Display Contrast; Key Tone - Casio PV-750 Plus Technical Reference Manual

Problem: Nothing appears on the display when power is turned on.
Possible Causes
1. The battery switch on the back of the
unit is set to REPLACE BATTERIES.
2. Battery power is low.
3. Display contrast is too light.

Display Contrast

Problem: Display is totally black.
Possible Cause
Display contrast is too dark.

Key Tone

Problem: The PV unit does not beep when you perform an operation.
Possible Cause
The key tone is turned off.
202
Recommended Actions
1. Slide the battery switch to NORMAL
OPERATION.
2. Replace batteries (page 19).
3. Adjust display contrast (page 177).
Recommended Action
Adjust display contrast (page 177).
Recommended Action
Turn on the key tone (page 175).