I use a DIY universal remote made from an Arduino using the IRremote library that allows me to send a code like:

4550,4450,650,1600,650,1600,650,1600,650,500,600,500,650,500,600,500,650,500,650,1600,600,1650,600,1650,600,500,650,500,600,550,600,500,650,500,600,500,650,1600,650,500,600,500,650,500,600,500,650,500,650,500,600,1600,650,500,650,1600,650,1600,600,1650,600,1650,600,1650,600,1600,650

to an infrared emitter. That code would power off my Samsun TV. I have that process setup for my TV, Insignia receiver, and my Mac Mini and it works great on all of them. I also have a DirecTV model HR24-100 that uses a DirectTV remote RC65X which I can not get to work. The IRremote library for the Arduino also has a process for decoding infrared signals which I used on all of the devices. The DirecTV buttons get decoded and seem to intermittently work and then will stop all together. Decoding the same buttons on the DirecTV remote will then produce a different code.

Does anybody have any insight on why the DirecTV remote will produce different output over time?