HINTS & TIPS
YOUR QUESTIONS ANSWERED
ODOUR THE HILL
Name Jilly Pearson,
Problem Jilly wants to know if itís worth repairing her faithful
old TV, which recently went on the blink after emitting a foul stench, which
she describes as smelling like a Ďdead cat, boiled in rotten eggsí...
Expert Reply Good
description. The smell is almost certainly the result of a burnt-out tripler.
Itís an electronic device, that boosts the EHT (extra high tension) supply voltage
needed to drive the picture tube, from just over 8 thousand volts, to 25
thousand volts. Inside the tripler on your set thereís a number of selenium
diodes, encased in a jelly-like insulating material; it stinks to high heaven
when it burns. The trouble is your set is probably getting on for 20 years old.
Whilst spares may still be available, itís well past its economical repair
date, other parts are sure to fail as well. Count yourself lucky; the
life-expectancy of TVs made in the seventies and early eighties was around
eight years, so youíve had more than your moneyís worth. Give it a decent
burial at your local amenity tip and buy a new TV.
HOW GREEN IS MY SYSTEM?
Name Malcolm Greenhill, Walthamstow, E. London
Kit Philips 32W962B
TV, Grundig GV-450 VCR, Grundig satellite receiver, Yamaha DSP-E200DPL amp
Problem Having spent
the best part of £3000 on his AV system, Malcolm is curious about how much itís
costing him to run, and if itís a lot, would it be worth replacing any of his
older, less efficient components?
Expert Reply Donít worry, that little lot wonít break the
bank. The most expensive item, in terms of power consumption, is the TV. Yours
is rated at 180 watts, when itís switched on, and 12 watts in standby. Letís
assume you watch it for six hours each day, and switch it off every night, (so
itís not on standby). That works out at 1.08 kilowatts/hours per day, times 365
days, equals 400kw/hours, all but. London electricity prices are currently 7.3
pence per unit (kW/hr), so that comes to a grand total of £33.80 (including
VAT). The VCR isnít too bad; it consumes 20 watts in the play mode, and 10
watts in standby, which is all time itís not being used. If you use it for
three hours a day, that works out at 0.27kw/hr per day, or around 100kw/hr a
year, which is getting on for £8.60 per year. Reckon on around the same for the
satellite tuner, and £20 or so a year for a well-used,
moderately powerful AV amp, and youíre looking at something like £70 for the
More recent TVs are a little more energy efficient, but the
cost-savings would be negligible, and you wouldnít see a pay-back in the
lifetime of the set. The power consumption of VCRs, satellite receivers and
amplifiers hasnít changed significantly in the past few years, so thereís not
much you can do to save money, apart from turning down the volume, and using
them less often.
NO NEED FOR NICAM?
Name Ian Parker,
VSA-303 DPL amp, Polk RM5000 speakers, Panasonic HD650 NICAM VCR
Problem Ian wants
a new 28 to 32-inch TV, but doesnít think thereís any point in duplicating the TV
tuner and NICAM decoder in the VCR. He want to know if his money would be better
spent buying a high performance colour monitor?
Expert Reply You will
have a tough time finding a decent-sized video monitor this side of a couple of
grand, even then you would notice little improvement in picture quality,
compared with a similarly-sized TV. Whatís more it would limit the flexibility
of your system; for example, you wouldnít be able to record a TV programme,
whilst watching another channel. As far as weíre aware there arenít any
NICAM-less big-screen TVs around at the moment; the market would be very small
and itís simply not economical for manufacturers to make them. In any event a
NICAM decoder, stereo amplifier and speakers adds comparatively little to the overall
price of a big TV. If you donít like the sound the squitty little speakers
produce -- and we must admit most of them are a bit tinny -- you could always route the TVs line audio
output through your AV system.
Name Justin Farrow, Sydenham
Kit JVC AV-28 TV,
JVC 610 VCR
wavy lines and a broken picture, when watching programmes recorded on his VCR in
the past few months have been annoying Justin; he wants to know if thereís a
fault in the VCR?
Expert reply Thereís
some good clues here. As the problem has only become apparent recently, and itís
not affecting your normal TV reception, weíd be prepared to bet youíre
suffering from premature Channel 5 interference. Youíre fairly close to the
Crystal Palace transmitter in London, which has been conducting sporadic C5
tests at various times of the day. Channel 5 will be broadcast on UHF channel
37 in that area, right next door to channel 36, which your VCR uses, to send
signals to the TV. By now you should have heard from the C5 retuning service.
