I would try a new sbc (single board controller) pwb.
Dear all,
I have one problem of my WC-7535. The printer status shows “The Machine is not available.”
“Reset The Machine”
Turn the power to the machine OFF and Wait 2 minute(s)
I load the software from USB flash drive (Regular AltBoot, upgrade and FORCED_UPGRADE) but I face same problem. When I tried to load software it take to 25-30 min but “Data Encryption/Decryption” take above 2 hour. I also changed the HDD but same problem.