I am learning that the nice thing about these Dell motherboards is that each power rail has a jumper, such as PJPx01, which you can use as a test point, an injection point, and most useful of all -- you can wick away the solder on the jumper to isolate the power rail, so you can take measurements on that rail alone. Very cool feature.
I loved. I read the comments and reflect on why you invite us (viewers and/or subscribers) to participate. Thank you very much for sharing. An affectionate greeting from Mexico. PS: A year later? Well, I didn't know your channel. I will do another tour of all your videos although it will take time (already at home after dinner) because I find it very interesting since I like laptop repair. Please, recognizing in advance the abuse of your time, keep uploading content and we will be on your side here.
BRILLIANT! Thank you so much! I have been refurbishing Dell Inspiron 5570 and 5770 laptops that have the CAL60 LA-F114P motherboard. I have learned how to repair the PS_ID circuit, and I have replaced a shorted power jack. Now I am faced with the classic issue when the charger goes into protection mode due to a short on the main power rail. Your video is the best tutorial I have ever seen on UA-cam for this issue. Many others demonstrate power injection to trace shorts, but you are teaching a Master's class. Thanks again!
Well, I tried injecting 1V@1A at the resistor, but the voltage on my bench power supply did not drop very much. It drops to 0.2V when connected to a true ground, but it only drops to 0.8V when connected to the resistor of the 19V line. I tried increasing from 1A to 2.5A, and nothing got warm on the board. The resistance of the 19V line is only 0.2 ohm, so I don't know where the current is going. I will keep trying.
My current theory is that the very first high side MOSFET that connects to DC_IN is dead. I will try to check measurements between source, drain, and gate to see if it is internally shorted.
@@danarepouille1381 Might be interesting to work along the troubleshooting process for that board in a video. Can you just confirm that the model number of the motherboard is CAL60 LA-F114P - is that exactly how it is written on the board itself? I will see if I can find a schematic.
@@therepairshare673 The schematic I have been using has a filename UMA_LA-F114PR10_20170726.pdf. The board I am working on now is a CAL60 LA-F114P Rev 1.0 (A00) 2017-09-04. I have one donor board that is also Rev 1.0, and four donor boards that are Rev 2.0 (A01) 2018-05-04. My donor boards are missing TVS diodes or USB ports, but are otherwise functional. Any board that has a 7th Gen Intel CPU I make a donor board, since they are not fully supported by Windows 11. My current theory is that PQB11 is dead on the board I am troubleshooting now. I am just not sure how to prove that, short of removing it and running a jumper wire across it.
@@danarepouille1381 Great, I've got the same UMA_LA-F114PR10_20170726.pdf file, thank you to badcaps.net. Can you clarify at which resistor you are injecting voltage and observing 0.2 ohms resistance?
Thank you so much ! great video.
I am learning that the nice thing about these Dell motherboards is that each power rail has a jumper, such as PJPx01, which you can use as a test point, an injection point, and most useful of all -- you can wick away the solder on the jumper to isolate the power rail, so you can take measurements on that rail alone. Very cool feature.
Thank you
I loved. I read the comments and reflect on why you invite us (viewers and/or subscribers) to participate. Thank you very much for sharing. An affectionate greeting from Mexico.
PS: A year later? Well, I didn't know your channel. I will do another tour of all your videos although it will take time (already at home after dinner) because I find it very interesting since I like laptop repair. Please, recognizing in advance the abuse of your time, keep uploading content and we will be on your side here.
BRILLIANT! Thank you so much! I have been refurbishing Dell Inspiron 5570 and 5770 laptops that have the CAL60 LA-F114P motherboard. I have learned how to repair the PS_ID circuit, and I have replaced a shorted power jack. Now I am faced with the classic issue when the charger goes into protection mode due to a short on the main power rail. Your video is the best tutorial I have ever seen on UA-cam for this issue. Many others demonstrate power injection to trace shorts, but you are teaching a Master's class. Thanks again!
Well, I tried injecting 1V@1A at the resistor, but the voltage on my bench power supply did not drop very much. It drops to 0.2V when connected to a true ground, but it only drops to 0.8V when connected to the resistor of the 19V line. I tried increasing from 1A to 2.5A, and nothing got warm on the board. The resistance of the 19V line is only 0.2 ohm, so I don't know where the current is going. I will keep trying.
My current theory is that the very first high side MOSFET that connects to DC_IN is dead. I will try to check measurements between source, drain, and gate to see if it is internally shorted.
@@danarepouille1381 Might be interesting to work along the troubleshooting process for that board in a video. Can you just confirm that the model number of the motherboard is CAL60 LA-F114P - is that exactly how it is written on the board itself? I will see if I can find a schematic.
@@therepairshare673 The schematic I have been using has a filename UMA_LA-F114PR10_20170726.pdf. The board I am working on now is a CAL60 LA-F114P Rev 1.0 (A00) 2017-09-04. I have one donor board that is also Rev 1.0, and four donor boards that are Rev 2.0 (A01) 2018-05-04. My donor boards are missing TVS diodes or USB ports, but are otherwise functional. Any board that has a 7th Gen Intel CPU I make a donor board, since they are not fully supported by Windows 11.
My current theory is that PQB11 is dead on the board I am troubleshooting now. I am just not sure how to prove that, short of removing it and running a jumper wire across it.
@@danarepouille1381 Great, I've got the same UMA_LA-F114PR10_20170726.pdf file, thank you to badcaps.net. Can you clarify at which resistor you are injecting voltage and observing 0.2 ohms resistance?