Turn off Beep on old Magic Chef microwave

Question

Built 1988, part no ACV9ZZM15

Is there a keypad sequence that will turn off the Beep sound? This old microwave is in use in an office next to a conference room. The beep is really loud when making keypad entries... and there are three obnoxious and long beep tones when finished.

Any help for this old machine? It still seems to work fine otherwise.