inside a tough steel case, controls are accessible and logically laid out moreover the rear panel connections are grouped together and clearly labelled.  The same attention to detail continues on the inside. All of the power supply and display circuitry is contained on a single PCB in the bottom of the cabinet. A second daughter board, mounted on the left side of the chassis, is responsible for all for the video processing, on-screen display and audio functions. The main board slides out for easy servicing, cables and interconnections are neatly dressed and easy to get at.


High grade components are used throughout, and that includes the 44cm Philips picture tube which is an FST type with 90 degree deflection.  Phosphor stripe pitch is quoted at 0.42mm, which puts it between high-grade domestic TV tubes and computer monitors. The square cornered tube has enabled the designers to use a narrow screen surround; apart from the cosmetic benefits it maximises the picture area, without wasting a lot of space on a large or bulky cabinet.  


JVC have kept to a fairly routine specification, though there are a few useful extras including a menu-driven on-screen displays and push-button controls, instead of rotary knobs or switches. It has two video inputs, designated A and B; input A is composite video only, via a BNC connector. Input B has both composite and Y/C inputs, (BNC and 4-pin mini DIN), inputs are selected manually by buttons on the front panel. This arrangement actually means the monitor can handle three independent video inputs -- two composite and one Y/C -- JVC make no mention of it in the instructions, but we tried it and it works perfectly well.


The two video channels each have an associated bypass output socket, for connection to a VCR, plus line-level audio input/output sockets (RCA/phono). These are switched with the vision signal, and heard on an internal speaker, mounted on the right-side of the case (as seen from the front). The 8cm round speaker is driven by a 1 watt amplifier.



All of the controls are located on the front panel. They are grouped together according to function, apart from the main on/off switch, which is on it’s own, on the far right. Next to it are the three video input selector buttons, each has its own green LED indicator, to show which channel is in use. In the middle of the panel there’s another three buttons; the two largest ones are for setting the speaker volume -- by default -- and changing picture settings and menu selections, when the on-screen display is being used. The third button calls up the on-screen display main menu. The remaining four buttons on the left side of the panel are concerned with picture and menu functions. The first one selects phase adjustment mode, for altering picture hue, when the monitor is connected to an NTSC source. It also acts as a the down cursor control on the menu display. The second button selects colour saturation adjustment mode, and up cursor when the menu is on screen. Button  three selects brightness and the fourth button calls up the contrast setting. In all cases the picture settings are shown graphically, with a sliding indicator, and numerically, with a two-digit readout.


There are three menus. The first one covers the main display settings (sharpness, colour temperature, colour  system, aspect ratio and BPS or brightness peak suppression). The second menu can only be accessed by pressing two buttons at once (menu and phase), which provides some low-level security, to prevent unauthorised tampering. It deals with the initial set-up (horizontal and vertical picture positioning, white balance, control lock, BPS level and switching for remote aspect ratio switching  and brightness adjustment.  The third menu is for resetting all picture and set-up parameters back to the factory default, it can only be accessed by holding down two front panel buttons at switch-on, which again provides a modicum of protection against accidental or deliberate fiddling. All settings are stored in a non-volatile memory.   


Most functions are fairly self-explanatory, though the BPS facility is worth a quick mention. It’s purpose is to reduce peak whites in the picture area, primarily to prevent screen burn, but we suspect it will also to help reduce operator fatigue, by taking the edge off bright parts of the screen, without compromising contrast. Switchable aspect ratio is also rather unusual. Normally the monitor will be set to 4:3 mode -- i.e. the picture is 4-units wide by 3-units deep -- this is also known as Academy mode and is the current accepted standard format for video and TV displays. However, possibly with one eye to the future, the TM-1700 additionally has a 16:9 or ‘widescreen’ display mode, which superimposes black bars at the top and bottom of the screen, and compresses the image in the vertical plane, in other words everything looks short and squat.


This is an ‘anamorphic’ compression, the idea being that it will produce a genuine widescreen display when showing video material that has been shot using a camera fitted with an anamorphic widescreen lens, or more likely, a digitally processed widescreen mode. When viewed on a normal monitor everything in the picture appear to be vertically stretched or tall. When the stretched image is shown on the TM-1700, in 16:9 mode, everything in the picture is restored to its correct proportions.



From a purely subjective point of view the picture looks crisp and bright under a wide range of conditions. The flat screen has a good viewing angle and suffers less than most non-FST monitors from reflections from overhead lighting. The thin screen surround makes the image look larger than it actually is. Picture linearity and focus are both spot-on and maintained right to the edges of the screen. The quoted resolution of 550 lines -- using a Y/C input -- is feasible under ideal conditions; we achieved 500 lines without any difficulty, using a high performance black and white camera. Colour fidelity is very good indeed, and the broad range of chrominance adjustments should make it possible to compensate for most simple camera errors and variance in scene lighting.


Colour purity was fine at switch-on. We deliberately magnetised the screen, using a small bar magnet; the automatic degauss circuitry was able to completely remove the staining by the third on/off cycle (allowing one hour intervals for the set to cool down). Overall the picture is clean and very stable.


There is a quite noticeable difference between composite video and Y/C inputs. A small improvement in resolution is evident and cross-colour effects, on and around patterned areas, are virtually cancelled out. Vertical edges also look a little crisper, with less fringing.


The built-in speaker is quite small and the side-facing grill could be problem in some tightly enclosed installations. Volume levels and frequency response are adequate;  audio output is sufficient to be heard above the background noise in a busy office or control room. A separate switched line-level audio output would have been useful, if for example  the monitor was being used as a simple switcher, though that’s not a normal operating mode, and in any case both audio channels have their own output connectors.   



A slick and well presented monitor, with no particular foibles or bad habits, in fact we had to dig pretty deep to find anything negative to say about the TM-1700. In the end the only gripe of any substance whatsoever is the lack of a single line-level audio output, though that is tenuous to say the least. General picture performance is very good indeed, with no visible defects or signs of misalignment. All in all a very competent, easy to use, high-performance colour monitor with reliability and a long service life written all over it.



Design and design features              *****

Circuitry and components                  ****

Ease of installation and wiring    *****  

Range and variety of functions            ****     

Accompanying instructions                   ****                             

Technical advice and backup            ****     

Value for money                         ****                           




Ó R.Maybury 1997 0707



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