Hello and welcome to justanswer.com my name is XXXXX XXXXX X'm here to help you with your TV problem.
What is the make & model of the remote control that you're using please?
Have you tried any codes already?
Thankyou for your reply,
I checked the manual and saw that there is one code that you didn't' list for your RCA TV so please try 634
Unfortunately there are a finite amount of remote control codes in a remote's database.
What you can try to do is set your Dish Network remote control to scan all the codes contained in the database. This is explained on pg5 of the manual. This can take several minutes and may work as sometimes the remote control receiving board inside a TV has been made by another manufacturer.
If trying every code doesn't work then the only recommendation is to purchase a universal remote and I recommend the Harmony remote which has tens of thousands of codes in in their database. (I don't work for Logitech)
Here is their website