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Please help, i need to bypass the on off switch on my telefunken lcd tv

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warrenhunter

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Hi

I would like to bypass my on off switch on my lcd tv so that it will come on and stay on when the main power is switched on and will only turn off when the main power is turned off please help i am desperate
 
Having done something like this 30 years ago, the parts I used aren't available anymore. I had it a bit easier. I had an off button and an on button

Interfacing the button is probably easy. An LED power indicator is a plus.

Bet your is a push on/push off deal and the remote has the same.

Without some of these questions answered, it's hard to even suggest a solution.

Some systems have an OFF IR command as well as toggle IR commands, so IR is a possibility maybe.

You may need to know the state of the TV too.
 
thanks guys for your reply

ok the deal is i am using the tv as a monitor with a small pc unit to play movies. the main power is fed through the pc which then once powered up powers the tv. i have had no problem with this in the past as i would just bridge the power and grd pins on the board from the inverter to the key board. unfortunately they discontinued the model of tv that i was using. the new model (telefunken TLCD-19JA) has an external inverter so the pin slot that i used it no longer in use. the power button on the tv is a push on push off that has two leds red and blue. i have tried bridging it but it would then just loop the power up (like i was consistently resetting) i have narrowed it down to a grd pin and k7 pin but only works on a pulse and cant be bridged. i am still new to electronics so not to clued up on technical terms. I am desperate because it is a part time business of mine and i am running out of time to find a solution. thank you
 
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Assuming the set always powers up in standby, then you can use two simple 555 timers, one as a powerup timer (to give the set time to finish settling down), and the other to briefly short together the ON/OFF button.

I did this years ago (hence the 555's) to use camcorders as security cameras.
 
thank you both. Nigel would you if you can post or send me a diagram as i am still not too familier with the 555 pic. many thanks
 
thank you both. Nigel would you if you can post or send me a diagram as i am still not too familier with the 555 pic. many thanks

The 555 isn't a PIC, it's an ancient analogue timer chip - if I was doing it today I'd use a small 8 pin PIC instead.

I don't have the schematic I used, I'm not even sure I ever drew one - and it was probably 30 years ago?.

Assuming you can program PIC's? (if not use a PICAXE which is dead simple, and still cheap) then you just need to have a PIC pin feeding a transistor, which feeds a small relay - with the relay contacts wired across the switch.

Simply program the PIC to wait ten seconds or so after power up, and then set the I/O pin high for one second -after that set it low, and put the PIC in an endless loop.
 
I've just dug this out of my archives. I think this is probably similar to the circuit Nigel was reffering to.
 

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Pin 4 of the 555 is the enable pin - the best way to connect two together is to connect the output of the first to pin 3 of the second.
 
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