Battery Connector Shorted on Laptop - Page 1
Forum section: electronics / repair

author: canadaboy25
author_rank: Regular Contributor
timestamp: December 09, 2015, 11:52:19 pm
content: Hey guys, I screwed up my laptop.I have a Toshiba Satellite A205. I've been having issues with my battery but that's a separate issue. I was probing the connector on the battery while it was running then I very professionally shorted (one of the two outside I think) two pins together. The laptop instantly shut down and there were no LED's on. I pulled the plug and the battery and put them back in then the charge LED's came back on. The laptop will power up but turns right off after about 8 seconds. The BIOS screen shows up and sometimes it will flash onto the Linux failed to boot screen so I know the processor is working. If I go into the BIOS or the boot selection it comes up fine but still turns off after the 8 seconds or so. This happens without the battery as well.I know that this laptop will run perfectly fine without a battery because I used to do it all the time with no issues.I'm thinking that it's a power supply issue because that's where I was poking around but I could be completely wrong about that.I have fairly good soldering skills with plenty of smd experience and also an oscilloscope if it comes to that.I have attached a pdf with what I believe is the power supply schematics for this laptop so hopefully that can be of some help.Any suggestions will be greatly appreciated.

author: amyk
author_rank: Super Contributor
timestamp: December 10, 2015, 04:07:25 am
content: I haven't inspected the schematics in any detail but I think the problem is with the "power good" watchdog. The EC will turn on the rest of the system and then observe that signal from the other ICs, if it doesn't see power good from them all it turns it back off after a short period.Get all the datasheets for the ICs, read them, and start probing (carefully).

author: poot36
author_rank: Frequent Contributor
timestamp: December 10, 2015, 06:07:45 am
content: I am going to hazard a guess that you have fried the battery chargeing control mosfet or its associated current sense resistor. Both of these things will cause the condition described due to a fault been detected and the laptop shuts itself off to protect itself any potentialy your property from going on fire from an overcharged battery.

author: sdk.61
author_rank: Contributor
timestamp: December 11, 2015, 07:59:55 am
content: hi do you have an external monitor screen when the screen is inserted or malfunctioned, check the North Bridge, South

author: Rasz
author_rank: Super Contributor
timestamp: December 12, 2015, 04:23:57 pm
content: did you short it while battery was plugged in/charging?I agree its probably charging circuit, q506 r506 and L501

author: canadaboy25
author_rank: Regular Contributor
timestamp: December 12, 2015, 06:49:22 pm
content: Quote from: Rasz on December 12, 2015, 04:23:57 pmYes, the laptop was running while the connector was shorted.

author: Monkeh
author_rank: Super Contributor
timestamp: December 12, 2015, 07:30:22 pm
content: BATT+ to BAT_ID would do the trick.I'll put money on the EC being half fried.

author: canadaboy25
author_rank: Regular Contributor
timestamp: December 12, 2015, 09:28:50 pm
content: Quote from: Monkeh on December 12, 2015, 07:30:22 pmWhat exactly do you mean by "do the trick?" Am I supposed to short these pins to get it to work or is that what would have shorted the chip?Also, what chip is the EC that you are referring to?

author: canadaboy25
author_rank: Regular Contributor
timestamp: December 12, 2015, 10:37:14 pm
content: I've updated the schematic file in the original post because the other one wasn't exactly the same as my laptop.

author: Monkeh
author_rank: Super Contributor
timestamp: December 12, 2015, 11:46:18 pm
content: Quote from: canadaboy25 on December 12, 2015, 09:28:50 pmShorting pins again isn't going to fix anything..The EC is the Embedded Controller, what Apple would call an SMC. The various data connections from the battery run there, and it will not be even remotely tolerant of being shorted to BATT+. And it's one of the parts which can just turn the laptop off by itself.Please be positive of which schematic applies to your laptop.

author: canadaboy25
author_rank: Regular Contributor
timestamp: December 13, 2015, 12:37:44 am
content: I am almost certain that the new schematic I linked in is the correct version. All of the traces between certain chips and diodes I checked have all been the same on the board as on the schematic.Is it going to be possible to find the power_good signal source and apply the voltage it is looking for to that pin just to get it to stay running?

author: Rasz
author_rank: Super Contributor
timestamp: December 13, 2015, 05:56:58 pm
content: Quote from: canadaboy25 on December 13, 2015, 12:37:44 amits not that simple, you BROKE something, start looking for that broken component(s)do you have a meter? check all the bigger mosfets for shorts, check charging circuit components i listed q504 q505 l501 r500 c508

author: canadaboy25
author_rank: Regular Contributor
timestamp: December 14, 2015, 12:02:02 am
content: Quote from: Rasz on December 13, 2015, 05:56:58 pmq504 is a p-channel mosfet and q505 is a dual n-channel enhancement mode mosfet so don't these components need to be out of circuit to be tested?If not what is the proper procedure for testing them in circuit?

author: canadaboy25
author_rank: Regular Contributor
timestamp: December 17, 2015, 04:29:31 am
content: I just don't want to go to the effort of desoldering all of these chips if it isn't necessary.