GB2479222A

GB2479222A - Diagnostic Device for Testing a Television Set

Info

Publication number: GB2479222A
Application number: GB1018434A
Authority: GB
Inventors: Khidori Fawzi Ibrahim
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-04-01
Filing date: 2010-11-01
Publication date: 2011-10-05
Also published as: GB201005576D0; GB201018434D0

Abstract

A diagnostic device 10 for testing the power supply and main circuit board of a television set. The device utilises a standby (STB) voltage of the television set and comprises an indicator 8 that indicates whether the standby voltage is present and a connection 11 to the power supply to provide the activation signal when the standby voltage is present. The device may also provide further signals to further features of the television set such as an inverter or the sustain voltage. The device may be temporarily connected to the power board of the television set using a parallel connector such as a branched ribbon connector. Also disclosed is a method for testing a component of a television set utilising the diagnostic device.

Description

TESTING DEVICE

Background to the Invention

[0001] This invention relates to a device for assisting in testing components of an electronic apparatus such as a television set.

[0002] In modern LCD (liquid crystal display) and plasma television sets, the main board (sometimes called the small signal board -SSB) or, in the case of a plasma television, the logic board, controls the operation of the whole system.

The power supply and the inverter will turn on only upon receiving control signals from the main board. In the case of a plasma set, the sustain voltage Vs and the fan (where there is one) are also turned on by a control signal from the main board. The Standby voltage is the only voltage that the power supply generates without prompting from the main board; it is present as soon as the TV is connected to the mains supply. All other voltages are generated only following a control signal from the main board/logic board.

[0003] Conventional testing of LCD and plasma television sets takes place with the set intact, i.e. with all the boards present and connected to each other.

It is difficult to identify a faulty board from the symptoms because different faults may produce the very same symptoms. For instance, a fault in the main board would cause the power supply not to function and with it the inverter to fail to operate. The same thing would happen if the power supply was faulty.

[0004] In conventional testing, the power supply cannot be tested in isolation from the main board.

Summary of the Invention

[0005] With these problems in mind, the present invention provides a diagnostic device for providing an activation signal to activate a power supply of a television set, the device being adapted to utilise a standby voltage of the television set and comprising: an indicator arranged to indicate whether the standby (STB) voltage is present; and a connection to the power supply to provide the activation signal when the STB voltage is present.

[0006] Such use of the STB voltage means the device can be a passive device.

The device may be arranged for at least temporary connection to a power board of the television set. Such a connection can obtain the STB voltage and/or provide the activation signal to the power supply.

[0007] In one embodiment, the device is arranged to simulate the presence of a circuit board of a television set, which circuit board usually provides the activation signal to the power supply, the device being adapted for connection to the power supply when the power supply is disconnected from the circuit board, and the device being arranged to provide said activation signal such that functioning of the power supply can be tested without being connected to the circuit board. This embodiment may include a parallel connector for connecting the device to an existing connector on the power board. "Parallel connector" is used in this specification to mean a cable such as a ribbon cable, a header for a cable already existing in the television set, or a direct rigid connector or the like.

[0008] For additional testing of the main board, another embodiment includes at least one parallel connector that is for connecting a power board of the television set to the device and simultaneously to a main board of the set. The parallel connector may be a branched ribbon cable.

[0009] Yet another embodiment of the device includes a first parallel connector for connecting the device to the power supply and a second parallel connector for connecting the device to a main board of the set. The first and second parallel connectors can be comprised in an adapter connected to the device.

[0010] The device may include at least one switch for connecting the STB voltage to the power supply as the activation signal. It may also include at least one test indicator for indicating that the activation signal is being provided to the power supply.

[00111 If the device is adapted for assisting testing of at least one component of a liquid crystal display (LCD) television set, the at least one component may comprise an inverter to which the device is arranged for indirect connection. In this regard, the power board may be an integrated power board carrying the inverter as well as the power supply.

[00121 If the device is adapted for assisting testing of at least one component of a plasma television set, the at least one component may comprise a sustain voltage supply and/or a fan.

[0013] The present invention also provides a method for testing at least one component of a television set, the at least one component requiring a control signal for activation thereof, the method comprising providing a device as defined above, connecting the device to the at least one component, and monitoring the functioning of the at least one component.

[0014] The method may include a preliminary step of disconnecting the at least one component from a circuit board of the television set. The at least one component may be in situ in the television set or removed therefrom.

Brief Description of the Drawing

[0015] The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: [00161 Figure 1 schematically shows a device according to an embodiment of the invention; [0017] Figure 2 is a circuit diagram of an embodiment of the invention for use with an LCD television set; [0018] Figure 3 is a schematic diagram showing components of an LCD television set; [0019] Figure 4 schematically shows use of the device with an LCD television set; [0020] Figure 5 schematically shows use of the device to test a power supply removed from a television set; [0021] Figure 6 is a circuit diagram of an embodiment of the invention for use with a plasma television set; [0022] Figure 7 schematically shows a branched cable embodiment of the invention; and [0023] Figure 8 schematically shows an optional adapter board; and [0024] Figure 9 is an exemplary circuit diagram of the adapter board.