Theyíre touring affected areas, resetting the output frequency on an estimated
10 million VCRs. If they havenít dropped a card through your door by now, give
them a call on 0541 555 551. If you want to do the re-tuning yourself, youíll
have to wait until regular broadcasts begin, which probably wonít be until
early February. All you have to do is adjust the small screw on the back of the
VCR, next to the aerial sockets. Turn it a notch or two to the right (selecting
a higher channel), then re-tune the TVís video channel, to get a clear picture.
Better still, connect your VCR to the TV using a SCART lead, that way you will
get a better picture, and stereo sound from your TVs speakers.
ON THE CARDS
Name Julian Shea,
900 satellite receiver
mate of Julian has offered him a pirate BSKYB Ďsmart cardí for £80, that will allow
him to view all of their channels. Heís seen it working and wants to know if he
buys one, will there be any comeback?
Expert Reply Apart from it being illegal you will loose your
£80, and be rewarded with a blank screen, probably in a couple of weeks, maybe
less. Numerous clever methods have been devised to unscramble the Videocrypt signals
used by BSKYB (and various other satellite channels), but usually, as soon as
they go on sale the boffins at BSKYB come up with ECMs or electronic counter
measures. Channel piracy used to be rife, thereís even PC software on the Internet,
with instructions on how to connect a home computer to a satellite receiver, to
enable it to decode scrambled channels. It doesnít work anymore, ECMs are normally
devised within days or at most a few weeks of the pirate software appearing. Last
year BSKYB changed to a new type of card and encryption system, that has yet to
be cracked. Similarly, pirate cards, which may be clones of a legitimate card, soon
find their way into the hands of BSKYBí encryption engineers, and they quickly
invalidate all the cards with the same code number, rendering them useless.
SNAKE OIL SPEAKERS?
Name Jamie Halford,
has just brought his AV amplifier, which he is using successfully with a set of
JPW AP3 speakers from his previous hi-fi system. He wants to know if thereís
any benefit in replacing them with purpose-designed AV speakers
Expert Reply At the top-end of the home cinema market, with
THX equipment, there is a very good case for using specialist speakers, designed
for the job. With Dolby Pro Logic systems thereís no special constraints on
speaker design, apart from the need for magnetic shielding on speakers that are
placed close to the TV screen. Normally this only applies to the centre-front
channel enclosure, the main stereo speakers will usually be too far away -- a
foot or two -- to have any effect. If they are causing problems you will see
colour Ďstainingí along the edges of the screen, in which case try moving them a
little further away, or start thinking about a set of magnetically shielded AV
speakers. But if it Ďaint broke, why fix it?
MIX OR SEPARATE
Name Gillian Mitchell
salesperson in a well-known hi-fi dealer has told Gillian that the Sony
TA-AV790 is a good buy, but she shouldnít use the video connections on the back
of the unit, as on their showroom set-up the audio and video signals interact
with one another, reducing both picture and sound quality. Is this true?
Expert Reply Hogwash! The video connections on this device
are there merely for convenience, video signals simply pass in and out the box,
without going anywhere near sensitive audio circuits. It is possible for audio to
interfere with the picture in a home cinema system, thereís usually a slight
textural change, or some picture instability, that varies in sympathy with the
sound, but nine times out of ten this is caused by vibration. A large speaker
close to a stand, supporting a VCR, for example, may generate sufficient mechanical
energy to upset the delicate components inside the machine, or the tape itself,
and make the picture judder slightly. The solution is to insulate the VCR or
stand, move the speakers further away, or turn down the volume. Our guess is
thatís whatís been happening on the dealerís showroom set-up.
Name Neil Pashby,
MHC-901AV DPL system, Hitachi VT-F550 VCR, Goldstar CF-28C22 NICAM TV
wants to know how he can tell when a movie or TV programme has a Dolby Surround
sound track. Are there any indications or signals that his, or any other system,
can respond to, so he doesnít have to keep switching it on and off.
Expert Reply Sadly
no, itís not like NICAM or an FM stereo broadcast, thatís electronically Ďflaggedí.
The only way of telling is to watch out for the Dolby logo at the start of a TV
programme. ITV, C4 and BSKYB are fairly good at this, the BBC still have a long
way to go, and quite often the only way of knowing whether a movie theyíre
showing has a Dolby Surround soundtrack, is to look at the end credits, though
even thatís no guarantee, as the broadcast version may well have had a mono
soundtrack. However, you can usually tell quite quickly by listening, just leave
the decoder on your system in the Pro-logic
mode when you use it for AV. Itís also a fair bet that any movie made prior to
1975 wonít have a surround-sound soundtrack, and itís only been used on TV
programmes in the past five or so years.
R. Maybury 1996 0110