 Hey guys, Kevin here. Today we're going to talk about when you turn the printer on is now going to be on. It could be something as simple as a burned power supply, but today we're going to focus on a toasted motherboard. A good hint is if you smell grilled cheese whenever you turn on the printer, probably the motherboard is fried. I'll post a link about how to remove this scanner above, so you can click and see how I open it up and remove the scanner, so I don't have to repeat myself. There's a screw above and then there's a screw below the power supply. Sorry I didn't catch that when I removed the screw from below. Just look down, you can see it. Remove those two, you can get the power supply off. Hook up a multimeter, you can check the power supply and I'm not going to repeat here. The cable is pretty easy to remember. You got a white cable, then you got a black cable. Then you got a white cable with black wires. Both those two cables, the blue side is facing left, the metal side facing right. There are two screws on the top and there's a tiny cable on the bottom and the whole thing just slides right out. This chip is what you'll pay money for. Luckily, most of the malfunction chips are pretty cheap to replace. This driver chip sometimes gets burned. I'll show you how to replace it in the next video. If I'm going to make another one. Anyway, there are lots of people who view my video but not many people like it. So I'm starting thinking maybe you guys don't need this really deep knowledge about how to fix stuff. Maybe I'll just say something simple. Anyway, this is my first try. We're going to work on those two really, really likely to be burned. This is the first thing you want to check. Those later, if you shine with your iPhone with a different angle, really easy to see the markings. If you need any parts, you can go to bchtechnologies.com, put in your parts. Today, we're talking about electronic boards and assembly. Then on the life hand side, you're going to see all the selections. We're going to select a main board. Here's the driver chip we talked about earlier. I have a problem. Say it's only like a couple of bucks. Here's the transistor pair A222 and C6144. If you don't know about transistors, don't worry. I'll explain really, really simple. A222 is a PMP transistor. The other one will be MPN transistor. You may have a different transistor on the second transistor, but the first one always the same as A222. Imagine you glue two dials together. The conventional current can only flow according to that arrow, the direction of that triangle arrow. The positive can flow from 2 to 1, but it cannot flow from 1 to 2. Because that triangle is facing the wrong way if you want to flow from 1 to 2. You can test it with this little tester. I highly recommend you get one. It can get from eBay for $10. It's a 12864 tester. You just have the letter facing you, putting on the first three pins, push the red button. I'll tell you if it's good or not. It confirms this PMP and 1 is base, and 2 is collector, 3 is emitter. If you only have a multimeter, and we can test it with a multimeter, it only confirms that this is not bad, but it doesn't confirm that this is good. A conventional current can go from 2 to 1, and not from 1 to 2, and then from 3 to 1, but not from 1 to 3. Okay, that was a new transistor. To test those old transistors, you cannot test them on board. You have to take them off. If the first transistor is PMP, the next transistor got to be NPN. There's no exception. And the same thing as PMP, just everything is reversed. The two triangles are reversed. So now the current can flow from 1 to 2, but not from 2 to 1. Oh, by the way, when I say 1, 2, 3, those legs, the letters on the transistor has to be facing you. So that's the correct orientation. Look at the board. Use a permanent marker, write down 2 and 6. 2 is 8, 2, 2, 2, and 6 is 6, 1, 4, 4. The letters on the transistor should be facing the number you wrote. So when you bend it down, you cannot see the numbers on the transistor. Anyway, do not do this. Do not test them on board. It doesn't make any sense. Again, you don't have to buy any of those test increments. If you happen to have solder iron like me, just go desolder it. If you don't, maybe search YouTube. Fat guy doing setup. Oh, no, that's not what I'm here for. Anyway, how to solder desolder without solder iron? So here are some suggestions how to solder desolder without the solder iron. Also solder iron is not that expensive. It's really nice tool to have around. Normally, if those transistors are defective, I'll just go ahead and change them without further test the driver chip. So you can see it takes a long time to self-test. It probably is bad. And I'll just throw it there and prepare to replace them. I remember there are a number of letters towards us. And we're going to put a number 2 slot. Okay, boys and girls, don't try this at home. Before I fully just put all the screws back, I'll just connect couple cables and try it out. The most important is this front panel cable and the power cable. Hold your breath. Nice. It's going to air out because the loss cable is not connected. When you put it in, the board is sitting on that little notch. And on the left side, you have to pull a black lever back Then when the black lever falls back, it goes right into the 2 slots on the motherboard. And you can see here. So when you go back, it goes to the middle. The rest is easy. You can refer to the earlier part of this video. And also, again, I post a previous video about how to take the scanner off. You can get a link above. Okay, guys, ready?