NORDMENDE SPECTRA SK2-COLOR TP8732 YEAR 1976.

A truly amazing example of compactness is this tellye.

The NORDMENDE SPECTRA SK2-COLOR TP8732 is a compact television with 22 inches color screen with ultrasonic remote and (ITT) VST Channel search tuning for 16 programs.
Where such apparatus as television receivers are to be controlled from a viewer location as to channel, volume, brightness, etc., the remote control systems usually are made up of a hand held transmitter which transmits an ultrasonic signal to a receiver connected to or built within the television receiver. The depression of buttons on the transmitter causes a variety of signals or signal frequencies to be transmitted, whereby channel change, volume change, etc. is responsively obtained.
However such systems have individually suffered from one or more problems, such as inability to have direct access to the desired channel, slow access, insufficient noise immunity making it often possible to operate the system with the jingling of a key chain or an ultrasonic sound originating from a dishwasher etc., unreliable control due to the absence of means to detect and suppress transmission errors resulting from echoes, interfering signal sources, etc. Also some control systems are not suitable for continuous analog commands such as volume, brightness, etc. Existing systems also often require the need for bandpass filters and accurate crystal oscillators which make them costly. Many systems are not very suitable for integration into custom integrated circuits.
The present invention provides a remote control system whereby the nature of the remote control signal allows utmost reliability of control. The remote control receiver will be found to be virtually immune to echoes and ambient ultrasonic noises, and therefore will not produce a false response in the presence of echoes and ultrasonic interfering signals. A variety of kinds of commands can be provided, and with the preferred embodiment disclosed, up to ninety-nine channels in a television receiver can be instantaneously selected, without the requirement for sequentially stepping through each channel. Volume can be varied or muted, tint or brightness controlled, etc.
The above advantages are obtained by the transmission of a unique type of two tone coded signal which advantageously contains information defining start-up transmitted data, type of command (i.e. channel select identification or miscellaneous command such as volume), information permitting reconstruction of clock and identification of end of data. The two tones are transmitted sequentially. The second tone is transmitted to provide masking of echoes produced by the first tone and to mask noises that may be present in the operating environment of the system.
Since the two tones may be close together in frequency, it is possible to operate the remote control system in conjunction with high sensitivity resonant type microphones, thereby achieving high sensitivity together with high noise immunity. This also eliminates the need for input bandpass amplifiers.
The inventive receiver is thus rendered immune from operation by extraneous noise further by the provision of received data error checking circuitry for the timing of input pulses, etc., and for rejecting the data if an error is detected. The receiver also has provision for operation of continuous analog circuits in a television set, such as brightness, volume and tint controls, etc. Since echoes are masked out in the present system, data transmission can occur much more rapidly than in prior systems, as the receiver does not have to wait until echoes die out between transmission of bits for identification of data pulses.
Since all that is frequency dependent is the detection of signal above or below a predetermined reference frequency, accurate crystals for timing and reference frequency generation are not needed. The receiver is virtually entirely digital logic, making it suitable for monolithic integration with a minimum of external components. CMOS integrated circuit logic is preferred, minimizing power supply requirements.
In the preferred embodiment, two digits are transmitted separately and the second must be received within a given time interval, or the first number is disregarded. This method eliminates the need for a clear key as normally present on calculators.
The output of the receiver is a binary or BCD signal which can be used by known means to control the frequency of a selected channel, or to perform other functions such as variation of volume, control of brightness, tint, etc. in a television set.
It should also be understood that the use of this invention is not intended to be restricted to a television set, but can be utilized for the control of a large variety of other kinds of apparatus, e.g. door locks, household appliances, radio receivers, production machinery, etc. While the description below will be directed to a wireless ultrasonic transmitter-receiver system, it should be understood that a wired system, a radio control system, etc. could be used in the alternative.
The advantages of the invention are obtained by the provision of a system including means for receiving a transmitted signal comprising a pulse envelope modulated continuous wave ultrasonic signal at a first predetermined frequency, each pulse being immediately followed by a continuous wave ultrasonic signal at a second predetermined frequency which has amplitude such as to mask echoes of the first predetermined frequency at the receiving means, the pulses being representative of a sequence of binary bits, means to determine whether the received signal is above or below the frequency of a reference frequency, means for recognizing a change in input frequency with respect to the reference frequency, and means for counting said changes, determining the value of the binary bits, and providing a parallel coded signal representative of said value.

