last man on earth on tape?
buy 2 machines used and now have parts( NO OTHER WAY!!!)
there is no books AT SONY or support now. it ended long ago\ 1987 ,35 long years ago/.
the free shop manual is here, 155pages
I would try and unplug the TV and all of the attachments that are connected to your TV and wait for a few minutes to plug everything back in again and see if that fixes the problem. It could be an issue with your TV's mainboard or a power supply issue.
Make sure the MUTE function has not been activated. Try turning up the volume level. Check that there are no headphones connected. Check if the issue also occurs to other device connected to the TV.
https://www.sony.com/electronics/support/articles/00023449
5 red flashes is a bad panel connection or internal panel short, very carefully take the panel connectors off and reseat them and see if that helps, unfortunately you may have a bad panel.
Probable damage to the main board caused by lightening/storm activity.
It is possibly not ever going to be a successful repair.
Being LCD it is older technology and spares will be few and far between, not to mention expensive.
need service manual to determine the fault code usually by counting the blinks normally the blink should pause to let you know the count the look at the symptom on manual.
This problem is often caused by the tape bunching up underneath the flap. Press down on the small release button on the side of the VCR machine and then lift up on the flap.
I would read the part number on the STR and using the gargler (google) get the data on it.
The service manual is the chassis number/type not the model number.