Lost Channels!!!!!!!

[Muhammad Irfan]

I have a Sony Trintron KV-2193MF1. It had a bit of problem which vertical balance & while adjusting that I can`t remember what wrong I did that when I finished correcting that I ended up having channels from 0-79 but previously it had channels from 0-99.
I guess I might have accidently altered the values in the service menu.
Someone please advice me how to fix it or still better if anyone provide me with its service manual so that I can restore all the values to the factory defaults.