NotTaR of Television Sets : Problems with the IR remote receiver    
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Problems with the IR remote receiver

Although the hand unit is most likely to be the cause of any problems with the remote control, it is also possible for the IR receive module to fail or for power to it to be missing. Microcontroller problems as well can result in similar symptoms.

First confirm that the hand unit is putting out the correct code. If it is a programmable type, try re-entering the settings for your TV. Install a set of fresh batteries. Try a different remote if possible. Use an IR detector to verify IR emissions (see the section: Revival of dead or tired remote control units).

The IR receiver is often a self contained module connected to the rest of the TV's circuitry by 3 wires: Power (+12 V typical), Ground, and Signal Out.

The IR receiver module will be located directly behind the IR window. Test by confirming that DC power is present. A schematic will tell you exactly what it should be but figure on 6 to 12 V if you do not have one. If this is present and you have an oscilloscope, put is on the Signal Out. You should see the demodulated data stream corresponding to whatever key is pressed on the hand unit. It should be a logic level signal swinging between 0 and the supply or +5 volts.

If there is no power, then a bad cable connection or blown fusable resistor may be the cause. If there is correct power but no signal, a fault internal to the IR module is likely. The internal circuitry may be a combination of special ICs and discrete components. The Sams'' or service manual may or may not provide the details. There may be an adjustment for the carrier frequency but don't be tempted to touch this unless you have exhasuted other possibilities - and them mark it first!

If the signal is present, then there may be a problem in the microcontroller or other logic on the mainboard. This will require a schematic to proceed further.

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