I will never tip for them to fix a problem like that. I believe that encourages them to have things not function, play the odds, I'll call downstairs, and they can send somebody to fix it and maybe get a few dollars.
When I check out, the TV mysteriously stops working again and the game starts again for the next person.
There's a fine line to me in hotels for who to tip and not. I have a problem with housekeeping leaving envelopes with their names on them if I didn't leave money out the first night, then a day later leaving a bright green printed sheet with housekeeping tipping guidelines on it.
I'll tip for service above and beyond, but I won't reward you for doing your job.