Specifications

Troubleshooting Symptom Charts/Audio (750AV only) - 9
Audio (750AV only)
The symptoms associated with a defective sound enclosure are
relatively easy to diagnose. Following are typical symptoms of a
defective audio system. However, some of these symptoms can also
be caused by defective speakers, the built-in microphone, and
connectors or cables that plug into the sound enclosure.
• No sound left/right channel
• No recording capability (internal/external microphone)
• No volume/bass/treble control
• Sound distortion
• No gain control (line in and external microphone)
• Loud popping sounds
• Headphones have no sound
Miscellaneous
Microphone doesn’t
work
1 Without removing rear housing, disconnect microphone from
bezel of AppleVision 750AV Display.
2 Connect microphone to known-good AppleVision 750AV
Display to verify whether it works.
• If microphone doesn’t work, replace it. Because
microphone cable might also be damaged, go to the next
step to check it.
• If microphone works, check microphone cable (as
described in the next step).
3 With microphone disconnected, use a DC voltmeter to check
contacts on microphone connector that is secured inside
monitor bezel. The voltmeter should measure 8 volts DC.
4 If voltmeter reads 0 VDC, remove sound enclosure, connect
extension cables to head unit, and measure voltage at the
microphone connector (BA10) on sound board.
• If voltmeter measures 8 volts DC, replace microphone
cable
• If voltmeter measures 0 VDC on sound board at BA10,
replace sound board
Thin horizontal lines
on screen
Displays larger than 15 inches with tron-style CRTs typically
have two wires, each about one-quarter to one-third of the way
from the top and bottom of the display image. These supporting
wires, which are thinner than a human hair, stabilize the
aperture grill against shocks. The lines are common to all tron-
style displays and are not screen defects. They cannot be adjusted
out or eliminated by repairing or replacing display modules.