|
JVC SR-L910EK 24-HOUR TIME-LAPSE VCR
COPY
WHAT OUR EXPERTS SAY...
Modern electronic devices and manufacturer's quality control
procedures are generally pretty reliable nowadays and it is quite unusual for a
product not to work the first time it's powered up. It's so rare in fact that
when a piece of equipment appears not to be functioning properly, sometimes the
last thing you suspect is a fault. Quite often it's a hidden or overlooked
control function, an external cause, or the user trying to be clever and not
remembering to RTFM*…
Unfortunately that's not always the case; we'll come to the
fun and games we had trying to get the JVC SR-L910EK 24-hour time VHS lapse VCR
to work in just a moment, but first a swift run down of the headline features.
It is a compact design, around two thirds the width of a domestic VCR but with
the same basic layout, namely a centrally mounted deck mechanism with a display
and control panel underneath, flanked on both sides by more control buttons. On
the rear panel there are two BNC connectors for composite video input and
output. There's a pair of RCA/phono sockets for line-level audio in/out, two
minijack sockets for a microphone input and corded remote control (optional),
plus a 10-way spring terminal for the alarm input/output connections plus
various housekeeping and control functions. It has three video recording and
playback modes: 3-hour real-time and 12 and 24-hour time-lapse modes; sound is
recorded at all three tape speeds.
The L910 has a fairly routine assortment of alarm functions.
When it receives an external trigger the VCR switches from time-lapse to 3-hour
real-time recording mode for a pre-set period of 5, 15, 30, 60, 120 or 180
seconds, alternatively it will record to the end of the tape or it can be reset
manually. At the same time an index code is recorded on the tape, a buzzer
sounds (this can be disabled), a flashing indicator appears on the front panel,
the alarm output on the rear panel is enabled and the time and date of the
first and last eight events are logged. Alarm recordings can also be initiated
from standby/stop and timer recording mode; the latter can be programmed to
make from one to eight timed recordings up to 365 days in advance, or at the
same time on a specified day (or days) every week.
Additional facilities include a deck mechanism based on a
rigid die cast aluminium chassis, repeat recording (i.e. automatic rewind and
record at tape end), series recording (tape end on one L910 triggers start
record on another machine), camera switching (when used with an external
switcher) and auto Recording Check. This replays a short section of a recording
at the beginning of a tape, measures the off-tape FM signal and if it falls
below a pre-set threshold, the tape heads are automatically cleaned. The test
is repeated and if it fails again an error message appears on the display.
Recording continues however, ensuring continuity of coverage. Recording check can
also be engaged manually at any time by pressing a button on the front panel.
OPERATION
And so we come to our little spot of bother. Everything
looked fine when the L910 was connected to a monitor and plugged in for the
first time; the front panel lit up with the correct time and status displays,
so it was off to a good start. After loading a protected resolution test tape
the deck laced up and started playback but nothing appeared on the screen. No
picture, no time or menu display, just a blank raster. Peculiar, VCRs always
work straight out of the box, so it must be a duff tape? Wrong, another tape
was tried and the screen remained blank. Could it be a security function, a
control lockout or anti tamper feature perhaps? Time at last to read the
instruction book… It turns out the L910 does indeed have a control lock, but it
couldn't be responsible for this problem otherwise the tape transport functions
wouldn't have worked.
So, it must be a lead or connector? They were all checked
and swapped around, still nothing. Then we noticed a flashing indicator on the
display panel showing 'E-11' (we did spot it earlier but thought it was
something to do with tape length at first). A quick check of the
troubleshooting appendix revealed this to be an error message indicating no
video input. Aha, so it needs a video input to work, we were already mentally
knocking off points for what seemed to be an obvious design flaw (in fact it's
a helpful video loss indicator, so the L910 score sheet wasn't affected). A
colour camera was duly connected and a picture appeared on the screen. Problem
solved, or so we thought, there was still no playback function or displays.
Having eliminated all of the apparently obvious causes the only thing left was
a fault on the VCR.
Before calling JVC for some technical help we whipped the
lid off. Everything seemed to be in order. In common with most other VCRs the
largest component in the box is the deck mechanism and this continued to behave
quite normally. The deck sits on a sparsely populated motherboard in the bottom
of the case; three daughter-board PCBs plug into the main board, all of the
cables and connectors were in place and nothing appeared to be loose or adrift.
Finally, before switching off to replace the lid and we gave each of the
daughter-boards a gentle prod. There was no change until we came to the last
one -- on the left hand side of the case -- when tapped a numerical display
flickered briefly on the screen. Pressing down on the board there was a
reassuring click as it seated in its sockets and normal operation was restored.
It was a simple enough fault and rare enough not to be a
concern so there are no great truths or insights to be drawn from this episode.
Nevertheless it was a timely reminder that it's easy to overlook the obvious,
and that even companies with a normally excellent track record in quality
control can occasionally slip up.
With normal service resumed it was back to the matter in
hand. The control layout is function though not particularly ergonomic or especially
easy to use. The main transport keys are grouped together on the left side of
the front panel, all secondary functions and the on-screen display (OSD)
buttons are below the tape hatch. The buttons are small, they are all exactly
the same size and the light grey on slightly darker grey labelling isn't
especially easy to read. The main menu opens with six choices, (Program Timer,
Function, Alarm In, Power Loss, Hour Meter and Clock Set); in most cases
selecting an option takes you to a set of sub-menus covering the VCR's various
set-up and control functions.
