Basic Elektrical Repair

Vài năm gần đây ở khu tôi sống (Hưng Yên) nhiều nhà xưởng làm đồ Inox về lập ở thôn. Hỏi qua về quy trình làm thì có khâu bể nhúng là nghe nói độc hại nhất. Nước thải nghe một số người bảo qua một ao bèo sau đó có thể là ra mương luôn. Trong bể nhúng thành phần là gì mình không rõ, tuy nhiên như nhiều ngành nghề công nghiệp khác, lo ngại về nước thải, khí thải luôn thường trực. https://www.hoachat.vn/quy-trinh-danh-bong-dien-hoa-inox/ http://sdvina.vn/vn/7-cong-doan-trong-quy-trinh-san-xuat-inox_485.html Sẽ tìm hiểu kĩ hơn và thử phương án hạn chế tác động. Không hy vọng mấy về giải pháp triệt để, tuy nhiên đầu tiên phải hiểu vấn đề, từ đó sẽ biết nên làm gì (From it reveal the action) .  Brick fume burn with tire power seem toxin. Try get some sample then burn or try capture real smoke to investigate. Hope high temperature burn make it waste less toxic. https://semiengineering.com/entities/cadence-design-systems/

https://freedom251.com/best-laptops-under-800/ I have bad experience with Asus Laptop with dedicated Card, I remember the A52JT model (one of my bro bought in Taiwan). It have GPU issue, it too hot and lead to mobo dead (no alternative graphic), so only option is replace mobo with Chinese made (no GPU obviously).  And I see mobo design seem not good, too little heat sink. May be it's OK in Taiwan climate but in VN hot summer it's disaster. But I assume that this is a design failure.  => Vivo with GPU => big No ? https://www.youtube.com/c/Electronicsrepairschool/videos Due to highly share of Lenovo and Hp PC/Laptop so there are more chance you got an issue or user reporting about these big brand. Especially on Lenovo since they have many product line for cheap low end product. See Electronic repair school channel, most case are with Lenovo, then HP. I will do some research and report summary of which laptop brand is mostly go to repair shop from this channel later. https:...

https://en.wikipedia.org/wiki/Wireless_powerline_sensor https://www.jameco.com/Jameco/workshop/jamecofavorites/non-contact-AC-voltage-detector.html https://www.mdpi.com/1424-8220/19/8/1812 https://www.bosch-professional.com/gb/en/community/category/gsb-180-li-vs-gsb-18-v-ec/14461550-t#/main More important "soft" torque is higher in both the old and new GSB 18 V-EC models compared to the GSB 180-LI.  The max torque is a hard joint, for example if there are two similar drills, one with a light plastic chuck and the other with a "heavier" metal. The metal chuck drill usually has a higher "hard/max" torque.   Also the weight differences between the carbon brushed electric motor and brushless. ( rotating masses ) I would buy a cheaper model if the price difference is significant.  https://www.bosch-professional.com/gb/en/community/category/why-the-different-professional-range/385576-t#/main Very confusing model name / brand code https://www.youtube.com/watch?v=...

    My friend Apple Watch Series 4 have boot loop problem. It turn out that power button shorted or something wrong with it. After disconnect power button cable (that come with Mic...), the watch turn on normally. Apple Watch power button part replacement. I can not found or not have enough time to order replacement part, so I let the watch work without power button (and Mic too). The attempt on repair this minuscule button is for diagnostic only, since it is hard to find replacement part (recently I fond some but not all can by ordered). Since I need this power button to do hard reset (this require both Crown button and power home button press together as I remember). https://www.deviceparts.com/power-button-flex-cable-for-apple-watch-series-4-40mm-ori-r.html => deviceparts.com seem only for Shop/Whole store buy or personal buyer but with minimum $150 order (without shipment :( ? ). https://www.impextrom.com/en/power-switch-flex-for-apple-watch-4-gps-wifi-a1977-40mm-p10000...

