Issues with a HDMI switcher between a Copmuter and Projector

[BrendanvB]

Hi Everyone,
I am running a computer to a projector and converting HDMI to SDI and then back again at the source because of the distance (30m)

The computer connects to the projector no issue and shows the image we desire so the cabling and converters are operational.
For the space I need a way to have at least 2 HDMI inputs and would prefer not to be plugging/unplugging all the time. As soon as I introduce a switch or even a 5.1 amplifier with HDCP and UHD 4K etc the projector shows no image, just a black screen.

converters are Blackmagic mini converters
Amp is a Denon AVR-X520BT
HDMI 2.0 at every point

Would love some help on at least identifying the issue.

 

[americanaudiophile]

I would suggest you try connecting the PC and receiver without the converters. You can move the PC, receiver and projector close together for the trial.
If it works then a good quality powered HDMI cable may be your solution. They do come in 30m lengths.
There are also HDMI over CAT6, wireless HDMI and fiber optic solutions available.
If not then you may need to use a pro quality switch and perhaps CAT6 instead of SDI converters.