If you use neohacker as stated go to the power
button
on the proper page for your tv settings and go
to
Actions, then to Learned IR, then to Duration.
You can change the duration of the pulse that
is set
normally to 0;0 to a longer length.
Try 0;5 to start and then try increasing as necessary.
Please let us know what worked for you so to help
other people in the same situation.
Good Luck.