https://ecee.colorado.edu/~bart/book/book/chapter7/ch7_3.htm https://cnx.org/contents/6dHkc9zc@1.48:GYAoAVIF@8/6-5-Equipotential-Surfaces-and-Conductors https://semiengineering.com/why-euv-is-so-difficult/ https://sea.pcmag.com/feature/19648/the-promises-and-challenges-of-euv-at-globalfoundries https://www.extremetech.com/computing/162376-7nm-5nm-3nm-the-new-materials-and-transistors-that-will-take-us-to-the-limits-of-moores-law Chenming Hu - Taiwanese-American - Father of FinFET.

https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries https://www.industrial-electronics.com/switching-power-supply_1-8.html https://ehs.stonybrook.edu/programs/laboratory-safety/laboratory-equipment/soldering https://sciencing.com/happens-resistor-burns-up-8556222.html https://www.leakymosfet.com/blogs/news/tips-02-trouble-shooting-no-power-issue-in-laptop-motherboard http://kythuatphancung.vn/download/lenovo-g470-g570-compal-la6751p-la6753p-laptop-schematics.html https://laptopblue.com/threads/kinh-nghiem-ve-do-main-chap-nguon-dau-vao.31067/ http://osc.vn/dinh-nghia-ve-nguon-dau-vao-mainboard-laptop-a329.html https://www.acmesystems.it/pcb_microsd https://m.phys.org/news/2018-06-recycling-plasticjapan-style.html https://divisare.com/projects/295992-rocco-design-architects-bamboo-pavilion https://en.proft.me/2018/04/9/how-add-app-purchase-your-android-application/ https://www.eevblog.com/forum/beginners/measuring-esr-of-small-capacitors/ https://superuser.com/ques...

https://blog.muabannhanh.com/tu-van-chon-loai-thiec-han-chat-luong-de-tao-nen-moi-han-dep-va-ben/88499 https://tiki.vn/thiec-han-asahi-60-06mm-250g-p6681815.html?spid=7611985&utm_source=google&utm_medium=cpc&utm_campaign=SEA_NBR_GGL_PLA_DTP_ALL_VN_ALL_UNK_UNK_C.ALL_X.1057274772_Y.54169762056_V.7611985_W.DT_A.877516657142 This maersk (mess :) Oh some 'bad' experience ab this. https://tinhte.vn/thread/kinh-nghiem-mua-iphone-cu-va-cach-test-may-14-buoc-tu-ga-hoa-cao.2683033/ https://www.ntmobile.vn/bo-cay-ss-008 https://www.ntmobile.vn/choi-2-dau-ss-022 https://www.ntmobile.vn/bo-dao-ss-101c https://www.ntmobile.vn/panh-ss-st-14-thang https://vi.aliexpress.com/item/32963867651.html alob reaction cool :) l*en th*en / rac ruoi :) simple taxomy / category 

https://www.quora.com/Embedded-Systems-Electronics-in-India-Why-cant-India-perform-as-well-as-China-in-electronics-manufacturing

https://laptopunderbudget.com/best-laptops-under-500-dollars/ https://www.tomsguide.com/best-picks/best-laptops-under-500 Some old/2nd/ refurbish Dell Latitude, HP Elite. Price around 235USD to 320USD. (5tr5 đến 7tr3).  Cấu hình thường là i5 5xxx, i7 4xx, 5xx. Ram 4G, ssd 128, màn thường HD. Full HD +300k.  Latitude và Elite là dòng business (doanh nhân) của Dell và HP. Chất lượng hơn dòng phổ thông (consumer) như Inspiron, Vostro... Dòng business có dock dưới máy để cắm thêm pin, cổng kết nối... Chất lượng build như vỏ, thiết kế mainboard... tốt hơn. Support tốt hơn vd như chờ bảo hành, hỗ trợ cài cắm, cách sử dụng vì dòng cao cấp hơn. Vostro hơn Inspiron một chút. Dell Pricision thì dòng hiệu năng mạnh nên rất đắt. HP chắc có dòng tương đương. Thực tế hiện nay Dell có chia sẻ rất nhiều linh kiện (part) giữa các dòng để tăng khả năng dùng lại/ dùng chung linh kiện. Như thế có vẻ sẽ tiết kiệm chi phí. Driver cho laptop hiện nay rất khó chịu. Từ trang chủ Dell, HP Asus, Logitec...

