Hitachi 42HDS52A TV, I need to replace the power button, it is broken off and stuck inside the housing

It's time for a new TV Jeff, parts will be almost impossible to find and if you are lucky to find expensive.

There might be a failure on the power supply or horizontal section of the TV even if you see some light inside the TV. Some of the voltages could be missing and that is why the TV fails to power up.
If you know how to use a multimeter, you could check all the fuses from your power supply.
Unplug your TV from the main AC line if you intend to do it yourself.
You will know how much you can do or it might safer to contact a tech.
Let me know if you need further assistance

Most likely the buttons on the tv are stuck or malfunctioning, replacment of the button pannel will solve the issue

Universal remotes need to be coded in to whatever appliance you are wanting it to operate. Check the instructions on what codes to use for your Hitachi. Otherwise look on Ebay. There are hundreds of remotes at reasonable prices or check with Hitachi parts for a genuine remote.

It weighs [110 lbs] Gopakumar Gopalan Google

What is the problem you faces with this TV? Provide more details; please. Gopakumar Gopalan Google

So the lines goes up and down or is it across from side to side, if it's side to side then it's your terminal power board.

Hi,
Lamp light ON means TV needs new lamp as existing lamp is either broken or dead.
Replace lamp in TV, replacement procedure would be written in user manual.
Let me know if you have additional question.
Thanks.

on some TVs, the lights do not turn off so that is not that big of a deal.  If you want to make sure, unplug the TV and then push and hold the power button for about 30 sec.  Then plug the TV back in and that should fix the light if it is stuck. (Pushing the power button wile unplugged will reset the system default!) 

Here is the link for the manual; http://www.hitachi-hk.com.hk/FileManager/EN/UserManual/CTV-C29-RF80SNT(Eng).pdf page 15 towards the bottom - unfortunately you can only remove the child lock with the remote. If you look on the remote (possibly inside the battery compartment) it should have a model number - sorry i had no luck yet finding it out online - let us know that, and we can try and source a new remote for you. Try searching for this remote; DYNATRON MR160 MIRACLE REMOTE CONTROL It is designed to control all hitachi tvs from 1988, including all the hitachi brand specific functions and seems readily available, no link because you will find lots, maybe somewhere close to you. Sorry if bad news; hope it helps :)