Toshiba Satellite A300 no power

[Stereo25131]

Hello!

I have a 5 years-old Toshiba Satellite A300-15A and after trying to open it so as to reach the fan and clean it, I messed with the screen ribbon-cable and 2 pins were bent. However, the notebook gave signal to an external monitor, which was a good sign till then.

Meanwhile, the power cord (19V 6.3A) had already had contact problems with the DC jack, so battery was poorly charged.

Then, I decided to request help from a local laptop repair-center. Technicians checked it, repaired the ribbon cable pins but told me that the laptop had no signal of power/wouldn't turn on with the power cable on ( I assume they used a universal power cable). They said that it probably had a short circuit problem and that, according to their temperature measurements, they believe it's located in the area marked on the following photo.

Now, the problem is still unsolved and I doubt there is a short circuit. I have no power cable and battery is probably drained out of power, so I don't think I can check anything.
But I found out this trace/scratch on the pcb, exactly next to the area they had indicated.

Could this be the problem? Please, if you have any experience, give me your advice as to what I should do next.

(I apologize for the long post, but I think some details may be useful)

 

[Stereo25131]

Well, tell them to repair those traces, and to solder in the power connector properly (repair the cold joint).

That's what I m going to do at last!

I found that there is a small missing diode (I think) just under the red circle on the picture, so that's the problem I believe...