HDMI broke on amp and projector simultaneously - what could have caused this?!


Standard Member
So I've got a Denon X6700 receiver hooked up to a Samsung 65" TV on the main output and an Optoma UHD60 4K projector on the sub out, been running for about 6 months with no issues at all. The amp is only 6 months old, but the projector is 2.5 years old now. I've never had any issues with the projector at all, but a few weeks ago I noticed when using HEOS to turn on the amp, no music would output and there would be no speaker symbols on the display, I'd have to reboot the amp every time to get it to work. If the amp was switched on first and I then opened the HEOS app it worked perfectly, it was only when trying to initiate everything with the app that it didn't work. Maybe unrelated, but thought it was worth mentioning just in case!

Then last weekend I turned the amp on to watch TV, and there was no sound. No speaker symbols on the display either, but this had never happened before other than with the HEOS issue. I then turned on the TV and saw there was no picture either, and a quick Google search said that these symptoms could well be from a faulty HDMI board in the receiver. However, where this gets more intriguing is that after swapping back to my old receiver so I could still watch TV, I turned on the projector and that didn't work either, just saying "No signal".... So I did some investigation, tried hooking up a Google Chromecast directly to the projector and still nothing, but when trying the other HDMI input on there I was able to get a picture from both sources, so essentially HDMI 2 was broken.

As part of my investigations though, I also tried another HDMI cable from the receiver to projector and this one worked using HDMI 1 input, when my other fibre optic cable didn't work, so this was ALSO broken! Just to confirm, I also checked the fibre cable between Sky Q and the receiver, and it's definitely broken, so what on earth could have caused this?

It's too much of a coincidence for the receiver, cable and projector to all break on the same day unless it was related, but I really don't know what can be to blame for this. As it's a fibre cable too, surely there's no direct electrical connection between the receiver and projector that perhaps a spike could have fried all 3? If you had any input on this I'd love to hear it!


Distinguished Member
AVForums Sponsor
With HDMI cable, sadly they can just fail. It's one reason why I always say, if you are installing a projector system, then ensure you can always retrieve it by not fastening it in which will enable you to pull the failed cable like a drawstring once the new cable is attached. HDMI cables can fail when hot swapping when any of the devices its connected to is still powered on when unplugging as they can create a small arc (which I actually seen), most of the time, you will get away with it, but there is an element of chance with it

With what you have mentioned, it does sound like you've had some kind of spike in the room which could have caused these issue and that will certainly be a little harder to find unless its obvious


Distinguished Member
A short circuit, lightning strike or anything where an electrical charge would be conveyed from one of the 2 devices along the HDMI cable to the other device. Hotplugging HDMI devices can also cause damage despite the fact HDMI org suggesting HDMI is hot plugable.

HEOS has nothing at all todo with HDMI.

Maybe something shorted out onboard the PJ and an ekectrical charge could have then been conveyed from the PJ back to the AVR along the HDMI cable between them?

Fibre HDMI cables have active circuitry so this too suggests that there may have been some kind of electrical discharge aling that cable causing it damage if it also no longer works? Note that most fibre cables are in fact hybrod cables, meaning that they have both conventional copper wiring alongside the fibre optic element of them. It may have been this copper cabling that conveyed an electrical charge from one device to the other as opposed to the fibre opticas of that cable. The copper wires are there to fascilitate functions associated with HDMI CEC and or ARC.
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Distinguished Member
As it's a fibre cable too, surely there's no direct electrical connection between the receiver and projector

The vast majority of "Fibre" cables I've seen are labelled as Hybrid Fibre which means both an optical cable and some wires so that's not necessarily the case.


Distinguished Member
After sorting out the issues may I suggest purchasing a surge protector to prevent a recurrence? One that handles the full set of AV connections involving the outside world costs about £50.


Standard Member
I've got a surge protector on the system in the lounge already, and a second one on the AV rack in the garage too - I was never sure how good they are though, so if this was a lightning strike/spike then I'm guessing it should have stopped it?

Optoma have confirmed faulty HDMI board and £270 for a replacement, still waiting to hear from Denon on the receiver and it went in a week before the projector did!

Joe Fernand

Distinguished Member
AVForums Sponsor
if this was a lightning strike/spike then I'm guessing it should have stopped it?’ - not a chance that a ‘surge protector strip’ is ever going to deal with lighting, read the small print of the ‘guarantee’ you will see it would cost you thousands of £/$ to be protected against lighting and in reality your surge protector would plan a very small part in that protection.

Another big issue with surge protectors is that they have to sacrifice themselves and only the decent ones will then stop passing power and indicate they need replaced.

Lighting often enters an AV system via a Sat dish or aerial and can then jump from device to device via HDMI cables.


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