Toshiba Satellite C850 - Why Is It Not Powering On? (Part 1)

[@danarepouille1381]

Your videos are a valuable resource, which anyone can use to fault-find these laptops. It is tedious to research using schematics and boardview diagrams, but your videos make the process much simpler. As you build your library, taking measurement readings of working motherboards, your channel will become an essential GO TO resource for anyone who needs to find faults in their motherboards. Thank you for your tedious work.

[@danarepouille1381]

The last "no power, no POST" laptop I repaired only needed a BIOS reset. So one of the first steps I take is to disconnect the main battery, and remove the CR-2032 battery. This allows me to check the battery voltage levels, and it also forces a BIOS reset. When I connect the charger, the motherboard either starts and and scans for memory and such, or it remains dead. (I like to keep the fan connected to show signs of life.) Then I begin looking for shorted power rails. I know that your preferred method is to follow the DC_IN voltage around the board. I have no problem with that. I am still too new at this to feel comfortable probing around a "hot" board with my meter. I have already killed a transistor (MOSFET driver) by shorting it to a pull-up resistor. So yes, I am gun-shy with meter probes on hot circuits.

[@rened4804]

Thank you for your videos 👋👋👋

[@x-fix]

I was also trying to messure the 19V on the small cap at 11:40 and guess what.... I blowed it by that. I could follow your guide until that moment. Now I have a short here and need to replace that cap. Not sure why that happened while messuring the volts...

[@therepairshare673]

While it is always safe to measure in DC volts (as opposed to continuity), the components are very small and close together, so there is always the danger of shorting between two components while taking measurements. I wonder is it possible that when you placed the probe to the positive of the 19V capacitor, that you also touched off the 3.3V capacitor and maybe shorted that component or something on that rail?

[@x-fix]

@@therepairshare673 Well I cant be sure for 100% that I didnt touch the other component but I was careful and tryed to touch it on the top.... Do you know by any chance what values this component had?

[@therepairshare673]

@@x-fix Why don't you send me a pic of the area to [e-mail] and point out where you are detecting the short. I may not be able to identify the component, but we might be able to identify where the short is and remove it.

[@x-fix]

@@therepairshare673 Sounds great! I will get some pics done and send it over! :)

[@x-fix]

@@therepairshare673 I think I found the problem. The IC 1225c under those caps is blown. It has a hole. I just noticed it under the microscope. This would explain why the cap was lightning up...

[@juanitoseme8632]

Thanks

[@x-fix]

Hello! This video is amazing to anyone who is troubleshooting his machine! Very helpful! Is there a way you could tell me what values the capacitor has that is placed above the 2R2 resistor right at the beginning of the video near the 19V power line? I noticed that this one blowed up and got seperated in 2 halfs so there is no way for me to messure it. I also checked out the schematics but Im not able to find it there....

[@therepairshare673]

Sorry, I brought it to the recycling centre already. That is a 19V power rail so the capacitor has to at least support 20V-25V, and I would guess either 22uF or 10uF. Unfortunately no schematic/documentation from Toshiba to confirm!

[@x-fix]

@@therepairshare673 Thanks a lot for the reply! It helps!

[@x-fix]

@@therepairshare673 Hey buddy! I just wanted to say thanks again for your help on my Toshiba Laptop repair! I also mentioned you and your channel in my latest video that I made about this repair! :)

[@therepairshare673]

@@x-fix Thank you. I'll be sure to check it out. 👍