No Display - IC changed, HDD good, HDMI good

Hi Everyone! Long time watcher of Tronicsfix, first time using the forums.

I’ve been doing a bit of Xbox repair through quarantine and I’ve had a lot of success, but I have a few that are beating me and wondered if the forum had any input.

I have 4 boards, all power on with a chime and stay on. Test SSD is known good, HDMI ports on all look physically good and all pins are solid. I’ve checked against a known good, working console board and I can’t see any missing components. I’ve checked all caps for shorts and everything looks good.

I’ve replaced the retimer IC on each one, with the same results - At the point where a picture would usually show, the monitor will wake up but then go back to sleep without showing anything. I’m fairly sure I’ve got the retimer on properly - I’ve done a number of others which have been fine, and it all looks good under the scope. EMI filters all have continuity through them.

Does anyone have any wisdom? I’m at my wits end!