HomeSoftwareArchiveTop TipsGlossaryOther Stuff











Name  Jilly Pearson, Norwich

Kit            Rediffusion 564358 television

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.



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 whole system.


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.



Name  Ian Parker, Buckhurst Hill

Kit            Pioneer 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

Problem            Intermittent 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.



Name  Julian Shea, Bristol

Kit            Echostar 900 satellite receiver

Problem            A 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.



Name  Jamie Halford, Dublin

Kit            Harmon Kardon AVR10

Problem            Jason 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?



Name  Gillian Mitchell

Kit            Technics AV500

Problem            A 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, Oldham

Kit       Sony MHC-901AV DPL system, Hitachi VT-F550 VCR, Goldstar CF-28C22 NICAM TV

Problem            Neil 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










[Home][Software][Archive][Top Tips][Glossary][Other Stuff]

Copyright (c) 2005 Rick Maybury Ltd.