Interview with Marc Vandeputte (Philips)

PACKED: How long have you been working for Philips? And what is your position in the company?

Marc Vandeputte: I have been working for Philips now since 1983. I started in the final assembly of colour televisions. After four years I became part of the design maintenance group and later on, I became responsible for a specific range of CRT TVs, a so-called set father.
Today I am still doing this job in the Development Quality department. I work with four colleagues, covering the complete Philips 8000 and 9000 series of flat TVs. As a team we create parts lists, generate test specifications and execute the corresponding quality test plans. We do the top-down validations of the sets.

The flat screen TV is a mechanical embodiment of a powerful platform built with electrical hardware and controlled by huge software algorithms. All those individual parts are created - according to specified requirements - by an enormous development team. To cover the complete commercial versions and executions, it is important to know the specifications, to know the hardware functions and the software to control such according selectable options. Every piece of this puzzle must fit perfectly to produce, for each individual class of set, the best picture and sound and also easy access to the complex functions that a flat screen TV is capable of dealing with. The goal is to fulfil the ’Sense and Simplicity‘ statement of the Philips Consumer Lifestyle sector.

 

PACKED: Do you keep a television collection here at the Philips centre in Brugge?

Marc Vandeputte: Yes, we have a lot of old televisions from 1957 to today here at the Philips centre in Brugge. The principle reason why we have these televisions is that the law requires that every television that is brought onto the market must be released by an organisation with a national accreditation for both testing and certification and if something happens with the product, they must be able to go back to the original reference model and check it. The approbation model must remain available for up to seven years after the end of production. Also for the service department it can sometimes be useful that they are able to refer to us for any difficulties that need resolving. For such cases we have easy access to the TV type involved. In Belgium for example we have CEBEC that has a national accreditation for both testing and certification, and in the Netherlands there is KEMA. Every country is given a sample from Philips that it can test according to its own safety standards. If the television set is considered safe it will get a certificate with a number for a production licence according to such standards. This certificate allows Philips to produce the television set and bring it onto the market. The certification is made visible on the identification plate of the television set on which one can find the symbols of all countries that have given their permission for the product to be brought onto the market. Each time Philips modifies something, it must inform these national organisations such as CEBEC. They then re-check whether the television is still safe. For example in the case of a fire, on the rare occasions when it is clearly visible that the television set itself is the source of the fire, they will check if the model that caused the fire was made according to the standards. One cannot bring a product onto the market easily; it must be made according to these standards.

 

PACKED: Do you also have televisions that are over seven years old in your collection?

Marc Vandeputte: We have a lot of television sets, and all of them still function. The total number of CRT based televisions is now decreasing because old televisions are very bulky and it takes a lot of space to store them. I had to make a selection and so have only kept one per range or family from each time period. We have fewer CRT televisions and more flat screen TVs now, but there are some museum pieces that we want to keep. I've kept a model from each decade and type: 1960s, 1970s, 1980s, 1990s, black and white, colour, widescreen, 16:9s and then the real flat screen TVs but still based on CRT and from 1997 onwards real flat screen TVs based on plasma, LCOS and LCD technologies. At first it was not easy to create a television collection because it takes up space, and the collection must be moved regularly because here at Philips the departments move internally every now and then. Luckily I was eventually told that I would be given a specific place to store the old television sets. Now this room is also filled up with the recent models from the last seven years. If we have enough space we will try to keep them all as long as possible. As part of my hobby - repairing old TVs - I've also restored a 1957 television set that I received from an elderly person. I keep it at home. It was one of the first black and white TVs made here in Brugge.

 

 

PACKED: Museums are experiencing problems with art works using equipment such as CRT televisions and videotape players that are becoming obsolete. We are trying to find out what should be done to keep this equipment functioning as long as possible.

Marc Vandeputte: Of course. Nothing lasts forever. If something breaks or fails one needs the skills and the equipment to troubleshoot it and one needs the components or spare parts to repair it. For older sets (older than seven years) it might become problematic... I’m familiar with this problem of the obsolescence of spare parts. First of all you have the spare parts problem: some key components from old televisions and also the industrial equipment and resources are no longer available. In some cases they even have to be reproduced by hand. A good example is the high voltage transformer, or the so-called LOPT (Line Output Transformer) that generates 27kV from 140V to drive a part of the picture tube. If this transformer is defective you cannot replace it by a different one when the same model is no longer available. The only solution is to have it remade. You can ask some OEM manufacturers that are still producing high-voltage transformers to make a copy of it with the same specifications. It will cost you a lot of money, but you will have a pseudo-original transformer to put in place again and have your television running for a longer period of time. If you want to preserve an art work for a long period of time, the best strategy is to start collecting spare televisions, tape recorders, etc now while they are easy to find - new or second hand... and to find a technician who might eventually be able to fix for example one television from five identical but broken ones by re-using components that are still working. Secondly, the equipment must be stored in a conditioned room, where humidity is kept as low as possible. Regular – once a month - use of the equipment keeps some sensitive electrical components such as electrolytic capacitors ’fresh‘.

