Help HDMI no longer works

[Didjit]

I have a USB-C to HDMI connector for my Galaxy S8. It used to work fine, but now my phone won't output HDMI at all. My partner's phone - same phone model, same OS version - works fine. I've made sure my display settings match his, I've turned off developer mode, I've rebooted, but none of this helps.
Any other ideas?

 

[mikedt]

I have a USB-C to HDMI connector for my Galaxy S8. It used to work fine, but now my phone won't output HDMI at all. My partner's phone - same phone model, same OS version - works fine. I've made sure my display settings match his, I've turned off developer mode, I've rebooted, but none of this helps.
Any other ideas?

Given what you've tried, sounds like it could be a hardware problem in the phone itself, Samsung service required. Is it still under warranty?

 

[Shotgun84]

Hi. One thing that caught my eye there was that you turned off developer options. That shouldn't be visible with a stock phone. Have you rooted and flashed some custom firmware?

 

[Kevin-B]

Hi. One thing that caught my eye there was that you turned off developer options. That shouldn't be visible with a stock phone. Have you rooted and flashed some custom firmware?

Shotgun84: I'm not sure I agree with your suggestion. I have a stock, non-rooted phone. [I rely too much on my phone to fool with rooting, after some youthful experimentation in the past!] I can can turn on developer options without rooting by doing the standard steps:
Settings > About Phone > Software Information > click on "build number" 7 times, and developer options are enabled. I can then turn them off, as OP says. Rooting was never involved.
Or perhaps I'm misunderstanding something?

 

[Shotgun84]

Shotgun84: I'm not sure I agree with your suggestion. I have a stock, non-rooted phone. [I rely too much on my phone to fool with rooting, after some youthful experimentation in the past!] I can can turn on developer options without rooting by doing the standard steps:
Settings > About Phone > Software Information > click on "build number" 7 times, and developer options are enabled. I can then turn them off, as OP says. Rooting was never involved.
Or perhaps I'm misunderstanding something?

Yeah I know you can turn them on without rooting but unless you're a developer there's no reason to turn them on unless you're going to root your phone. Hence the suspicion the phone's rooted since developer options were on

 

[Didjit]

No, the phone is not rooted. I forget why I turned on developer mode. Probably just to get at a setting.

 

[Didjit]

Given what you've tried, sounds like it could be a hardware problem in the phone itself, Samsung service required. Is it still under warranty?

I'm sure I'm out of warranty. Also, it seems unlikely to me that just this one feature would break. And of our to phones mine is the much better cared-for.

 

[mikedt]

I think there's a specific HDMI chip that enables this feature on devices. And if that chip is blown, no HDMI video out. I've seen failed HDMI on laptops and tablets, where the internal screens are still working. Semiconductors can still fail no matter how well a device is cared for.