I have TCL 55S423TCAA and neither IR remotes will work the TV, and I know the remotes are working fine. The TV is not acknowledging any IR signals and the IR sensor is not being blocked and nothing has changed in the environment. The TV does respond to phone app when I installed one and I checked settings and updates, so everything is fine there. I am electronic savy and know how to repair electronics down to board level repair. Anyone have suggestions, is it a module inside the TV that can be easily replaced or any schematics. I don't know if the IR detector has gone bad or the circuit it is tied to.
I've taken several TVs apart over the years and the IR receiver is generally located on a tiny circuit board with the switches (or the one and only switch on newer TVs) and power light/LED. You may be able to get a part number off of it and find a replacement on ebay or you can try to just replace the IR photodiode (receiver) that's a small 2-pin device. You can probably find them on Amazon or for pennies from China. If you're really ambitious, you could even test the one that's in there now.
I'm having this same issue. Is a repair the only option? Will resetting the tv to factory settings help?
@Dip9, there's no way to say for sure what the problem is, but if you've verified the remote is transmitting using a digital camera and the TV doesn't respond then it could be the IR receiver. A factory reset most likely won't help and will probably make the situation worse since you need a working physical remote to set up the TV. If the TV is still connected to your network, you can use the Roku mobile app as a remote. You can also get a Roku voice remote, but you have to pair it by using the mobile app as a remote to get to the pairing routine or factory reset the TV.
Roku Mobile App - Free for iOS® or Android™ | Roku