Tiếp tục sửa nguồn xung, lần này là mạch sạch pin li-ion Canon. Input 12x-250V, Output 8.4V/1.5A. Lần trước sửa 1 nguồn LCD Samsung SynMaster và 1 nguồn LED 10v cũng SamSung. Con LCD hỏng IC phải cấy = 5L0380, còn con nguồn LED thì đơn giản là chết diode lọc schotky. Lần này tiện thể note lại tear down 2 cái sạc Canon tàu và sạc theo máy của hãng. Rõ ràng sạc tàu lởm hơn nhiều nhưng thị trường vẫn hét giá 250k-350k chặt chém vì máy ảnh cũng thuộc hàng sa sỉ. 350k là vd như ngày giáp tết ko ai bán hàng nên hét vậy, thường thì 250k. Mình nghĩ chi phí + linh tinh mạch đó tầm 50-70k vì mạch 9v chợ trời đầy rẻ hơn nhiều. Ảnh post sau vì ĐT đang trong thời gian upgrade. Nguyên nhân: Có thể do nguồn điện ko ổn định dẫn đến hỏng j đó. Cầu chì đứt, mạch nhìn bt ko có j nữa. Kiểm tra mạch, nối cầu chì (vì mình có bóng dây tóc nối tiếp nên nôi cầu chì luôn). Đo thì có áp 300v tụ nhưng éo có áp ra. Thay IC, thay opto vẫn thế. Opto đo thử có vẻ hỏng lên thay (confirm lại sau). Th...

https://electronics.stackexchange.com/questions/163940/resistor-between-line-and-neutral-in-smps Short: Use two or more resistor in // from ~ is more reliable than one or two in series from B+. Startup resistor die is common issues. In my case LCD Samsung use later one. Common SMPS schema The resistors supply start-up current for the SMPS, after which the auxiliary winding of the transformer takes over. More often a single high value resistor (or two in series) are used from the output of the bridge rectifier (C6 + terminal), but this method will work too. They also act as bleeder resistors for the 330nF filter capacitor so the user won't get shocked if they touch the plug pins after it has been unplugged. By using two resistors in the shown configuration they make the former function more reliable and the latter less reliable (start-up resistors going open is a common failure mode of off-line switchers). Not sure if those are the only reasons, but that's what ...

http://www.squaring.net/sq/tws.html.bak Oh long time ago, I have some thought about this problem/solution. Very interesting. Miss you, I will try digging around this shit when have spare time. https://en.wikipedia.org/wiki/Path_(graph_theory) You know what ? This is mathematics - the language of the universe. This is the real work not programming shitty job.

My Dell Vostro 3500 have key Page Up always pressed. Try  https://www.keyboardtester.com/  and  wait a bit, it start to show Page Up keep pressing. So I want to disable it. (I have removed this key both cover and plastic/rubber) but no luck. So I tried to disable it by software. https://askubuntu.com/questions/245333/getting-character-key-code-mappings-in-ubuntu https://ubuntuforums.org/showthread.php?t=1218221 https://superuser.com/questions/775785/how-to-disable-a-keyboard-key-in-linux-ubuntu Run  xev -even keyboard to get keycode pressed. My Page Up key died and I can not pressed it (press not go page up) but randomly keep pressing. Page Down 117, Down 116, Home 110, End 115... I guest Page Up my keyboard is 118. I will update keyboard related problems that I've experienced later. Many interesting behaviors and symptoms. I have replaced about 10 keyboard for many Laptop and PC (always Chinese one since original not available or too expensive). Wi...

