To check that the TX IR LED is active (transmitting) you can use the front camera on a iPhone or iPad.
/steffen
I’m joining the choir of Gold members showing as Bronze member in the forum.
Quality Dream Audio make replacement glass panels for 3500/4500 system.
I’ve used them before.
https://www.quality-dream-audio.co.uk/replacment-glass-panels/replacement-glass-panel.html