Getting the machine up and running takes no more than a few
minutes; adjusting the clock is the first job. The clock set menu brings up a
simple time and date display that's altered using the bank of set/shift buttons
on the front panel. As a matter of interest the clock is fully Y2K compliant
and is programmed to operate until the year 2096 -- JVC are clearly very
confident of this machines durability... Incidentally the SR-L910 also recognises
that the year 2000 is a leap year; apparently some date-sensitive devices do
not and it may well be worth checking any equipment in your care! The remaining
installation options are accessed from the Function menu. They include OSD
position (one of the four-corners of the screen or off), sharpness (normal or
sharp), video mode (auto/colour/black & white) and tape end mode (rewind,
repeat, eject or stop). The alarm settings are also included on the function
menu, along with switches for the internal buzzer and presets for Summer time
adjustment, external camera switching and record time-remain indicator. An hour
meter records the time the head drum is moving in hours, the instruction manual
gives some brief guidance about service intervals and the replacement of lifed
components. We discovered entirely by accident that the hour meter can be
easily reset, fortunately 'clocking' time-lapse VCRs has yet become a
problem.
Once the basic settings have been entered it only remains to
load a tape and select the recording speed. This can be changed at any time,
without having to stop the tape. The normal on-screen display shows time date
and recording speed. Playback options include normal speed replay, at the speed
the recording was made (or one of the other recording modes), reverse play,
still frame/field and 9x normal speed picture search. Alarm events can be found
quickly using Index Search; the tape fast-winds to the start of the recording
and automatically goes into replay mode as it detects an index marker. An
RS-232C interface board is available as an optional extra, this enables the VCR
to be controlled and its status monitored from a PC.
Installation and connection to an alarm system or sensor
should be very straightforward in the vast majority of cases. The rear-mounted
spring terminal is quick, easy to use and reasonably secure.
PERFORMANCE
After an initial 24-hour soak -- to make sure that the loose
board hadn't caused any other problems -- the L910 was subjected to our usual
range of VCR tests. Using a high-grade tape our sample managed to resolve a
little under 250-lines, which is close to the limits of the VHS performance
envelope. This was unaffected by recording or playback speed, though for
obvious reasons picture stability did tend to suffer in the time-lapse modes.
Replaying a recording at a non-standard speed -- i.e., a 3-hour recording in
12-hour mode replay -- did result in a further loss of stability and a big
increase in noise interference. Picture noise levels were very low indeed and
the machine did seem to benefit from the use of HG tapes. Colour fidelity was
also very good with dot crawl only becoming apparent in areas of high
saturation. Still frame stability was excellent and it is possible to step
forwards through a recording -- one frame at a time -- without any significant
jitter. For some reason there's no reverse frame advance facility, which makes
finding a particular frame quite difficult. In fact the relative coarseness of
the picture replay controls is a disadvantage when analysing a recording and
the machine would greatly benefit from some kind co-ordinated multi-speed
replay system.
One rather unusual and potentially troublesome quirk of this
machine was the way it recorded on-screen menus and displays. This doesn't normally
happen. Displays are normally superimposed on the video signal during the
latter stages of processing, after it comes off the tape. There is no obvious
advantage in being able to record the OSD; in fact the opposite is the case. It
is possible that the menu could be inadvertently left on the screen, or put
there accidentally, and not seen (the monitor may be switched off or the
machine set up for unattended or timer-programmed recording; the OSD will be
burnt into the recording and possibly obscure important detail.
Audio is recorded on the standard VHS mono linear edge track
and in the 3-hour mode it's as good as anything you'll hear on a decent quality
domestic mono VHS video recorder. The upper frequency limit is quite modest --
in hi-fi terms -- but it's more than adequate for speech and incidental sounds.
There is a significant increase in noise and a big reduction in treble response
on 12-hour mode recordings but it is still adequate for speech -- providing a
sufficiently sensitive microphone is used. The 24-hour soundtrack carries
predominantly loud bassy sounds, it is just possible to make out speech, though
don't bank on it.
OVERALL ASSESSMENT
We're inclined to overlook the loose daughter-board. It's
not a design flaw -- the board stays put once latched into place -- it might
indicate sloppy QC procedures but JVC are normally very reliable in this area
so this is probably just an uncharacteristic one-off. Nevertheless the machine
does fall down on a couple of points. The first is the rather poor assortment
of replay options. A lot can happen in a just a couple of frames of a
time-lapse recording so it is important to be able to analyse a recording in
close detail, and the only way to do that is with quick and responsive forward
and reverse frame advance and slow motion replay. The L910 has forward frame
step, normal speed play and reverse play, consequently reviewing a short
sequence of tape can be very frustrating. It's not helped by the layout of the
tape transport keys and more often than not you find yourself whizzing past the
bit your want to look at. The second problem concerns the recordable on-screen
display; this has the potential to go unnoticed and could easily result in the
loss of valuable information.
There's still a lot to commend this machine. Video recording
quality is very good indeed and it compares well with rival 24-hour and
longer-duration time-lapse VCRs. It is compact, simple to install and
reasonably easy to set up and use. Build quality -- apart from our little
hiccup-- is good and the solidity of the deck mechanism bodes well for long
term reliability. Putting our misgivings to one side for a moment this VCR,
like it's rival from Philips, is a cost-effective surveillance solution for a
lot of retail premises and small businesses, where 24-hour coverage is
appropriate and the facility to record sound could prove useful. It's difficult
not to like the L910, but you can't help feeling that if the few rough edges
could be ironed out, it would have been so much better.
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 ***
* read the f***ing manual
---end---
Ó
R.Maybury 1998 2809
| 
