Item: Toshiba Satellite Pro L450-12x laptop
Fault: Nothing is displayed on the screen or via an external monitor through VGA cable
Background: The laptop has over heated several times and on one occasion it has shut down completely.
Initial investigation: Tested on battery only and AC (with and without battery) connected and found power led lights green, battery and AC connected green. I press the on button and the fan starts up at a high speed for around 3 secs and then goes off. There is no disc activity light, but I can hear and feel it working - I have tested the hard drive in another machine and it worked fine so I'll rule that out. After about 2 minutes the fan will spin up again for 3 secs and then off again.
Whilst taking the fan out I found a nice lining of dust, dirt and lint which had blocked the air flow almost completely - definitely a cause for the over heating.
I have tested DC voltage across the following caps:
PC71 - 1.23V
PC73 - 0V
PC56 - 3.3V
PC57 - 5.1V
PC103 - 19.5V
Caps PC71 & PC73 (OA4's 220uf 6.3v) wouldn't read in circuit. I took these two out and found high esr values. I didn't have any SMD caps so to test I replaced temporarily with rubycon ZL's - unfortunately this has not fixed the issue.
Any advice greatly appreciated as I am not sure what to test next.
Fault: Nothing is displayed on the screen or via an external monitor through VGA cable
Background: The laptop has over heated several times and on one occasion it has shut down completely.
Initial investigation: Tested on battery only and AC (with and without battery) connected and found power led lights green, battery and AC connected green. I press the on button and the fan starts up at a high speed for around 3 secs and then goes off. There is no disc activity light, but I can hear and feel it working - I have tested the hard drive in another machine and it worked fine so I'll rule that out. After about 2 minutes the fan will spin up again for 3 secs and then off again.
Whilst taking the fan out I found a nice lining of dust, dirt and lint which had blocked the air flow almost completely - definitely a cause for the over heating.
I have tested DC voltage across the following caps:
PC71 - 1.23V
PC73 - 0V
PC56 - 3.3V
PC57 - 5.1V
PC103 - 19.5V
Caps PC71 & PC73 (OA4's 220uf 6.3v) wouldn't read in circuit. I took these two out and found high esr values. I didn't have any SMD caps so to test I replaced temporarily with rubycon ZL's - unfortunately this has not fixed the issue.
Any advice greatly appreciated as I am not sure what to test next.
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