remote control problem

[thefixer]

Hello every body,I have Thomson TV model 14MG10G.it has processor:TMP 47c1637n-RA34.tda8842.Eeprom24w04 1.the problem is even though remote control is ok it doesn't work i tried other remote controls but in vain.I also replace IR receiver of the set but in vain.... any one to help me with this.Thanks in advance.

[minnie]

If you replaced the IR sensor and it's still no go replace the micro.

[torbjorn]

Some Thomson TVs have a membrane keyboard for the local buttons on the front panel. It is common that switches of that keyboard get shorted, "stuck". In this case, the TV will not take commands from the remote.
Easiest way to check it is to disconnect the keyboard and see if the remote begins working.

Also, make sure that the micro's clock (crystal or ceramic resonator) is running at the correct frequency (check with scope and frequency counter).

Regarding the IR receiver, make sure that you get clean 0/5 V data on its output when trying the remote and that it doesn't put out garbage at no input.
Those IR receivers have an integrated bandpass filter that must match the remote's modulation frequency. Most types of receivers are available with a number of different center frequencies between, say, 30 kHz and 50 kHz , 38 kHz being the most common one.

A common problem today is that some modern low energi lamps or fluorescent tubes with high frequency ballasts happen to operate at the same frequency as the remote control, effectively blocking all communication.