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
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
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.
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.