Q. I recently got Comcast for the first time and the installer came and set it up. But after he left, I noticed that there was a picture, but no sound on my TV. Is this a glitch with Comcast? How do I fix this? — Greta, Boston.

Greta, I hope the Comcast installer didn’t leave your home before testing both your audio and video, but it sounds (sorry, no pun intended) like that’s what happened!

There are a couple of things you can do to troubleshoot your problem. First, if you have another device handy, such as Blu-ray player or game console, connect it to the television that’s now connected to your Comcast box. We want to determine whether the problem is Comcast or your TV.

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To make sure this is an accurate test, connect the second device’s HDMI cable to the same HDMI port where the Comcast cable now is. For example, if the Comcast box is connected to the HDMI 1 port, unplug it and connect the second device to the HDMI 1 port. We want to see if there’s a problem with that port.

Then, turn on the second device and see if you’re getting sound. If you are not, the problem is your television. If you are getting the sound, the problem is Comcast.

If the problem is your television, try connecting the HDMI cable to another HDMI port. If you’re still having a sound problem, then it’s definitely your television and you’ll need a service call.

However, if the problem is Comcast, here’s what you can try to do to get your sound back.

Hit the Menu button on your Comcast remote control twice. Then click on Audio Setup on the Menu listings on your screen. After that, look at the HDMI sound setting. If it’s OFF, turn it to ON.

Then hit the Menu button again to clear the screen. Your picture and sound should be on at this time. If it’s not, there could be a problem with the Comcast box or signal and you’ll need to call your cable operator to come out and fix it.

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— Phillip Swann