Have a magnavox sdtv tuner and a radioshack 3-in-one remote cat No. 15-2143 how do I program it?

First open the back of the remote and take out the batteries. There should be a sticker inside with different serial numbers and codes on it. You are looking for a "CL" number. It will be either a 3, 4 or a 5. This is the generation of remote you have and the remote codes listed will only work on these CL generations. Refit the batteries and back cover.
Go to the website below and it tells you what the codes are and how to use them to activate your remote control. You will need to scroll down the page until you get to where the Magnavox codes are listed. Magnavox has 11 codes listed and you might have to try all of them.

https://www.directutor.com/program-ge-universal-remote#ge%20universal%20remote%20codes

To my knowledge that remote is not externally programmable.

You need to input the Magnavox remote codes until you find one that works, or you can use the "code search" function of the remote

program a magnavox sdtv tuner https://electrohelponline.blogspot.ca/ http://www.remotecodelist.com/ Codes for Universal Remotes How to Program Universal Remote

Find the owner's manual for the universal remote (you may have to get the pdf version online) and look up the model number for the tuner in the list of supported devices. The manual will have instructions for entering the code for that model number into the remote.

Set-up (Programming) procedure is too much to type in here, and is not practical and it will differ brand-to-brand remote controls. If you wish to get more; check the site linked here. It has set-up code list & set-up procedure to many popular brand remote controls. Pull up older posts.
http://electrohelponline.blogspot.com/
http://remotesearch.blogspot.com/

i need the codes for rca rcr6473r i have a go.video vcr dvd combo...

go to www. fitness.manualsonline.com or www.remotecodelist.com

God bless you

try what it says here

http://support.radioshack.com/support_video/doc7/7967.htm

if this info helped please vote for me

Need code for the remote