The power button features the child lock key, to block the power up without the "KEY" inserted in it.

This model series was introducing in 1976 the SK2 series which was standing for "System Kalt"
named as Cool system referring to low chassis temperature.
Was more related to the RGB OUTPUT amplifiers than the line / horizontal output wich is realized with THYRISTORS and for that it runs warm as any Thyristor line output stage.

(The only with THYRISTORS Horizontal Deflection stages running almost really cool was that in GRUNDIG GSC600 AND GRUNDIG GSC700 CHASSIS which you can see Here)

- Horizontal Beam Deflection  and high voltage generating circuits realized with Thyristors circuits.
       Numerous circuit designs for completely transistorized television receivers either have been incorporated in commercially available receivers or have been described in detail in various technical publications. One of the most troublesome areas in such transistor receivers, from the point of View of reliability and economy, lies in the horizontal deflection circuits.
       As an attempt to avoid the voltage and current limitations of transistor deflection circuits, a number of circuits have been proposed utilizing the silicon controlled rectifier (SCR), a semiconductor device capable of handling substantially higher currents and voltages than transistors.
       The circuit utilizes two bi-directionally conductive switching means which serve respectively as trace and commutating switches. Particularly, each of the switching means comprises the parallel combination of a silicon controlled rectifier (SCR) and a diode. The commutating switch is triggered on shortly before the desired beginning of retrace and, in conjunction with a resonant commutating circuit having an inductor and two capacitors, serves to turn off the trace switch to initiate retrace. The commutating circuit is also arranged to turn oft the commutating SCR before the end of retrace. 

The set is build with a Modular chassis design because as modern television receivers become more complex the problem of repairing the receiver becomes more difficult. As the number of components used in the television receiver increases the susceptibility to breakdown increases and it becomes more difficult to replace defective components as they are more closely spaced. The problem has become even more complicated with the increasing number of color television receivers in use. A color television receiver has a larger number of circuits of a higher degree of complexity than the black and white receiver and further a more highly trained serviceman is required to properly service the color television receiver.
Fortunately for the service problem to date, most failures occur in the vacuum tubes used in the television receivers. A faulty or inoperative vacuum tube is relatively easy to find and replace. However, where the television receiver malfunction is caused by the failure of other components, such as resistors, capacitors or inductors, it is harder to isolate the defective component and a higher degree of skill on the part of the serviceman is required.
Even with the great majority of the color television receiver malfunctions being of the "easy to find and repair" type proper servicing of color sets has been difficult to obtain due to the shortage of trained serviceman.
At the present time advances in the state of the semiconductor art have led to the increasing use of transistors in color television receivers. The receiver described in this application has only two tubes, the picture tube and the high voltage rectifier tube, all the other active components in the receiver being semiconductors.
One important characteristic of a semiconductor device is its extreme reliability in comparison with the vacuum tube. The number of transistor and integrated circuit failures in the television receiver will be very low in comparison with the failures of other components, the reverse of what is true in present day color television receivers. Thus most failures in future television receivers will be of the hard to service type and will require more highly qualified servicemen.
The primary symptoms of a television receiver malfunction are shown on the picture tube of the television receiver while the components causing the malfunction are located within the cabinet. Also many adjustments to the receiver require the serviceman to observe the screen. Thus the serviceman must use unsatisfactory mirror arrangements to remove the electronic chassis from the cabinet, usually a very difficult task. Further many components are "buried" in a maze of circuitry and other components so that they are difficult to remove and replace without damage to other components in the receiver.
Repairing a modern color television receiver often requires that the receiver be removed from the home and carried to a repair shop where it may remain for many weeks. This is an expensive undertaking since most receivers are bulky and heavy enough to require at least two persons to carry them. Further, two trips must be made to the home, one to pick up the receiver and one to deliver it. For these reasons, the cost of maintaining the color television receiver in operating condition often exceeds the initial cost of the receiver and is an important factor in determining whether a receiver will be purchased.
Therefore, the object of this invention is to provide a transistorized color television receiver in which the main electronic chassis is easily accessible for maintenance and adjustment. Another object of this invention is to provide a transistorized color television receiver in which the electronic circuits are divided into a plurality of modules with the modules easily removable for service and maintenance. The main electronic chassis is slidably mounted within the cabinet so that it may be withdrawn, in the same manner as a drawer, to expose the electronic circuitry therein for maintenance and adjustment from the rear closure panel after easy removal. Another aspect is the capability to be serviced at eventually the home of the owner.