 

PACKED: The problem for museums is that sometimes, and this is the case for CRT televisions and monitors, the whole technology disappears.

Marc Vandeputte: Yes, I understand the problems that are experienced in your field. We will face the same ones here with my old televisions. (Laughs). The older technology disappears due to the lifetime of components used. The carriers that contain the picture and audio might live longer, but the equipment to play them will, in the end, disappear… Today Philips, and all the other brands as well, is into the digital world, although analogue is still treated as important: almost every TV today, as well as equipment connected to it, still has analogue inputs and outputs in order to remain compatible with older equipment such as VCRs, DVD players, analogue cameras, etc... People with a new Blu-ray disk player can still hook up to an old TV or a new flat screen TV. Both televisions can also handle signals from the old-fashioned videocassette recorder.

There are a lot of countries where, although the network is digital, you have a set-top box that transforms the digital signal into an analogue one for old televisions with SCART and RF connections. In the end, no set-top boxes will be required after the last analogue TV has “died” and the total chain will only be digital compatible. Older TVs and monitors stored in museums will require analogue compatible equipment… For myself – to service old analogue TVs - I have bought some basic repair equipment that still supports the analogue world, such as a PM5518 test pattern generator. I bought it to repair and re-align defective older televisions. Sometimes the repair requires a new alignment of a few circuits in these televisions to their original specifications so that they can once again produce a good picture. The signal distribution is digital now almost everywhere but the internal signal distribution is still analogue in an older television. We can attach an antenna or cable and still see a picture or just get some noise... Analogue is still available in some countries but within a maximum of five years all analogue signals from TV signal providers (cable distributor companies, e.g. Telenet) will be gone: we will need a tuner-decoder to transform the digital signal into a compatible signal for older televisions. We already have DVB-T or DVB-C, even DVB-S.1 When I switch on any old television, I'll only see noise on the picture tube. In a museum one can modulate the signal of a modern DVD player with an old analogue modulator simulating an antenna, and then send it to the television’s tuner or aerial input to get a picture or simply connect it via SCART, if the old TV has such a connection. It is also possible to fake it. Old television casings with new electronics inside are still possible but maybe this is not what museums want.

 

PACKED: In some cases it is. Museums are not only dealing with the problems of display equipment like monitors but also with the problems of playback equipment. Faking the device can sometimes be the only solution. Often the old video players have been replaced by, for instance, flash card players that are playing a digital copy of an old analogue video. These small and modern flash card players get connected to old monitors and are sometimes even hidden in old analogue video players.

Marc Vandeputte: If one has the money, one can now buy a VCR-DVD combination for almost nothing, for maybe €100. I would advise one to buy this kind of equipment and keep it for the near and far future… One can use the electronics inside to place in older video recorders. One also has to be a little ‘handy’ to remove the electronics from the old VCR and replace them with new ones, but it is possible. Visitors will not know or notice the trick.

 

PACKED: You propose using new components in old devices as a solution?

Marc Vandeputte: Yes, when possible of course... Not everything new is compatible with the old. In a television for instance the picture tube will unfortunately also break down at a certain moment. The filament that heats up the cathode can break or interrupt and then the picture tube is finished; you cannot replace it. You have to replace the tube with exactly the same kind. Technicians know that there are sometimes close-to-the-original replacements. Philips no longer has any picture tube factories. The only way to find a replacement is to try the Internet... For VCRs, there are uncountable numbers of different video heads. If one is end-of-life, there might be no substitute available anymore...

 

PACKED: Despite everything there is a limit to the lifetime of every device.

Marc Vandeputte: Exactly. Some of the conservation limits of televisions and other equipment are due to nature. The oxygen in the air causes rubber parts in a video player to disintegrate, metals to rust and the UV light to fade the colours of a television casing.