https://electronics.stackexchange.com/questions/280326/hot-air-rework-temperature-to-avoid-solder-melt-on-opposite-end Mình tổng hợp một số link mình biết và thực tế thử nghiệm về nhiệt, gió khi khò IC nhỏ. Mn có thể vô playlist này, mấy bài của gã bên Quảng Đông hay nói về nhiệt khò. https://www.youtube.com/playlist?list=PLaGly33o9_xGZbXHnndMggiRru399gcLQ Thường từ 300-500 là ok, gió nên để nhỏ. Con Gordak rẻ rách của mình lúc đo bằng  Uni-t UT 890C+ thì có lên được tầm 350 °C (chưa max). Con đo nhiệt Uni-t này mình nghĩ cũng không chuẩn  lắm nên chỉ tham khảo và chắc + thêm 10-15% phòng khi cảm biến nhiệt kém nhạy. Lý do là con khò hơi này không có hiện nhiệt độ, chỉ có volume tăng giảm. Tùy loại IC mà nhiệt khác nhau, IC Wifi thường nhiệt thấp hơn thì phải. Lúc gỡ IC cũng cẩn thận dùng dao kênh chứ không thô bạo khò dùng nhíp gắp. Nhiều thứ linh tinh phải mua quá. Mấy con dao nhỏ như này không biết đâu bán. Ngọc Thủy (ntmobile) ko biết có ko. Trên web thường ...

https://www.thespruce.com/underground-or-overhead-service-feeders-1152720

https://www.bunniestudios.com/blog/?p=3554 https://www.bunniestudios.com/blog/?page_id=1022 I copied and paste here in case the original blog go down. On MicroSD Problems The microSD ware for January 2010 was not an incidental post. It is actually snapshot of a much longer forensic investigation to find the ground truth behind some irregular Kingston memory cards. It all started back in December of 2009, when chumby was in the midst of production for the chumby One. A call came in from the floor noting that SMT yield had dropped dramatically on one lot, so I drove over to the building to have a look (this is the advantage of being in China during production — you can fix problems like this within the hour, before they become really serious issues). After poking and prodding a bit, I realized that all the units failing had Kingston microSD cards from a particular lot code. I had the factory pull the entire lot of microSD cards from the line and rework all the un...

过流保护背示灯   Overcurrent protection backlight (indicator) Guò liú bǎohù bèi shìdēng 恒流指示灯     Constant current indicator héng liú zhǐshì dēng 恒压指示灯     Constant voltage indicator héng yā zhǐshì dēng https://www.ntmobile.vn/nguon-5a-qj3005t 3005 mean 30v 5A

https://www.youtube.com/results?search_query=g570+board+repair Sorin soldering tutorials:: Basic Soldering, Advanced Soldering and Microsoldering oh, it included a fix on Samsung S7 ? IC MAX 77843 ? Amtech flux. Lenovo G570 motherboard test: You can search G570 schematic on the Internet. One of it is here: https://laptopblue.vn/download/1242/lenovo-g470-g570-compal-la6752p-la6754p-la6759p-laptop-schematics.html In PDF format. Other format like OpenBoardView I am not used since I have less experience/ time using these software. Sorin dialog a motherboard. A reapir lesson  He will draw something... TLD dạy phần nguồn No2 VN https://drive.google.com/file/d/0B6IqcVTk0jpYZlJMUWpSdE9uTlE/view Chạm B+ Buy stuffs: https://www.ntmobile.vn/son-den-relife-uvh900b https://www.ntmobile.vn/keo-t7000-50ml https://www.ntmobile.vn/panh-quick-cong-qa-15 https://www.ntmobile.vn/panh-cong-st-17 => this one like Sorin use. ht...

1.Hold button (rounded front button) to turn off device first. 2. Hold up (rounded front button) but in up position about 4 seconds, it will enter setup mode. 3. Change setup: It have some settings like unit meter/inch, error correction etc. I'm too lazy to make video about it. You know it take time to editing. I will update some photo about it and real use case review later. Notes: I've got problem when using this LS-P, I often press up button two time for distance measure, but one moment I have no idea why my unit have changed to inches which I am not familiar with. So I have dig into Internet without luck, then dive into  manual note in Chinese. After translation I found out how it work.    It's is some how like Hakko Fx-888 or some other device with limited button for user interface like Garmin eTrex... And from view of a software engineer, It not hard to understand the mechanism under it.

