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Reliability of satellite receivers

Something which you will not see mentioned in print very often is the reliability of satellite receivers and decoders. I've repaired well over twenty thousand so I have a pretty good idea which are reliable and which are not. However, I am not going to risk court action by naming names! In any case, reliability is not the only consideration. Sometimes it can pay to buy a receiver which is less reliable, provided you know that the manufacturer will look after you if things go wrong.

There are, however, certain things which you can do to minimise reliability problems. The most important of these is to KEEP IT COOL. I am continually amazed by the places people find to wedge a satellite receiver, giving it no chance to stay cool. The favourite is on top of a nice warm video recorder, inside a cabinet with the doors shut.

Let me digress to explain a little of the technicalities. In most satellite receivers, the component most likely to fail is the electrolytic capacitor. To keep costs down, manufacturers often use capacitors rated at 85 degrees Centigrade. This means that the capacitor will last for roughly 4000 hours at 85 degrees, which works out at less than 6 months! Luckily, most satellite receivers don't achieve anything like this sort of temperature so they last a lot longer - usually at least twelve months and one day, even if you abuse them. :o)
A common question is "why do satellite receivers run so hot?"

Satellite receivers tend to run hotter than, for example, a video recorder because:

  • A tuner running at a high frequency uses (and wastes) a lot of power.
  • A satellite receiver is usually on top of or above the video recorder.
  • A satellite receiver usually has less internal air space and smaller vent slots.
  • A satellite receiver is still powering most of the circuitry even in "standby".
  • A video recorder has moving parts or even a fan which circulates the air inside.

The answer is to install it on an open shelf or table to give it plenty of air space. Make sure that you do not allow things to be placed where they will block the ventilation slots. The most common offenders are magazines, plant pots and pets. The latter two have the added disadvantage of leaking!

If you absolutely MUST fit it inside a cabinet or inside that made-to-measure slot in your custom fireplace, the only answer is a fan. Only a gentle breeze is required, provided that it draws air through the unit. Fit my Miniature Cooling Fan kit.

>Dear Martin,
>I have today fitted a relkit10 to my Pace MSS508IP, I am glad to say that it
>has cured the problems of white diagonal lines moving across the picture and
>the motor overload messages that stopped my motorised dish from moving.
>Having no real electronics knowledge but the ability to use a soldering
>iron, this kit and the diagnosis obtained from your website enabled me to
>fix my receiver quickly and cheaply. The only thing I have not worked out is
>how you managed to get all of the receiver manufacturers to fit sub-standard
>components that fail so predictably!

Ha ha :o)

I do keep phoning them to thank them. ;o)

Basically, they are all "tied to a price" and have to buy very cheap components. Electrolytic capacitors range from cheap to expensive, dependent on what reliability you want. You can pay ten times as much to get only double the life expectancy. Modern central heating and the user's amazing ability to stack everything and place it inside an "oven" will guarantee the need for my kits. All electrolytic capacitors have a limited life which is largely determined by temperature. If you can pin the manufacturer down (not easy if you don't speak Chinese!) he will often give you a specification such as "2000 hours at 85'C". The receiver maximum internal temperature is probably no more than 30'C, giving a life of maybe 6000 hours. This sounds less reasonable when you divide 6000 by 24 = 250 days!!

But now consider that a small reduction in capacitance will not have any apparent effect so the effective "life" of a capacitor at 30'C is more like two or three years before you begin to notice a deterioration in picture or sound quality. At 20'C it could be six to ten years.

Even the most expensive electrolytics contain a wet electrolyte and will fail eventually.

So my fan kit really does provide a good solution as it probably doubles the life of the capacitors. It removes the "hot spots" of stagnant air, effectively reducing the temperature to little more than ambient room temperature - say around 25'C. The only problem with fitting a fan is that the electrolytics must be new in order to benefit; reducing the temperature of electrolytics that have already deteriorated has the effect of lowering the capacitance value permanently. That is the cause of so many "failures" after people have unplugged the equipment while they went on holiday.

Liquid - death to electronics!

Apart from plant pots and animals, another source of moisture is rainwater running down your TV aerial cable. Get your installer to check that this is impossible. The other moisture problem (apart from beer and coffee) is, believe it or not, polish! Many people seem to think it is a good idea to spray polish onto a satellite receiver. Unfortunately, many of the polishes contain water and some also contain ammonia which has the same corrosive effect as a leaking pet. So DO NOT spray polish on your electronic equipment. I would advise using a little oil-based water repellant such as "WD-40" on a dry cloth. This will both clean and polish without damaging the plastic or the internal parts.

If liquid should be spilled inside accidentally, immediately disconnect the mains power. Use a hair dryer to remove all traces of liquid inside then leave the unit in a warm place for at least a day before applying power again. You might just save it by using this method. No reputable repairer is likely to accept a liquid-damaged item for repair because, even if he manages to replace the corroded parts, the future reliability (and safety) usually can not be guaranteed.

A less common problem which will "kill" a satellite receiver is the mains power surge. This can be caused by the use of an electrical power tool nearby as well as by stormy weather. You can achieve good protection against power tool surges by fitting a spike suppression plug. These are often sold for use with computer systems. You need not wire it in. Simply insert the spike suppression plug into an adjacent socket in the same wall plate or adapter.

There is no real defence against electrical storms and the surges can take one of several paths. A mild surge on the mains power supply might be grabbed by the spike suppression plug but a large one will not. It is better to disconnect the equipment from the power socket. Switching the socket off may be inadequate. You should remove the mains power plug and place it away from the socket.

Another path is via the Television aerial or via the dish cable. A direct lightning strike is extremely unlikely so please don't worry about it. What is more likely is that dust particles outside are charged by the proximity of a storm. The dust is swept past the aerial and dish and deposits electrical charge on these. This charge can build up until it is sufficient to create a tiny spark. After pulling out the power plug before a storm, you should disconnect both dish and aerial cables. Place the ends well away from the equipment; preferably behind a water-filled metal radiator or pipe but NOT near a gas appliance or pipe!

These actions will protect your equipment but it might then fail when you plug it back in! It seems that you just can't win. Equipment which has been running warm for some years will often fail if you let it cool down then reapply power. This is almost always caused by those electrolytic capacitors mentioned earlier. Replacement kits are available for several satellite receiver models. Prevention is usually cheaper than repair, however power supply repair kits are also available. These should be fitted only by an experienced person.

Finally, NEVER replace a melted fuse without first replacing the cause of failure, otherwise you could make the damage worse and put yourself in danger.

Martin Pickering can be contacted for advice about satellite receiver repair via the Internet.
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Copyright ©1997 SatCure
Version 1.4 updated on December 26, 1999
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