A lot of components in a television set are based on chemical parts, for instance the electrolytic capacitors (called elcaps), which can dry out during operation and even if when not in use. They have a positive (+) side and a negative (-) side just like a battery and if they are not under voltage for a long time they will disintegrate sooner or later. They will behave just like a car battery that goes really flat; one cannot recharge them or return them to their original state. It would be wise - as I said before - to switch on an electronic device once a month and let it play for one or two hours and then switch it off again. That way one can keep all components in a good shape.

 

 

PACKED: Are the elcaps often at the origin of technical failure?

Marc Vandeputte: In a flat screen television there are approximately between 100 and 500 elcaps and if one fails the whole system might fail now and then, or even permanently. But sometimes elcaps can also fail without one noticing because in a television there are capacitors that are there for instance only to prevent radiation to the outside world or to make them insensitive to radiation from the outside to the inside. One could remove maybe twenty capacitors from a television set without any deterioration of its performance occurring. But if one then places it near a mobile phone antenna, one might notice some effects. If one moves the television set two kilometres away from the antenna, one won't notice anything strange anymore. There are really functional capacitors and other capacitors to prevent radiation or susceptibility to transients or under-voltage. Capacitors cannot compensate for over-voltage but they can compensate for under-voltage situations like mains dips. This is a short voltage drop. If one has a 230V mains supply, it can deviate from 196V to 264V. We need capacitors to compensate the voltage changes so that our televisions still perform well enough during these changing conditions. For players like VCRs, mechanical wear can also occur; bearings and springs lose their characteristics, belts break or lose their grip in the pulley. As a consequence the velocity or transport speed of the tape passing along the drum becomes out of balance and the picture displayed will be partly or fully distorted. In older TVs and VCRs a back-up battery is sometimes applied to feed a memory that stores the programmable items that may not be lost for proper functioning. That is why a battery must be recharged before it loses the capacity to supply the memory voltage. Otherwise settings such as option settings, volume, contrast and channels are lost. The battery itself has a limited lifetime, depending on the load, charge and discharge cycles.

 

PACKED: The best thing that can be done for a monitor or a television is to store it in good conditions and then plug it in once a month?

Marc Vandeputte: Yes, switch it on for an hour and then switch it off again, once a month… If an electrolytic capacitor (elcap) has not been put under voltage for a year, there is a high risk it may fail when you switch the equipment on. It is even possible that the elcap used in high voltage circuits might explode if you switch on the television after a long period of non-operation. In low voltage circuits people sometimes experience another problem related to the elcap phenomenon when they come back from a long holiday: they had turned off the mains when they left, and when they get home they turn on their old video deck and it doesn't work anymore. As long as they were using their video deck on a continual basis, they had no problem, but it cooled down during the long holiday break and so when an elcap that was already at breaking point had to suddenly be restarted, it failed. Maybe it would have failed six months later anyway but because of such sudden, increased stress, it crashed earlier.

 

PACKED: If stored equipment is turned on once every month, should it be switched on completely or just onto standby mode?

Marc Vandeputte: I would recommend switching on the equipment completely to be sure that every part inside the equipment receives the power, since an electronic device can be split into different modules, each requiring a different voltage to run on. A video deck for example has a supply module with 230V coming in via the mains cord and it delivers different kinds of secondary supply voltages (+33V, +12V, +5V, +3V, etc.) that all come out of this main supply. If you plug in the device after a longer time and the last status was standby, it will re-power in the standby mode, the power supply will partly work and therefore it will only power the microprocessor circuit that runs on the standby voltage, not the rest of the circuit. A lot of elcaps will not function. So it is better to switch the equipment on completely. Eventually it will go down to standby spontaneously, depending on the software programme. Philips televisions automatically go into standby if they detect no signal after ten minutes.

 

PACKED: Do only the new ones go into standby mode if they detect no signal?

Marc Vandeputte: The very old ones will not go into standby if the antenna is removed. A lot of Philips televisions will switch to the standby mode after ten minutes of noise on the screen.

 

PACKED: What kind of maintenance is necessary when storing this kind of equipment?

Marc Vandeputte: For a video recorder you should press play from time to time (once a month). To ensure that the mechanical parts continue to function, it's advisable to play a cassette and let it run, for example, for five to ten minutes, rewind it, fast forward it, stop the playback and then eject it. Every single mechanical part inside is thus activated, which will prevent the mechanics from becoming blocked.

It is also wise to have the manufacturer’s service manual to check what grease can be applied and where so that one can get the material while it is still available. Grease can dry out. Not every kind of grease can be applied to moving parts, because of chemical interaction. For instance oil can destroy some of the plastics parts used on the inside, which is why I refer to the equipment's service manual.

