Dell Latitude 5400 LA-G891P - Not Powering On 

Yes, we do. I learned from this. Thank you very much. For me you have the best videos teaching how to fix laptops of RU-vid.

You spoil me with Dell motherboard repairs. Thanks!

This topology of the input voltage is called NVDC or NarrowVdc topology. It's the same thing you see in macbooks with the well known PPbus_G3H where the actual main power rail of the system usually matches this of the battery. As someone else writes here in the comments, you can't measure this voltage directly on the coil, it's better to measure it on a capacitor because of the very high switching frequency of the coil. The thing is that manufacturers use this topology in order to minimize the cost of the BoM since lower voltage means you can use cheaper components. The total efficiency of NVDC though is lower that this of a traditional topology.

Hello, coil impedance causes proportional changes in amplitude and phase to occur in the coil voltage I think, thanks I like your videos !

With your good explanations and the comments of the colleagues who participate: the name of your channel (the repair share) if it is true! Thanks a lot for sharing. Please keep uploading content. All the best.

Thanks teacher

You are doing a great job explaining. The problem with L1 is that it is going to be alternating pulses due to it being driven by the two mosfets on each side. While many multimeters can read a FREQUENCIES of 9.99Mhz or more, they can't measure voltage at that frequency. Some cheap meters only go up to 999Hz while Flukes do around 10-15KHz I believe, but even this is too low as many operate between 34Khz to 4.? MHz on some Apple supplies

Accurate failure analysis of yours although fortunately nothing was wrong with that MoBo (misdiagnosed by the other person). Thank you very much for sharing and of course for me it is not wasted time or effort on your part but on the contrary they are valuable. An affectionate greeting from Mexico. PS: Unfortunately the data sheet of that ISL9538C IC (only 4 pages) does not show us the function and/or identification of each pin (there are 32 in total) much less a broader explanation of the theory of operation of this component in particular. In 2017 Renesas acquired Intersil (a merger). Renesas an American company based in California (USA). Many semiconductor manufacturing companies have complained of plagiarism (piracy) even in court. It's easy to figure out why you limit your technical information, right?

Thanks for your videos. Can I ask two things 1. What is VCC 2. From where you get your boards. 😊❤

How will you take the photo of the board? Please to let us know. 🙂

Nc video ,from where did you bought that motherboard ?

I have dealt with these motherboards for a while and the issue seems to be USB Type C connector related. They are either damaged or the controller burnt out.

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First like 😂 first comment 😊 very nice channel

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