Rất nhiều dòng laptop có lỗi từ design hoặc vật liệu làm vỏ (A, B, C, D). Laptop đời cũ (pre-2010 ?) có vẻ chắc hơn, vỏ dày, nhựa vừa cứng vừa dẻo (bị méo chứ không bị bể). ... Fix 1. Keo nến 2. Keo AB 3. Keo 502, keo con chó ? 4. Thay mới => méo dùng vì đắt, ko sẵn hàng, nếu có vỏ tháo máy thì ok. 5. Bản lề nhìn cũng không phức tạp => nếu có máy móc chế được hay thậm chí dùng CNC cắt.     Theo tìm hiểu trên mạng thì keo AB hay Epoxy glue có vẻ chuẩn. Mua được keo chuẩn hay không thì là chuyện khác.     Keo nến theo ô người Nga này cũng ok ? Nhất là với mấy dòng lap giá rẻ. Mình cũng chỉ dân hobby rác rưởi nhưng ngay từ đầu cũng tính dùng keo nến tạm trước khi thử nghiệm keo AB ... Keo nến nó dẻo nên có thể tháo ra sửa lại nếu cần dùng máy sấy hay khò nóng vừa là bong.     Dùng vít, cái này chắc bán nhiều nhưng chưa có kinh nghiệm nơi mua cụ thể, trên mạng cũng nhiều nhưng nhìn ốc tiện không chất lượng lắm. Anyway ví...

https://en.wikipedia.org/wiki/Four-terminal_sensing http://axotron.se/blog/multimeter-repair/ IC hy12p66 http://www.kennethkuhn.com/electronics/short_circuit_tracing.pdf http://www.hycontek.com/wp-content/uploads/DS-HY12P65-TC.pdf https://www.manualslib.com/manual/918770/Sanwa-Pc20tk.html?page=34#manual https://www.sanwa-meter.co.jp/prg_data/goods/img/PH41381902027.pdf https://github.com/pingumacpenguin/DTM0660-flasher-arduino-sketch/blob/master/STM32-DTM0660-24c02-Updater.ino https://www.eevblog.com/forum/testgear/an8008-us-$19-10000count-1uv-0-01ua-0-01ohm-resolution-meter/225/ https://www.sanwa-meter.co.jp/prg_data/goods/img/PH41340354145.pdf http://www.kerrywong.com/2016/03/19/hacking-dtm0660l-based-multimeters/ https://www.sanwa-meter.co.jp/prg_data/goods/img/PH41381902027.pdf https://en.wikipedia.org/wiki/Internet_Archive https://en.wikipedia.org/wiki/Methamphetamine http://news.mit.edu/2008/self-assembly-0814 https://forum.arduino.cc/index.php?topic=425...

My Dell Ultrasharp monitor model S2340l got error on vertical line all screen and black rounded corner. It like this one, start at 4:58 It is a LG but board and IC seem used same as Dell one. My monitor in worst condition than this LG, it have black rounded corner and vertical line moving instead of horizontal. https://www.aliexpress.com/item/32896809893.html Courier  HKPost vs Singpost https://server6.kproxy.com/servlet/redirect.srv/sruj/sqmpfggpv/sopq/p2/forums/shipping/t/2157865/singpost-vs-hongkong-post/1 https://www.fasttech.com/forums/shipping/t/2157865/singpost-vs-hongkong-post/1 Damn it ban VN IP. SG Post allows internal batteries and eliquids which HK Post prohibits.. Compare taobao, Alibaba and Aliexpress https://www.facebook.com/VanChuyenHangTrungQuocQuyNam/posts/1652963201424327/ https://quynamchina.com/tu-van/alibaba-taobao-1688-tmall-co-gi-khac-nhau.html https://forums.voz.vn/showthread.php?t=7355082&page=151 Yeah some other stu...