 

PACKED: For long-term storage, is it important when switching equipment on once in a while to do so with progressive voltage?

Marc Vandeputte: If the switching on is done on a regular basis, then progressive voltage is not necessary.

 

PACKED: Is it better to keep a monitor or equipment on standby permanently than to switch it on and off regularly?

Marc Vandeputte: I prefer NOT to leave it on standby, but regularly to switch it on completely (once a month). In fact, it’s a trade-off: to leave it on or to switch it off. If you leave your equipment on, you will always have to deal with a maximum lifetime of 20.000 operating hours. If you switch it off and on, you will also have a maximum lifetime of 20,000 operating hours but you divide them over several days, weeks, months and years. If you leave your television on for twelve hours a day, instead of twenty-four hours, your television will not last the double because switching the television on and off creates a form of stress which will also affect the lifetime. You may also have a problem when you switch the television from standby to on when it reaches its maximum lifetime.

 

PACKED: Is the expected amount of playing hours still 20.000 hours for a Philips television?

Marc Vandeputte: Yes, Philips calculates that a television will work at least 20.000 hours. Other manufacturers can use other criteria, but we go for a minimum of 20.000 playing hours. We calculate 20.000 hours for a television that is switched on and off several times per day. We consider this and then we calculate for a minimum of 20.000 hours, because for some components the switching on and off procedure is physically stressful, especially if there is electrical power dissipated in it, resulting in a set's heating up and cooling down. One of any of the components might fail after 20.000 operating hours, but one can never tell which. Those that deteriorate the fastest are those that heat the most. Also solder joints are sensitive to extreme temperature variations. Here at the Philips centre we do tests in which we stress the televisions. We don't let them play for 20.000 hours but for around 3.000 hours in a well-defined cycle: we turn them on and off several times in stress rooms while varying the temperature extremely from + °C to - °C. In a shorter period of time we can see what the lifetime will be and what will probably happen. Of course early failures are investigated thoroughly.

 

PACKED: Some failures originate from a long period of non-usage of the equipment. What are the failures that come from extensive use of the equipment?

Marc Vandeputte: In video and audiotape players, the heads are very sensitive to erosion from use. Contrary to the earlier example of the capacitors, some parts cannot be maintained by usage. Especially mechanical moving parts: they have to be kept fit by NOT being used too often. Therefore conservation will always be a trade-off. Bearings, belts, sliders, etc, are subject to wear out. Compare it with tyres...

Even solid state, immobile components can wear out sooner or later: in fact all electrical components have an insulating material that is required when one works with voltages. When it has been in operation for a long period of time, this material loses its characteristic insulating properties. If you have a component with two conductors, one at a potential of 10V and the other at 27kV, you will need a different insulation distance between both. This insulation distance depends on the kind of material that is being used as an insulator and the applied voltage. The higher the voltage, the quicker the insulator fatigues after 20.000 hours playing time. It will become a conductor. One could say that the better an insulator material is, the thinner it can be made. In general, the higher the voltage the better the insulation must be to cover the time span. Apart from the insulation there is another cause of fatigue: chips, transistors and resistors are all chemical components or physical components and they are always stressed during operation. If you put a voltage on a chip, the power is dissipated in that chip and the chip's heat increases slowly from room temperature at 20°C to 110-115°C. The process of switching on and off and changing the temperature from 20°C to 115°C and back again during operation creates thermal stress for the chip. This is also a way to test the lifetime of the components: by switching it on and off to detect the weaknesses. Before people didn’t switch their television on in the morning because there were no broadcasts. Nowadays there's twenty-four hour a day broadcasting. The result is that people switch their televisions on and off all the time. These stress moments make the chips deteriorate. Fifty years ago there were maybe forty transistors in a chip, now we have one million or more on a smaller surface and it becomes more easily defective than in the past due to the increase of stress moments.

 

PACKED: The temperature changes within the equipment and their individual components have an important influence on their maximum lifespan?

