CyberpowerPC Tracer Laptop Motherboard Repair and component identification - Page 1
Forum section: electronics / repair

author: ThatGuyUKnow
author_rank: Newbie
timestamp: July 16, 2019, 06:38:04 pm
content: Hello,I have a CyberpowerPC Tracer laptop I am working on for a friend. The motherboard has a part number of: MBPNFSV158-1311. The item will not boot/power on. There is a power issue as the lights on the keyboard flicker and the computer shuts off quickly. The flickering does not follow a pattern.I started by looking for obvious signs like corrosion or damaged components but could not find any. I put the motherboard under the thermal cam and the ethernet controller IC lit up like a christmas light and almost instantly jumped 10 degrees celsius before the computer shut off and it cooled down. I checked the surrounding components for shorts to ground and found none. I replaced the Realtek 8111GS chip and I no longer had an issue in that area of the board but the motherboard would still not stay on. I found on the opposite side of the board on one of the traces that go to the chip that another component was extremely hot. It would be hot regardless of the PC being powered on or not leading me to believe it might be part of the main power rail and shorting to ground. The item has the marking "21l05" with three legs. It is a slightly bigger package than the surrounding transistors and has a dot indicating the 1 pin. I tested the item using diode mode. One pin being where the dot is, two pin being the solo left pin, and the three pin being the top right pin.The measurements are as follows.Red Probe Pin 1 to Black Probe Pin 2 .760VBlack Probe Pin 1 to Red Probe Pin 2 .047VRed Probe Pin 2 to Black Probe Pin 3 .065VBlack Probe Pin 2 to Red Probe Pin 3 .065VRed Probe Pin 3 to Black Probe Pin 1 .095VBlack Probe Pin 3 to Red Probe Pin 1 .095VI haven't been able to match the markings to any component package online and without knowing exactly what it is I am not 100% certain it is bad. The readings and the 10 degree celsius increase when the item is plugged in makes this the leading candidate and probably what killed the ethernet chip in the first place.I have included pictures of both the Realtek chip and the component in question.Regarding the path from the component to the ethernet chip. It leaves pin 2 of the component Q19 to two capacitors at locations C298 and C319 which are next to each other. It then heads to the other side of the board to capacitor C222 and then to the ethernet chip.Any help would be appreciated.Thanks,Jared

author: fzabkar
author_rank: Super Contributor
timestamp: July 17, 2019, 01:17:54 am
content: Could it be a PA102FMG P-Channel Logic Level Enhancement Mode MOSFET?http://www.cheertech.com.tw/Niko-sem/Data%20sheet/PA102FMG.pdfFWIW, this Dell circuit uses the PA102FMG as a 3.3V, 201mA supply for the LAN section:http://notebookschematic.org/data/NOTEBOOK/attachments/SC/products_files/Dell%20Inspiron%20M4010_DELL_Wistron_Ansenal_DJ1_AMD_UMA_RevA00.pdfThere may be other circuits of interest to you:https://www.bing.com/search?q=pa102fmg+filetype:pdfEdit: See page 35 of this PDF:https://laptopblue.vn/download3.php?id=1631The transistor is being used as a power switch for the 3.3V LAN supply. I don't know whether it performs the same function in your case.