Detailed Description of Particular Embodiments

[0025] Figure 1 shows a device comprising a packaged simulator board 1 and an adapter cable 2 being a flat parallel cable. A first plug 3 at one end of the cable plugs into a keyed header board 4 on the simulator board 1. A second plug 5 at the other end of the cable 2 is of a kind depending of the make of the television set to be tested. More than one cable 2 with different plugs 5 may be supplied with the invention.

[0026] Figure 2 shows the circuitry of the simulator board 1. An STB circuit 6 comprises a pushbutton switch 7, an STB LED 8, and a resistor 9 connected in series to a ground rail 10. A power supply test circuit 11 comprises a power supply LED 12 and a resistor 13, connected in series to the ground rail 10. A power supply test switch 14 is arranged to connect the STB circuit 6 to the power supply test circuit 11. An inverter test circuit 15 comprises an inverter LED 16 and a resistor 17, again connected in series to the ground rail 10. An inverter test switch 18 is arranged to connect the power supply test circuit to the inverter test circuit. Each of the circuits 6, 11, 15 and the ground rail 10 terminate at the header board 4.

[0027] Figure 3 schematically shows components of an LCD television set, namely an inverter 19, a power board 20 and a main board 21. The inverter and power board are connected by a cable 22 and the power board 20 and main board 21 are connected by at least one further cable 23.

10028] The invention can be used in testing a television set in its normal location without the conventional requirement to lay the set flat on a cushioned surface. With a housing of the set opened, the cable(s) 23 is/are disconnected from the header(s) of the power board 20, and the plug 5 of the device of the invention is connected to the header(s) of the power board instead, as shown in Figure 4.

[0029] The pushbutton switch 7 is then pressed. If the STB voltage is being generated by the power supply of the power board 20, the LED 8 lights. Next the power supply test switch 14 is closed, This connects the STB voltage to a "Power Supply ON" terminal of the power board 20 that, in normal use, receives an activation signal from the main board 21. The power supply LED 12 lights to show the activation signal is supplied from the simulator board 1.

A voltmeter can then be applied at one or more outputs of the power board 20 to test the functioning of the power supply.

[0030] In order to test the inverter 19, the inverter test switch 18 is also closed.

This connects the STB voltage to an "Inverter ON" terminal of the power board 20 that, in normal use, receives an activation signal from the main board 21, which powers up the inverter 19. The inverter LED 16 lights to show this activation signal is being supplied from the simulator board 1. If the inverter 19 is functioning illumination of the set's backlight will be observed.

[00311 The device can also be used with a power board that has been removed from a set and taken to another location, as shown in Figure 5. The device is connected to the power board 20, and the presence of the STB voltage and functioning of the power supply are tested in the manner described above.

The inverter board 19 can also be removed from the set and tested with the power board "off site" in this and other embodiments of the invention.

[0032] Figure 6 shows an embodiment of the invention for use with a plasma television set. An STB circuit 6 of a simulator board comprises a pushbutton switch 7, an STB LED 8, and a resistor 9 connected in series to a ground rail 10. A power supply test circuit 11 comprises a power supply LED 12 and a resistor 13, connected in series to the ground rail 10. A power supply test switch 14 is arranged to connect the STB circuit 6 to the power supply test circuit 11. A sustain voltage test circuit 24 comprises a sustain voltage LED and a resistor 26, again connected in series to the ground rail 10. A sustain voltage test switch 27 is arranged to connect the power supply test circuit to the sustain voltage test circuit. A fan test circuit 28 comprises a fan LED 29 and a resistor 30, again connected in series to the ground rail 10. A fan test switch 31 is arranged to connect the sustain voltage test circuit to the fan test circuit. Each of the circuits 6, 11, 24, 28 and the ground rail 10 terminate at the header board of the simulator board.

[0033] The device of this embodiment simulates the logic board of a plasma set. It is used in testing the STB voltage and the functioning of the power supply, sustain voltage (Vs) and fan of the set by connecting it to the power board and closing the switches in order in a manner which will be apparent from the description of use of the first embodiment.

[0034] In a television set, the DC supplies produced by the power supply and sent to the main board 21 are not used directly. They pass through regulators and other filtering circuits, generally on the main board, before they are used to power the various processing chips, amplifiers etc. on the main board.

Figure 7 shows an embodiment in which the circuits of the simulator board 1 are connected to the power board 20 in a similar manner to that described above, but by means of a branched cable 35. Here, the main board 21 is also connected to the power board 20, retaining the DC connections to the power supply. When the power supply is made to turn on by the signals from the simulator, DC voltages are generated by the power supply which the main board will receive in the normal way. In the absence of a defect the main board will thus function normally. This will allow the DC distribution within the main board as well as other functions to be tested. If there is a fault or open circuit it can thus be detected.

