Sony KV-21JSR1 symptom: stretched video

[P990i]

Good day again...sir I had a sony tv that the video is stretched wide horizontaly on both the upper and lower portions...what seem to be the problem with this? what am I going to check? what could be the possible defect of this tv? can this be fix thru the service mode? what are the procedures to enter for the service mode? any help pls....thank you and God bless....