hi
i'm facing a very weird issue with a DVD device...
by mistake i've damaged the power supply from a dvd player, replacing some components i've managed
to make work again, but the internal dvd device refuses to power up.
there's an LM317T on the power supply board, following the rails they go to the power connector for the
dvd but when i'm connecting it, the LM317T gets quite hot (120c) and the dvd doesn't spin, so i've tried to
replace the LM317T in case it also got damaged, but nothing happend.
i've measured the LM317T without load and it seems it is regulated at 11.45V also if i connect
something else, it works just fine!! without getting hot, also noticed the regulating resistors are 220ohm
and 1.8k so i guess the output i've measured it is quite ok.
now if i use an external power supply for the internal dvd it starts to spin and everything works perfect!
so then the internal dvd isn't damaged, but what happens when i'm connecting the dvd power connector
to the internal power supply?!
checking the label of the dvd it says that it needs 5A for the 12v rail and 1A for the 5v rail and that probably
explains why the LM317T (TO-220) gets so hot! but how on earth it worked all this time and what should
i do to repair it?!!
thanks in advance if anybody is willing to help!!!
i'm facing a very weird issue with a DVD device...
by mistake i've damaged the power supply from a dvd player, replacing some components i've managed
to make work again, but the internal dvd device refuses to power up.
there's an LM317T on the power supply board, following the rails they go to the power connector for the
dvd but when i'm connecting it, the LM317T gets quite hot (120c) and the dvd doesn't spin, so i've tried to
replace the LM317T in case it also got damaged, but nothing happend.
i've measured the LM317T without load and it seems it is regulated at 11.45V also if i connect
something else, it works just fine!! without getting hot, also noticed the regulating resistors are 220ohm
and 1.8k so i guess the output i've measured it is quite ok.
now if i use an external power supply for the internal dvd it starts to spin and everything works perfect!
so then the internal dvd isn't damaged, but what happens when i'm connecting the dvd power connector
to the internal power supply?!
checking the label of the dvd it says that it needs 5A for the 12v rail and 1A for the 5v rail and that probably
explains why the LM317T (TO-220) gets so hot! but how on earth it worked all this time and what should
i do to repair it?!!
thanks in advance if anybody is willing to help!!!