Marc Vandeputte: Yes, in the past manufacturers were not satisfied if for instance the chip got hotter than 100 °C because the higher the ’delta T‘2 as we call it, the sooner a chip will deteriorate and become defective. It is important to keep the delta T as low as possible. The bigger the delta T, the more severe the stress on components is. This is the reason why they put fans in some equipment: to keep the delta T as low as possible. Solder joints are also sensitive to thermal stress: the horizontal displacement of the leads of a hot component causes mechanical stress in the solder material. Not only is the delta T is important, but also the voltage, the amount of operating hours, and the operation conditions count. In general: does the device play in an environment of 15°C or 35°C, and in a high or low humidity environment? One would imagine that if a device has to reach a very high temperature, then components would come under stress. As I said before, the higher the voltage is, the shorter the lifetime will be. High voltage components break down more easily than low voltage components. Operating hours are a factor. Nothing lasts forever, with the exception maybe of a copper wire that does not experience stress. But here we are dealing with semi-conductors, resistors and electrolytic capacitors.

 

PACKED: What are the most common defects in a television?

Marc Vandeputte: In order of increasing occurrence: the high voltage components (EHT components), high current resistors, electrolytic capacitors and the solder joints of hot components.

 

PACKED: Are the EHT components really particular to brands or models?

Marc Vandeputte: Yes, all equipment has high voltage components inside when the mains voltage powers them. In general, modern electronics do work on low voltages and therefore can be battery powered, but there is at least an electronic device to charge the battery apart from the old fashioned transformer which brings the 230V mains voltage to a lower workable and safe supply voltage. This function is now realised by an electronic circuit, the so-called power supply circuit. That mains supply is built up of several EHT components designed by or designed for a particular manufacturer. They will probably not fit into another brand, unless it’s a commodity. It might have the same physical dimension but the electrical specifications will no doubt differ and so they are neither usable nor interchangeable...

 

PACKED: Would you recommend collecting spare parts as an important strategy to remain able to service the equipment for a long time?

Marc Vandeputte: If museums want to keep their equipment in working order, they should try to buy spare parts for every equipment piece that they own.

 

PACKED: Would you also recommend collecting electronic components like electrolytic capacitors?

Marc Vandeputte: Electronic components like electrolytic capacitors are still a commodity and can easily be found. I wouldn’t recommend collecting them.

 

PACKED: What do you consider the most important spare parts to collect?

Marc Vandeputte: For televisions and monitors, the EHT transformer and picture tube. Most EHTs and tubes are particular to a specific model. They will disappear from the market, and become more and more expensive. Having power supply components is also advisable. Most of the time they are made as complete modules, easy to replace in case of failure.

 

PACKED: Are the components of a CRT television produced by Philips different from those of a CRT television of another brand?

Marc Vandeputte: As I mentioned before, the transformers in a Philips television have, for example, a certain shape with a certain number of pins, whereas the transformers in another brand might have one or more pins less or more, depending on the model specifications. The supplier will produce the transformer according to the brand’s wishes and requirements. The principle of the transformer in the televisions of the different brand is the same - it generates high voltage and other voltages - but the electrical requirements might differ hence the mechanical pinning will not be the same. If you have a particular television set, you should try to buy that transformer if it is still available. If it is no longer available, you can only hope that it will last for another fifty years. If you buy the EHT transformer and the switching device that controls it, your television or monitor will be safe for many years.

 

PACKED: The switching device?

Marc Vandeputte: Yes, the so-called line transistor. You can always refer to the service manual to find out which type is used in a particular device. Sometimes you can replace it with another one and put in an over-specified component with better specifications than the original one and it will work again.

 

PACKED: What do you consider to be the ideal climate conditions for storing televisions and other electronic equipment?

Marc Vandeputte: I would recommend very low humidity and a stable temperature. You have to prevent the humidity from getting into the equipment. The drier the air is, the better. If a television set is moved from a dry condition to a wet condition environment, or from humid and hot conditions to dry and cold conditions, condensation will gather on the coldest or the metal parts and then corrosion starts. For the temperature I would recommend 18°C. Most equipment is designed to function at room temperature.

 

PACKED: What else can be done to improve the storage of the equipment?

Marc Vandeputte: In equipment like video players and recorders, the rubber belts will decompose. It makes a difference if they are used or not because they are under constant mechanical tension. I recommend releasing them from their small wheels, which would reduce physical stress; what remains is the influence of the oxygen in the air. When the rubber belts in video equipment become old, there are cracks everywhere and just like other rubber bands they will decompose. I am not a belt specialist but I think that the rubber belts should be kept in a void, for example in a plastic bag vacuum. It would probably also be good to keep them in the dark to protect them from UV light.

I have a similar recommendation for the springs. If there is a spring inside the equipment, you should remove it. This will help to maintain its pulling or pushing strength. If springs are stored in a room with low humidity, they won't rust because usually they are already galvanized or conditioned. When you want to use your device, you will have to mount the belts and the springs again. This might be a bit impractical, but it will help to make them last longer.

