Video instructions and help with filling out and completing Are Form 8815 Affordable

Instructions and Help about Are Form 8815 Affordable

All right so today I want to talk about a basic topic when it comes to troubleshooting some of these circuits and this is something that comes in handy if you haven't known good around so this is a machine that has no backlight on the screen and it's something I've mentioned in a couple of prior videos but it's not something that has its own dedicated video and it should because this is a really this basic concept in electronics and it's something that's gonna help you along in your troubleshooting so if let's say that we have a circuit that is it that it's supposed to create a certain amount of brightness for the screen a certain amount of voltage for the screen and it knows what the load of the screen is going to be let's say if we want to create 27 volts now the output of a circuit can actually give you an idea of what's going on with it so here I'm gonna measure backlight output at a specific point in the circuit and I get thirty nine point six volts now this is where again one of the things that really helps me is having this whole pile of stuff that works well some of it works where I can just go okay what's that supposed to be and I measure it and I have an answer and it kind of helps me with my thought process so I'm so I know that I'm supporting machine when brightness is all the way up I get 27 volts so why is my voltage 39.6 that means I should have more light right now what a lot of people will say is oh the screen must be broken or that the light got blown out because the board was delivering too much voltage that's what I hear from a lot of new students and a lot of people when I ask them this question rhetorically the real issue here is that there is no path to the screen so I want you to think of this don't you think this kind like channel competent analogy here my nose is stuffed and it's screwing up my brain okay let's say you have an arm wrestling match right and you're pushing as hard as you can you're pushing as hard as you can but you're not but you're not falling down then if I let go for a second so there's no load you'll in storm is gonna move down onto the table really really fast so before when I was resisting you your arm was really moving really really slowly but then when I stopped resisting you even though using the same amount of pressure your arm is gonna move really really fast because there's no push back so this it's kind of the same thing going on here so this is supposed to British 27 volts when a screen which presents a load to the circuit some resistance back to the circuit is connected but there isn't but if there's a break in the line that same circuit is then gonna produce more voltage so you'll see 39 at the end of it instead of 27 so it is producing voltage but that voltage is not actually connect it to anything which is why the vote what you're seeing is higher now if you look along in the circuit the theory is then going to match reality because if I go over here and put the camera over the connector you'll see that it's quite clearly see very they're killing me so the pins are broken so there's no path so if you think of things in these terms becomes easier to figure things out one of the things I like to get across here is that most of the stuff that people think is magic and crazy engineering is is common sense and when you start to see all this common sense it then becomes that much more accessible to you what can I get you yes what happened to mother piece of my FM 20:32 died oh well luckily I have a spare you have to realize that if electronics were anything other than common sense you'd never it would have never been something that a dumbass like me would have been able to get my head around weight you can take this micro pencil weight so that the big iron is the one that died oshizu okay that means I have to try to wick a connector with a micro pencil this should be fun I'm glad that one died because that one is much cheaper ah so now the most expensive portion of it is broken okay how much of this can I get done with a micro pencil see we're gonna bring those pads back really Louis you're scraping is too hard Louis what you're doing is not properly Louis this is too much you're rough on this stuff I don't think a lot of people realize that like half of the stuff that I'm working on has been sitting in coca-cola for two years or cat piss before it gets here like there's different soldering technique that you're going to use when you're working on something that looks like it's been pissed on that's had power be going through it for two years as it's been pissed on then you're going to use on a single layer PC board that's never been abused that just needs a single component replaced so this is obviously not the proper iron to be doing this with but equipment issues let's see how long I'll be doing this for ya that's gonna take forever what do you want micro pencil yeah we did you figure out what's wrong the tip died which one just give me the name so I can buy another one or five of them at the end of