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JVC TM-1700PN-K COLOUR VIDEO MONITOR
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WHAT OUR EXPERTS SAY...
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.
OPERATION
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.
PERFORMANCE
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.
OVERALL ASSESSMENT
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.
PRODUCT ASSESSMENT
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 ****
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Ó R.Maybury 1997 0707
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