It was even introducing first time the use of the 20AX CRT TUBE (PHILIPS) in models from 26 to 22 Inches but in few it was replaced by the VIDEOCOLOR P.I.L.

The new tube, to be known as the 20AX, has been developed by PHILIPS in conjunction with the parent Philips / Mullard organisation and will be produced by several Philips subsidiary companies on the Continent as well as by PHILIPS in the UK. PHILIPS envisage quantity production of the tube by 1976, mainly for export at first, with large-scale production for UK set - makers starting in 1977. The tube has been developed as "probably the final phase in the design of the 110° shadowmask tube". Its main features are the use of three guns mounted horizontally in line, the use of a shadow - mask with slots instead of circular holes, and a screen with the phosphors deposited in vertical stripes instead of as a pattern of dot triads. It seems therefore that the days of the present delta gun shadowmask tube are now numbered, though considerable production will have to continue for many years to provide replacement tubes for the millions of colour sets already in use. So far as the viewer is concerned however it is important to appreciate the time scale involved (see above) and the reasons for the development of the new tube. There is nothing wrong with the type of shadow - mask tube we have known since the beginning of colour TV: it is able to provide superb pictures. But in its 110° form it does require rather a lot of scan/convergence correction circuitry. If this can be reduced by means of an alternative approach

as with the 20AX tube  considerable benefits in set production and servicing will be obtained. This has been the aim behind the development of the new tube, and the demonstration tube we have seen operating with its associated deflection yoke and circuitry gave a picture every bit as good as we have come to expect from the present "conventional" approach to colour tube design. There are now four colour tubes with in -line guns, the Sony Trinitron (the first to come along), the RCA /Mazda PIL tube, the Toshiba RIS tube and now the PHILIPS 20AX. It is interesting to compare them. The Trinitron is a 90° narrow neck (29mm) tube. It differs from the others in using an aperture grill (slits from top to bottom) instead of a mask behind the screen to shadow the beams and a tube face which is substantially flat in the vertical plane. On the domestic market it is used exclusively in Sony sets and certainly represented a break through in simplifying the convergence circuitry and setting up adjustments required. The Toshiba RIS (rectangular flare, in-line guns, slotted shadowmask) tube has now turned up in the UK in the recently introduced 18in. Sharp Model C1831H. Its most distinctive feature is the rectangu- lar instead of conical tube flare and the rectangular semi -toroidal scanning yoke which is used with this. It is a 110° thick neck (36mm) tube. The convergence arrangements are fairly simple. The most interesting comparisons however are between the PI tube and the 20AX. The first is a 90° tube of the narrow neck variety and features a toroidal yoke which is cemented to the tube- thus if either is faulty the entire tube/yoke assembly must be replaced. The great advantage is that no dynamic convergence adjustments or circuitry are required. It is at present limited to sizes up to 20in. and the designers say that it is not intended as a successor to the standard shadowmask tube above this size. Its depth compares with 110° tubes because of the simplified gun structure used. The PHILIPS 20AX tube differs from it in several respects. First it is basically a 110° tube which can be produced in a whole range of sizes production of 18, 22 and 26in. versions is proposed so that set  makers can use it with a single chassis for models of various sizes. Secondly it uses saddlewound deflection coils which are separate from though accurately aligned with the tube. And thirdly it is a thick neck tube. Unlike the PI tube in which all the gun electrodes except the cathodes are common to all guns the electrodes of each gun in the 20AX are separately available at the base. This means that in addition to RGB drive to the cathodes the grids are available for blanking and beam limiting and the first anodes for background control setting in the normal manner. In fact PHILIPS emphasised that the new tube is entirely compatible with existing colour set techniques  though the whole convergence system is greatly simplified. The basic idea behind these in line gun, slotted mask tubes is that by mounting the guns horizontally in line the convergence errors are confined to the horizontal plane and by applying an astigmatic deflection field these errors are cancelled. This means that a fair amount of cunning in the design of the deflection yoke is required. A saddlewound yoke is more efficient than a toroidal yoke since the deflection fields are totally enclosed.

