Acer aspire 4741z
Posted: Wed Apr 06, 2016 2:47 pm
Case study . Acer aspire 4741z no didplay
PSU reading is .45 amps with and witout ram .
Checked and found 3d3v_S0 and 5V_S0 are low At mosfet u55 and u56. no shorting found but out put of these fets is low .jumpered the drain source of these mosfets and got display every thing worked fine . Drain of these mosfets has healty voltages no drop but gates of these mosfets are low which is feed by a p-channel fet q47. It's source voltage is low which is connected to 19v line through 10k resister r583 . And this r583 causing low input to q47 . R583 10k Replaced with 1k and it improved the source voltages as well drain voltage up to 9.5V which is connected to the gates of u55 and u56 and it is enough to oprate these mosfets and lapi worked fine .
[ Post made via Android ]
PSU reading is .45 amps with and witout ram .
Checked and found 3d3v_S0 and 5V_S0 are low At mosfet u55 and u56. no shorting found but out put of these fets is low .jumpered the drain source of these mosfets and got display every thing worked fine . Drain of these mosfets has healty voltages no drop but gates of these mosfets are low which is feed by a p-channel fet q47. It's source voltage is low which is connected to 19v line through 10k resister r583 . And this r583 causing low input to q47 . R583 10k Replaced with 1k and it improved the source voltages as well drain voltage up to 9.5V which is connected to the gates of u55 and u56 and it is enough to oprate these mosfets and lapi worked fine .
[ Post made via Android ]