 

 

PACKED: Should the equipment be stored away from the sunlight?

Marc Vandeputte: Yes, direct sunlight always makes plastic fade because of the UV light and it can create temperature changes.
Talking about temperature changes: if you store a monitor in a place where it is 10°C in winter and then play it in a room where the temperature is 25°C, you should allow for the monitor to accommodate before you switch it on. If you don’t do this, the water that has condensed on the electrical parts inside will cause problems. It is mentioned in documentation of the new televisions that if it is cold, you should bring the television into the room but only switch it on after it has adopted the room temperature. The same holds for all equipment, new or old.

 

PACKED: Should the equipment also be protected from dust?

Marc Vandeputte: Yes. To protect a device from dust, you could put it in a plastic bag possibly with silica gel bags for humidity protection. Dust is bad for the airflow and for the cooling of the equipment. It is important for the airflow inside the television to have all the ventilation and cooling slots free, so that air can get in and keep the delta T as low as possible. In devices where there is no natural airflow, for instance in a laptop, the manufacturer will build in a fan to suck in cold air and blow it over the motherboard. When you get a device, you should open it, remove all the dust and clean it. Removing dust is also important for CRT monitors and televisions because there is an area on the CRT tube where the EHT wire is connected that is not coated. The rest of the tube is covered with a conducting black coating made of graphite. The non-coated area must be free of dust, moisture and humidity. If there is a lot of dirt, there will be a flash-over, as this area does not work as total insulator. It involves high tension, so you must be sure that there are no conductive parts in this insulated area or on the EHT wire as it carries 30kV. If there is too much dirt creating a conductive area, this can cause a spark or an arc just like a lightning bolt. Often when you switch on an old television, you will hear a static charge and discharge, just like when you take off a synthetic pullover. It is the EHT that is crackling. The more dirt attached, the more you will experience crackling. To prevent a flashover in any part, you must clean this area of the CRT. By cleaning this area you will reduce a lot of possible defects. However when cleaning the CRT tube, you should never use a tissue because of the graphite particles that you could gather in that area. You may also clean the EHT wire as it attracts a lot of charged particles because of the high tension. Mechanical moving parts are very sensitive to dust. It may cause unwanted friction in the gears.

 

 

PACKED: Any other things that shouldn't be done?

Marc Vandeputte: It can be dangerous to grease some parts of devices. A lot of plastics decompose within two or three days if they come into contact with oil. Never apply grease even on metal parts because it has a tendency to spread out and come into contact with plastic that will then break. One should never apply grease unless it is clear that everything is mechanical, like for instance in the big old tape recorders where almost everything is mechanical. A lot of plastic parts may not be greased with oil. There are specific liquids to be used with plastic in video recorders or tape decks in order to apply grease where necessary.

 

PACKED: A lot of artworks use monitors and other equipment that are built, for example, into a wooden sculpture. Could this be optimised?

Marc Vandeputte: Let’s imagine that a monitor is placed in a box. You have to keep in mind that hot air always has a tendency to go upwards. Which means that you must make ventilation openings in the box or cube. The diameter of these holes must at least be equal and preferably bigger than the thickness of the material of the box. Air wants to flow but not into openings that are too narrow. You must consider the thickness of the embodiment. The ventilation holes must also be placed at the bottom and at the top to allow for good circulation of the air. All televisions are designed to let the cooling air in at the bottom, and the hot air out at the top. If an artwork uses a CRT monitor upside down or on its back, then the cooling and the natural convection inside the television is ruined. The result is that the lifetime of the monitor will decrease. If you put a monitor or television upside down or on its back, you should apply forced cooling.

 

PACKED: A case study that is part of our research project is an installation from the Stedelijk Museum in Amsterdam made by Bert Schutter called ’Mill x Molen‘. The monitors are placed in rows at forty-five degrees and these rows form the shape of a mill.

Marc Vandeputte: An inclination of forty-five degrees is still acceptable. The monitors will still be cooled by natural convection. As long as it is not tilted to more than forty-five degrees in any direction then there shouldn't be any problem but if it's at ninety degrees or upside down the natural cooling will be ruined. Then forced cooling should be considered, which is not that easy to do. Imagine hanging a television up on a ceiling: the air cannot flow. The ceiling is already the hottest place in a room. Cold air comes from the bottom, so you need to have a chimney effect inside your device.

 

PACKED: The monitors in this work are also aligned, can this create a problem?

