After replacing my TV, I can’t get my blu ray player to properly play. It’s driving me nuts and I’d really like to avoid buying new stuff.

Here’s the setup that previously worked:

• An old Samsung plasma TV to display stuff.
• A fire tv stick to stream stuff.
• A Teufel Impaq 3000 AV receiver with a 5.1 speaker system that unfortunately refuses to directly play back blu ray discs since it overheated brutally before I realised the fan was broken.
• A Sony BDP-S370 that we use to play back blu rays and DVDs.
• A Sonos connect box attached to the teufel as well, but that doesn’t really matter.

I attached the blu ray disc player to one of the TV’s HDMI inputs and the AV receiver’s digital coax input. While the TV had an optical out, using that to get the audio channel to the receiver resulted in loss of quality (I know it’s all digital, but the TV seemed to mess with the audio before sending it out), so the coax cable helped with that. That worked well. Until I replaced the TV.

Current setup is essentially the same as before, except the fire tv stick got removed and we replace the old Samsung plasma tv with a

• Sharp 55GL4260E.

All hate for smart devices aside, the primary use case of streaming from German public broadcast “mediathek” services, netflix and prime works well so far and we no longer have a messed up glass front, which is a big plus. However, I can’t get the blu ray player to work properly. Essentially, I have tried two approaches to connect the devices.

• As previously, bdp to TV via HDMI. That doesn’t work. Like, at all. The TV doesn’t show anything unless I force the bdp to only output SD signals, at which point the TV at least shows something, but the image then is an artifact-ridden mess of purple weirdness. Searching for that issue leads me nowhere, except some very old forums with replies that are 90% clueless and some indicating it might be an issue with the devices being unable to perform their HDCP handshake. Unfortunately, I didn’t take any pictures, but there are some websites that show similar issues (albeit usually at least at full resolution). I tried several different HDMI cables.
• Connecting the bdp via HDMI to the AV receiver (which has two HDMI inputs), which connects to the TV. Oddly enough, this works - so the receiver must do more than just pipiing the signal through (remark here: I used the same cables for this, so the pink-image-issue really can’t be a cable problem). However, after I briefly thought I had solved the problem, I realised that with this setup, the audio and video signals are out of sync. I hate it. Sometimes the video will stutter briefly and the audio will lag a full second or so behind afterwards, but even without that issue, audio and video are almost always slightly out of sync, which is just annoying as hell. I use physical media primarily to have better image and audio quality and this ruins the whole experience.

I’m kind of at a loss. My next step woul be to buy a new blu ray player, but it feels like overkill for something that should still work somehow. Any ideas what I could try?