[0035] If the branching of the cable 35 occurs at the power board 20, there are effectively two cables rather than a branched cable.

[0036] Figures 8 and 9 schematically show an optional adapter board 40 for connecting the simulator board 1, power board 20 and main board 21. The connection to the simulator board 1 in this example is direct via a 15-w D-connector 42 with no cable involved. One of the connections from the adapter board 40 to the power board 20 and main board 21 is via the cable used by the set to interconnect the boards 20, 21. In a variant of this embodiment, not shown, the simulator board 1 is modified to include headers for connection to both the power board and the main board. This embodiment again reconnects all DC connections between the power board 20 and the main board 21 to allow testing of the latter.

[0037J Figures 7, 8 and 9 show use of the respective devices within the set but it is possible to remove both the main board and power board from the set and test them using the simulator board 1 and the branched cable 35 or the adapter board 40 and cables. It is envisaged that devices of these embodiments are dedicated to particular makes, models or groups of television set, as they address the main board, whilst the embodiments of Figures 1 to 6 can be used with a very large number of different models.

[0038] The device of the invention does not require a battery or mains connection. It provides a self-contained passive network enabling the control signals that would normally be generated by the main board or logic board, by connecting the standby voltage provided by the power supply of the set.

[0039] When the switches are operated in sequence, a faulty board will be identified instantly. The time taken to identify a faulty board is reduced by 50 to 80%.

[0040] Modifications which do not depart from the scope of the claims will be apparent to the skilled reader. For example, the cable 2 could be omitted, and the original cable 23 of the television set used instead. The simulator board 1 could then be provided with more than one header for use with different sets.

[0041] The invention can be used to test television sets in which the power supply and inverter are arranged on a single board called an Integrated Power board. References in the above description to a power board should be understood to include an Integrated Power board.

[0042] A modified version of the simulator board 1 includes one or more additional LEDs or other indicators for indicating the presence of one or more voltages produced by the power supply, other than the SIB voltage.

Claims

CLAIMS1. A diagnostic device for providing an activation signal to activate a power supply of a television set, the device being adapted to utilise a standby voltage of the television set and comprising: an indicator arranged to indicate whether the standby (STB) voltage is present; and a connection to the power supply to provide the activation signal when the STB voltage is present.
2. A device according to claim 1, arranged for at least temporary connection to a power board of the television set.
3. A device according to claim 2, wherein said connection obtains the STB voltage.
4. A device according to claim 2 or 3, wherein said connection provides the activation signal to the power supply.
5. A device according to any preceding claim, arranged to simulate the Q presence of a circuit board of a television set, which circuit board usually Q provides the activation signal to the power supply, the device being adapted for connection to the power supply when the power supply is disconnected from the circuit board, and the device being arranged to provide said activation signal such that functioning of the power supply can be tested without being connected to the circuit board.
6. A device according to claim 5, including a parallel connector for connecting the device to an existing connector on the power board.
7. A device according to any preceding claim, including at least one parallel connector for connecting a power board of the television set to the device and simultaneously to a main board of the set.
8. A device according to claim 7, wherein the parallel connector for connecting a power board of the television set to the device and simultaneously to a main board of the set comprises a branched ribbon cable.
9. A device according to any preceding claim, including a first parallel connector for connecting the device to the power supply and a second parallel connector for connecting the device to a main board of the set.
10. A device according to claim 9, wherein the first and second parallel connectors are comprised in an adapter connected to the device.
11. A device according to any preceding claim, including at least one switch for connecting the STB voltage to the power supply as the activation signal.
12. A device according to any preceding claim, including at least one test indicator for indicating that the activation signal is being provided to the power supply.
13. A device according to any preceding claim, wherein the at least one component comprises an inverter to which the device is arranged for indirect connection.

Q
14. A device according to claim 13, for use with an integrated power board carrying the inverter as well as the power supply.
15. A device according to any one of claims 1 to 12, wherein the at least one component comprises a sustain voltage supply and/or a fan.
16. A diagnostic device for providing an activation signal to activate a power supply of a television set, substantially as described herein with reference to Figures 1, 2, 4 and 5, or Figure 6, or Figure 7, or Figures 8 and 9 of the accompanying drawings.
17. A method for testing at least one component of a television set, the at least one component requiring a control signal for activation thereof, the method comprising providing a device according to any preceding claim, connecting the device to the at least one component, and monitoring the functioning of the at least one component.
18. A method according to claim 17, including a preliminary step of disconnecting the at least one component from a circuit board of the television set.
19. A method according to claim 17 or 18, wherein the at least one component is in situ in the television set.
20. A method according to claim 17 or 18, wherein the at least one component is removed from the television set. (\J