Marc Vandeputte: If they are in-line touching each other and if the room temperature does not go above 35°C, it should be OK.

 

 

PACKED: Can re-soldering poor solder joints be recommended as a preventive maintenance action?

Marc Vandeputte: Yes, all sensitive joints can be re-soldered proactively. They are one of the more common causes of failure.

 

PACKED: Are there any useful other preventive steps that can be taken?

Marc Vandeputte: Some equipment does contain batteries and one shouldn't forget about them. They can have a double function in the equipment: overcoming a mains dip or long periods of time with no voltage and keeping the memory settings. Most of the time the memory function in a device is there to keep presets like for instance a stored frequency. In an older television a battery often maintains the memory while the equipment is switched off. Batteries were used until 1987 in Philips televisions: the memory required a battery to keep it under voltage. Most of the time, there were Nickel-Cadmiums in PCBs that could maintain voltage for approximately one month. If one had switched off one's television for more than one month, then the television's memory was lost and one had to reprogram it. If they were of good quality, they could withstand two months and sometimes even longer, depending also on the current that was drawn from the battery by the circuits or on the quality of the battery itself. By putting a television onto standby mode the battery was kept completely charged. So one has to watch out for those batteries as well.

Today batteries are still used in other equipment like laptops where they maintain voltage for the BIOS, or in some FM radio tuners because it is more convenient. There are short batteries of 1,2V, and longer ones. The voltage increases each time by 1,2V; you have a version at 3,6V, 2,4V and 1,2V. They can all be bought on the Internet if one knows what shape they are. If you detect a battery inside, you can replace it with a brand new one and then you can switch off the device for a longer period of time without losing any information. Never consider that your system has a defect and that you have to throw it away, because it could simply be that a battery is flat.

 

PACKED: If elcaps need to be replaced, would you recommend replacing them all at once?

Marc Vandeputte: It depends. I have repaired many televisions during my life; I can’t remember the exact number. At a certain moment you start to notice the weak points of a television. You see a phenomenon in the picture and you can immediately tell if it comes from the frame deflection or the line deflection, or from the power supply itself. If a type, kind or brand of elcaps has been used and you notice that they are of a lesser quality, then you should replace them all as a preventive action, as well as to satisfy a customer…But replacing all elcaps at once can also be a waste of money because in some televisions only three elcaps will have to be replaced and twenty-five others of the same brand will never wear out. There is a reason for this. In certain circuits the voltage fluctuates between different values. By putting a resistor and an elcap at the entrance, the voltage will become stable. When the voltage fluctuates we call it a ripple current. The elcap will compensate for the amount of voltage swing, and deliver current when the voltage is low. The higher the ripple current, the sooner the elcap will go down. This is the reason why in some circuits where the ripple current is very low, the elcap will last longer than in circuits where the ripple current is very high. It is just like an engine: if you let it run at 2.000 rpm, it will last longer than when the same engine runs at 4.000 rpm.

 

PACKED: Are capacitors replaceable by others?

Marc Vandeputte: You should replace the elcaps by the original ones, in values as well as types. The brand is not important, but the type is crucial. Capacitors have different shapes: some have a tubular shape, some look really old-fashioned, etc. There is always a (Plus) + and a (Minus) – side, and there is always a capacity mentioned, for instance 100 microfarads and 25V. You cannot replace it with an elcap that has 100 microfarads and 16V because it will not withstand the tension. It means that the maximum applicable voltage is 25V and if you replace it with 100 microfarads but with 16V, it will explode. You may replace it with a 35V, but it is better to replace it with the same value.

 

PACKED: Is it possible to relate a defect in the picture to one of the components?

Marc Vandeputte: Yes, some defects are directly related to some specific components but one has to be an experienced technician to see this.

 

PACKED: Some museums have skilled technicians who know about televisions, monitors and/or video technology. But most of them are small museums that have no technicians, so they need to invent a different strategy.

Marc Vandeputte: By having no skilled technician they are taking risks. If, for example, they put a device into a situation for which it was not designed, it’s normal that the equipment will have problems. Museums should have a technician, or should invite someone to give them proper advice before the exhibition is installed.

If you want, for example, to hang a television set upside down with the screen facing the ceiling and the back of it to the ground, you should first of all ask a technician what precautions you should take to prevent damage. You should also ask how to make it stable to avoid it collapsing or falling. A television is not made to withstand its own weight when it is put on its back. It's made of plastic, and is often flexible. Although sometimes televisions can be really rigid and strong, they are not designed to lie on their back. You should ask how to install forced cooling. If you put the television upside down, the air won't be as it should, so you have to apply forced cooling. You can do it with a fan but if you put it at the front, the whole exhibition will be ruined by it. An inventive technician can put a fan in the right place to suck out the air or better distribute the air inside the television so that the hot air comes out and at least some components will be cooled.

