7805 reg

snow · Post by **snow** » Tue May 02, 2006 6:05 pm

is it possible to fry a 7805 regulator?? i installed a led mod on my psone screen and it worked fine (this was over a year ago) i just recently started working on my snesp again and i went to try the screen and the leds won't even light up, they reg is getting 7.5v and i have a 10 ohm resistor in between and i tried rewiring the leds and i still get nothing. i ran the power off of the screen at first and when that didnt' work i wired it to a spare 7805 i had laying around and it worked like twice and then it stopped again. i really need help! thanks

Post by **Skyone** » Tue May 02, 2006 6:09 pm

Yes, it is possible to fry a 7805. If you put in more than 25v/32v or if you are drawing out over 1A/1.5A out of the regulator, then it will fry.

I'm not sure about all the other problems, it sounds like a grounding problem though.

Post by **CronoTriggerfan** » Tue May 02, 2006 6:11 pm

Well, a 10-ohm resistor is too weak. This happened to me. Although for me, the mod worked for a while before the resistors blew and the LED's stopped...anyways, try wiring a 22-ohm resistor or two 10-ohm resistors in a series. And like Sky said, check your grounds. That's probably what's up. In either situation, you should get a more powerful resistor(s) installed. Good luck.

CTFan

snow · Post by **snow** » Tue May 02, 2006 6:14 pm

i have never input more than 7.5 volts into the reg, i have only ever have the resistor and leds hooked up to the reg also so i don't know whats wrong. i have replaced the resistor as well just in case but that didn't fix it. i was working on it about a week ago i the leds would flash on and off if i pressed down on the corner of the screen so i thought it was a loose connection so i rewired because i couldn't find it. if the leads off of the leds touch the metal casing on the psone screen could that be a problem? i may need ot tear it apart again. also could it be that the leds are fried because they shorted out or something??? thanks. i will check for grounding errors

snow · Post by **snow** » Tue May 02, 2006 6:18 pm

just tried adding another resistor and still nothing. just a quick question...i don't remeber if resistors are directional or if it matters. i seem to remeber that they aren't but i could be wrong. thanks

snow · Post by **snow** » Tue May 02, 2006 6:23 pm

sorry for the double post and now the triple...lol
i fixed my problem, there was a tiny peice of solder coming from a positive lead and was touching a ground...thanks for the help.