The lcd needs ~7.5v with a min of 6.9v to work properly iirc. I was going to use the 7v mod, but am unsure how well that would work as my 12v rail is 11.67 and my 5v rail isnt perfect either... any ideas how to do this with only a simple circuit? I had this idea just now: 5v 12v--lcd-| #ground with the # representing a resistor of some value. the mains adaptor from the lcd was rated 3A, but only 1A is needed for the lcd (the adaptor is for powering the ps aswell)
THB when I did this for a friend all I did was put the adaptor in the PSU [ or around it ] and soldered it in parallel with the PSU's AC cord.
Can be, we havn't confirmed that yet. I could see how long it takes my new psu to die, its still under warranty... jk
Well I know 12-5 = 7v is not bad for psu's, the LCD is an inductive load I assume, becuase of the ccfl, does that mean I need to put ferrite things on the power cable? I have opened up my psu before - there is no room atall for a brick psu, or even just a pcb if I took the brick apart... Not going to risk breaking the lcd or a psu using 12-5v so can someone help me make a 7.5v regulator circuit for it please
if I got a lm7804 for 2A and then connected that as neg with 12v as +, thatd give me 8v, should work... where can i get a lm7804? hmm maplin dont have a 2A one... and a lm7808 would be better anyway, but they only do 1A versions :E could I use one of these? http://www.maplin.co.uk/products/module.asp?CartID=040507183159481&moduleno=2334&Products=1 edit - thatll cost too much, might try again with a lm317t, last time i couldnt get the one I had to work properly though Also if I used a lm317t to control a fan, using -12 to +5 for power, and the psu rated to 1a on -12v, anything I should do to protect the psu, and say the fan draws 0.5A, what will the lm317 take?
LM7808s in parallel, then. And don't forget about adequate heatsinking. I wouldn't trust a voltage divider for a dynamic load like even an LCD module.
Wont work, as you will then have the negative of the LCD at 5 volts compared to the shield of the VGA card, which will be at 0 volts, when you plug the monitor into the VGA card you will short out the 5v rail thru the LCD, composite cable, and VGA card, most likly smoking whichever cost you the most.
Thankyou I knew there would be a good reson, now I know The person that tryed this way smoked the power cable, but nothing else.. which is odd... Would i also need diodes and stuff to stop one lm7808 powering the other? if so what type? just normal ones? Would there be anything else I need for doing this? The lcd only takes 1A ( the ps one plug is 3A and the ps one uses 2A) but 2A would be safer I think? worth the extra effort?
