I have a very old TV in our dorm. It's a Philips early version of color TV, very early I guess it's probably one of those first generation of color TVs without remotes. Recently it just stopped making sound, well not completely, after about 2 hours on average the sound came back again but it's still quite annoying and I'm just here to ask is there any way to fix the problem or I have to open it 2 hours before the program that I want to watch?

Many thanks

I could be a number of things, but based on the age of the TV, you may just want to save $20 bucks and check out craigslist or a for sale site. There are hundreds of cheap used TV's out there. Good luck.

If safe working in on a TV and understand the dangerous High Voltages.
I would follow the speaker wires to the circuit board and first visually look carefully for a cold or fine crack around solder connection, remove old solder, and resolder. Don't overheat.
If there is a headphone jack, make sure it is making contact to allow speakers to have good connection. Tapping or pressure on parts may reveal component involved, then check connection.