 

PACKED: What about screen burn-in?

Marc Vandeputte: Still images should not be displayed permanently on plasma, CRT screens or LCD screens. Burn-in is the reason why a lot of broadcasters move their logo around the screen every half hour or two hours, and also make the logo as transparent as possible. Logos came in late; in the initial television world there were no logos. In some Philips televisions the picture is shifted regularly and the customer doesn’t see it. The image goes down a few steps; so in fact the picture moves. You alternately lose a bit of the picture on the top, on the bottom, the left or the right, to prevent burn-in.

 

PACKED: Is it good for the CRT tube to display a grey image after a long period of no-operation?

Marc Vandeputte: Yes. If you display a grey picture, you will not overload the tube or many of the electronics. They will be in a moderate mode. If you display a white picture, the EHT generator must work a lot; there is a lot of ripple current on the elcaps and on the three electron guns that produce the red, green and blue. To get the correct mixture and produce a white picture, they have to be charged a lot. Of course televisions are made to withstand such heavy charges, but for the picture tube's lifetime it is better to use a grey picture. It should not be a green, blue or red one, but a grey one, because a grey one will charge each pigment equally. If you display a red picture with low contrast you will force the red phosphors to give light while the blue and green ones are not activated.

 

PACKED: What is the current life cycle of a Philips product?

Marc Vandeputte: The maximum selling time for a typical Philips television set is one year or less, then new models are introduced. Of course the developing time is more. The spare parts for every product are available for at least seven years or more, it depends. We must predict which components will fail. If during the development phase we can predict that a component is weak, then we make it stronger or try to find a way for it to be less stressed. No component is applied outside its own specifications.

 

PACKED: What happens after seven years? When this period ends, do you keep the spare parts?

Marc Vandeputte: They are kept as long as possible at the Service Department.

 

PACKED: Is it a good idea to create a stock of components like power components and elcaps, or are they always more or less the same?

Marc Vandeputte: It’s difficult to predict what components will be available for a long time. Also it's difficult to predict what component will fail… You might end up with more parts then what will ever be required. But asking a technician who knows the equipment used in a museum what spares to be ordered can help a lot!

 

PACKED: Are the service manuals archived somewhere?

Marc Vandeputte: Yes. Some are here in Brugge and some are in Eindhoven, but everything that is designed here has its manual available here.

 

PACKED: Can a customer ask for them?

Marc Vandeputte: No, only Philips staff can ask for them. The production and distribution of service manuals is very expensive, and so they are printed in limited editions for professional service people only.

 

PACKED: They are not all digitised?

Marc Vandeputte: Many are produced in PDF format, and others for old televisions are scanned.

 

PACKED: Where can museums find a repair service if they want to get their old televisions repaired and if don’t have technicians who are familiar with electronics themselves?

Marc Vandeputte: You can always refer to Philips for Philips products to find the nearest authorised service centre. In former times Philips had a lot of repair centres, but nowadays they are subcontracted. There used to be a lot of people with extensive knowledge about old Philips televisions in such centres. The repair of televisions is a specialisation. I know a lot about older Philips televisions but I can't say the same for televisions of other brands.

 

PACKED: Where do you go to find this kind of information on the Internet?

Marc Vandeputte: You simply search on the Internet by typing in the type number of the equipment and you'll get a list of sites with info about it. I go on a Dutch forum for amateurs and professionals called circuitsonline.net. You can post any question there about the model number and the problem. It is a community that shares information and gives advice to others. Such information is available, of course, as long as the sites are maintained…

 

PACKED: This is also a way to record knowledge about equipment that is obsolete or soon to become so.

Marc Vandeputte: A lot of televisions and electronic equipment have become throwaway products and no one is interested in the knowledge related to them. Philips has ‘Circuit Descriptions’ in its Service Department which are available with the service documentation. As such the working of the applied circuits in the equipment and some service advice is available.

 

PACKED: Your concern for old televisions makes you some kind of a Philips archivist?

Marc Vandeputte: Yes, in a certain but very limited way…

 

 

Notes

 

• 1. DVB via Satellite
• 2. The delta T represents the temperature difference between the « off » and « on » condition.