Solved! Alternating HDMI ports not working...?

[Whisper]

Hi all, been a while since I've posted here on AT, but figured I'd come back to probe the collective wisdom.

We have a 65" TCL Roku TV hooked up to our Cox Contour TV box. A couple months back, our HDMI 1 port stopped working (i.e., reports no signal). As the same thing (with the same Contour box) had previously happened to all 4 ports simultaneously on our prior Samnsung TV, we were thinking the Cox box, a thunder storm, or something else had fried the port. The 2nd and 3rd ports on the TCL still worked fine.

Fast forward to a week or two ago, and HDMI 1 suddenly started working again (we didn't change anything that we know of) but HDMI 2 was now out. That's where we stand now.

So I'm wondering what exactly happened. Seems odd to me that the non-working port would suddenly alternate like that, but I'm admittedly woefully under-informed about TVs. We tried resetting to factory settings back when HDMI 1 wasn't working, but that didn't fix anything. I honestly have no idea why HDMI 1 just came back on by itself.

Any thoughts on what could be going on?

 

[Fallen Kell]

Could be something with your TVs power supply and or the power delivery to the hdmi ports on your board. I believe each port has to supply a minimum of 50mA of 5V. It might also be a failing MUX switch on your board which controls the switching between HDMI ports, or any number of possible shared components on the HDMI circuit (all of which would be board specific to your TV and very hard to diagnose without a schematic). You should search for the “service manual” and “board diagram” for your exact model number (ie TCL 65S405, or 65S425, 65R617, 65S401, etc., etc.). You will need the exact model number as you can see there are lots of 65 inch TCL Roku TVs and each will have a different service manual.

The service manual typically has lots of good troubleshooting information in it. Usually with multiple pages of items like “there is no sound even though the volume is turned up and the TV is not muted”. Or “HDMI input does not work”.... Some combine the board diagrams with the service manual so that you can see/find the component that they tell you to test/check. You will need a multimeter at a minimum to check most things yourself. Otherwise I suggest looking up and finding a decent local TV repair store near you and see if they can diagnose the issue (some will charge for that, others might only charge if you don’t have them perform repair work but that is all different from store to store).

 

[JEDIYoda]

sounds to me like you have a case of HDMI gremlins......

 

[Whisper]

Hah, with my luck, it probably is gremlins.

Thanks for the input, I'll try to track down the service manual and board diagram.

As an update, the cable was going in and out while plugged in (e.g., signal going black or to static), so I tried plugging my Playstation into port 1. TV didn't recognize any input. Plugged the PS into port 3 and it worked fine. Plugged the cable back in to port 1 and it also showed up fine.

I'm somehow even more confused.