Asus Chromebook CX1700 not charging, board repair. Very strange design!

Added: 2026-05-25

[00:00:00]Hello. So, we're back in this time. We have a huge Asus Chromebook. I think it's a 17 in uh pressing the power button. Nothing happened. It just did. Let's plug a charger. So, USBC plug in the charger.

[00:00:18]And the meter is coming only 5 volts.

[00:00:23]4.5 volts 2.8 amps you can see. So, basically it is charging. Uh the PD controller is not uh speaking with my charger for some reason. Pressing the power button. Now nothing happened. The current is not changing. Holding the power button down and nothing happened. It is possible to be uh because it's not getting reset. If you hold the power button down the PD controller, it will get reset. But because it's not getting reset can be a problem between the EC chip and the PD controller because can be a communication issue between EC chip and PD or from the PD to the charger and we don't know for sure where is the problem.

[00:01:09]I will say let's quickly open the laptop and let's have a look inside.

[00:01:14]And the laptop is open. Yeah, just a tiny board a small battery. I don't understand why they didn't put one more battery here or like a big battery. I mean, so much waste space or I don't know, move the speakers here and, you know, put another a bigger battery.

[00:01:37]Yeah. Anyway, let's see. So, we have the battery here. Let's unplug the battery to reset the board. We don't have a bias battery. Let's plug the USBC charger.

[00:01:50]Plug in the charger and same story.

[00:01:52]Nothing changed.

[00:01:55]Of course, it's charging. I can feel the coil is getting is getting hot.

[00:02:00]Wait, it's not charging. The battery is unplugged. So, why this coil is getting hot?

[00:02:08]Is making no sense.

[00:02:10]I mean, it's taking 2.7 amps, but the battery it's unplugged. So, who is taking the current? Huh? Let's come with the thermal camera.

[00:02:20]So we have the thermal camera.

[00:02:23]Check there. You can see the coil is getting hot.

[00:02:30]Wait a second. We can see something more apart from the coil. So this is the coil which is creating a main power rail.

[00:02:36]Then here what is this heat? This one.

[00:02:41]So the heat is from the cable, right? So if we unplugging the cable, this cable, the heat is gone.

[00:02:52]Yeah.

[00:02:53]Okay. So if we check now. Yeah. Check here.

[00:03:00]You think 1.7 amps? L. This is proper hot. That's crazy. One second. One second. Let me plug the battery. I'm pretty sure this laptop is working right now.

[00:03:11]So plug in the battery.

[00:03:14]Check there. Check there. You seen 14 volts? 14 volts, 2 amps. It's working fine. We fixed it. I can't believe.

[00:03:23]Yeah. Just understand how useful it's a thermal camera. So now the laptop it is working fine. I'm pretty sure the laptop it will come on. Uh yeah, it's it is on.

[00:03:32]You can see it.

[00:03:34]But here something is m hot and not sure what what is this. This is some kind of damage here.

[00:03:46]Wait, what is that? Let's check under the microscope. Here is something dodgy.

[00:03:51]What is that?

[00:03:53]Oh lord. So, this is actually liquid damage, right?

[00:03:58]Let me take out the thermal camera.

[00:04:06]This is liquid damage. And we can see where actually it has a burn mark here. Ah, liquid damage.

[00:04:18]And there we have a MOSFET and another power supply.

[00:04:23]I mean, I never seen something like that. So, check here. Yeah, this is a power supply. Yeah, same like the one which is creating the main portal. You have two dual MOSFETs and you have you have a coil on the middle.

[00:04:35]Uh let's clean it quickly.

[00:04:38]Uh cleaning the liquid damage.

[00:04:42]Yeah, of course that it will not fix the problem. We have a shorter capacitor.

[00:04:47]Now let's come with the power supply with low uh low voltage on these capacitors. And here is taking 2 amps and here here is not short.

[00:05:01]No, it's not short. Okay.

[00:05:05]Let's uh let's connect this cable again.

[00:05:10]I mean, that's all. We fixed it.

[00:05:14]Let's plug the charger.

[00:05:19]Plug in the charger, but you can't see it. No, we didn't fix it. Uh let's bring the thermal camera back on this to the screen.

[00:05:28]And what is that? Huh?

[00:05:32]One second because we have to spot the problem.

[00:05:37]So the problem is this capacitor. This one you can't see it right. This one.

[00:05:44]Uh let me focus. So if I remove this capacitor, all the problems goes away.

[00:05:50]Say hello to my little friend. And we have no heat. Check that. No heat.

[00:05:56]No. No heat. No. No.

[00:06:01]Great. So now if we are plugging the battery, plug in the charger, 14 volts. You can see that it's getting reset because uh the bias is getting reset every time you disconnect the battery. So it's taking 2.6 amps with 14 volts.

[00:06:22]And of course we have picture.

[00:06:25]But I never seen something like that.

[00:06:26]You seen it? I mean if you are on this field. Yeah. Just check here. Yeah, you have one you have you have one big power supply this one with two MOSFETs dual MOSFETs creating the main power rail. Then here you have another power supply which is creating another power rail.

[00:06:45]I'm assuming this power rail probably I mean this is quite a stupid design. So look what I think. I think one USBC is connected to one power supply and the other USBC is connected to the other power supply which if you ask me definitely something stupid and this power supply it is working.

[00:07:08]Yeah.

[00:07:10]Yeah. The charging current is going up.

[00:07:14]I mean the way how um the way how the laptops are built you have two USBC ports or more then all are coming together to one input of uh of one power supply which is creating the main power and charging the battery on the same time.

[00:07:32]So this looks like some kind of like a waste uh waste design.

[00:07:40]It's just a waste. It's no point having two power supplies.

[00:07:46]Yeah. Yeah, indeed. That's the design.

[00:07:48]So, this one is getting hot, but not this one.

[00:07:52]That mean the output of each power supply is connected together to the battery and the main power rail. Well, I'm happy I fixed it. have in mind if you have this laptop basically you can uh what you can do you can remove this power supply and you still have this one or you can remove this one just unplug the cable and you can still have this one. Yeah.

[00:08:18]Interesting, right?

[00:08:26]Pressing the power button and the laptop it is coming on. Yeah, it is working fine. We have some users there.

[00:08:34]Well, I'm going to stop here. I will say thank you for watching. You know, like, subscribe if you like the video and see you on the next one. Wait, what is that?

[00:08:43]Okay, now it's fine.

[00:08:48]Bye.