I'm not really "certified" to work on Sharp equipment but from what I understand their Service Mode is called "Simulation Mode".
To get into Simulation Mode you'll want to do the following:
1) Copy mode key ON → Program key ON → Asterisk (*) key ON
→ CLEAR key ON → Asterisk (*) key ON → Ready for input of
a main code of simulation
2) Entering a main code with the 10-key → START key ON
3) Entering a sub code with the 10-key → START key ON
4) Select an item with the scroll key and the item key.
5) The machine enters the mode corresponding to the selected
Press START key or EXECUTE key to start the simulation
To cancel the current simulation mode or to change the main
code and the sub code, press the user setup key.
∗ Canceling the simulation mode to return to the normal mode
1) Press CA key.
You can download the service manual here: http://businessneedz.com/Info/?p=169
Perhaps another member more familiar with the Sharp equipment can be of more assistance.