 In comparison to current 110° PHILIPS tubes the 20AX requires much the same horizontal deflection power but about twice the vertical deflection power (which can be obtained without trouble from modern semiconductor devices). The use of a separate yoke with a tube of this type means that some dynamic convergence controls are still necessary, in order to match the assemblies. PHILIPS refer to these as "tolerance adjustments" rather than "dynamic convergence controls". About seven are required at present though further work is being done on this and by the time sets with the new tube appear we can expect some reduction. A single pincushion transductor is required instead of the two needed with 110° shadowmask tubes of the present variety. In comparison the PIL  tube requires no dynamic convergence adjustments, only some simple tube neck magnets for static setting up. It is a little less efficient however because of the type of yoke employed. Whatever else happens there is no doubt that the vast majority of colour tubes fitted to TVC sets come 1977 will be of the in line gun, slotted mask, vertical phosphor stripe variety. Two further points made by PHILIPS at their demonstration : first, this type of tube requires less degaussing so that there are worthwhile savings in the amount of copper required for the degaussing coils: secondly their new tube, and in fact all PHILIPS monochrome tubes and shortly their colour tubes as well, will incorporate "instant on" guns which come into operation about  five seconds after the set is switched on instead of the 30 seconds or more taken by present tubes. This instant on feature is based on a new heater/cathode assembly in which the use of mica insulators has been avoided. 

Meanwhile we understand that in addition to RCA and, in the UK, Mazda, ITT and Videocolor SA are to produce PIL tubes. Whilst congratulations all round was appropriate on the successful development of these  tubes it does seem a pity that was about to enter for the first time an era of non compatible colour c.r.t.s.

(To see the Internal Chassis Just click on Older Post Button on bottom page, that's simple !)




Nordmende was a manufacturer of entertainment electronics based in Bremen, Germany.
The original company, Radio H. Mende & Co, was founded in 1923 by Otto Hermann Mende (1885-1940) in Dresden. Following the destruction of the plant during the bombing raids in 1945, Martin Mende (the founder's son) created a new company in Bremen in 1947, in a former Focke-Wulf plant, under the name North German Mende Broadcast GmbH. The name was subsequently changed to Nordmende: subsequently the company became one of the prominent German manufacturers of radios, televisions, tape recorders and record players in the 1950s and 1960s.
In the 1970s, Nordmende televisions were renowned for their innovative chassis, and for the rigorous testing and quality control of their finished products. Both created high costs, however, which soon proved a competitive disadvantage when the price of colour televisions began to plunge.
In 1969, Mende's sons took over the company, and in 1977 a majority shareholding was sold to the French Thomson Brandt company and the chassis remains the original NordMende until CHASSIS F9. The following year, the family sold their remaining shares to Thomson. In the 1980s, the factories in Bremen were closed, Nordmende becoming purely a Thomson trademark (Starting from chassis F10 F11 they're all THOMSON).








In the 1990s, the name Nordmende was used with decreasing frequency, and it eventually disappeared in favour of the Thomson name. In 2005 Videocon Group acquired all cathode ray tube activities from Thomson. This led to the creation of VDC Technologies, which manufactures TV sets using the Nordmende brand under licence from Thomson.
The Nordmende brand name was relaunched in Ireland in September 2008 by the KAL Group. Although Nordmende was well known for its televisions throughout Ireland during the 1970s and 1980s, the company bought the rights to the name and launched a range of white goods including fridges, freezers, washing machines, and dishwashers, alongside a revamped range of flat-screen TVs and stereos.

Weblinks:

 Commons: Nordmende – Sammlung von Bildern, Videos und Audiodateien
Tote Marke NORDMENDE – Verblasster Stolz. Artikel im Manager-Magazin
Ein neues Programm. Artikel in der Zeit
Fernseher: Inder produzieren neue Nordmende. Artikel bei itespresso.de
Videocon produziert Plasmaschirme für Nordmende. Artikel im pressetext.de

Einzelnachweise

Spectra Color Studio und Spectra SK2 Color de Luxe Studio auf radiomuseum.org
Marke Nordmende mit Digital- und Internetradios zurück, teltarif.de, Artikel vom 2. September 2017.


Company profile. Phillar, archiviert vom Original am 6. März 2008; abgerufen am 26. April 2013 (englisch).


Broschüre – Sprachmanager24. Abgerufen am 5. Januar 2015.