A7 is a very early version of the Raritan
Atlantes, mfr'd 1991-'96. There is still a rebuild
kit available for it...part # ATDISRK
If it needs more than a rebuild
kit, you'll need to have a chat with Raritan tech support: Mac McCoy in their Ft. Lauderdale plant would be my go-to guy for a toilet
that old...his phone
number is 954-525-0378
"If you can't explain it to a six year old, you don't completely understand it yourself."