Service manual

Revision 2/18/05 3 - 49
Hardware Description
Auditory Stimulators
The Auditory Stimulator Least Replaceable Units are:
• Endeavor CR Base Unit
• VikingQuest Base Unit
• VikingSelect SC-1 Stimulus Controller and AU-1
Auditory Stimulator
• Transducers
- Unshielded TDH-39
- Shielded TDH-39
- TIP 300 Tubal Inserts
- Bone Vibrator
Base Units
For the Endeavor CR and the VikingQuest, an auditory
stimulus board within the Base Unit generates the
clicks, tones, and noise masking levels for the Endeavor
CR. The auditory stimulus generator requires no
adjustment or maintenance.
The Base Unit is an LRU, and must be replaced if you
determine that a fault lies within this unit.
VikingSelect
On the VikingSelect, the auditory stimulus is generated
by a digital signal processor on the SC-1 Stimulus
Controller. The digital form of the auditory stimulus
signal is routed to the AU-1 Auditory Stimulator
module where it is converted to analog form, attenuated,
and delivered to the transducer.
Auditory Transducers
The auditory transducers convert the electrical signal
from the auditory stimulator to sound. VIASYS
provides a variety of transducers to meet specific
customer needs.
The transducers are LRUs and have no replaceable
parts. They require no adjustment, but should be kept
clean to extend their useful lifetimes.
TDH-39 Headphones
The TDH-39 are aural headphones used to present an
auditory stimulus to the patient.
TIP 300 Tubal Inserts
The TIP 300 Tubal Inserts are an alternative to the
headphones. The transducers for the tubal inserts are
hung from the neck, away from the recording
electrodes. Sound is delivered to each ear through a
plastic tube, to an insert placed in the ear canal. The
distance between the transducers and recording
electrodes eliminates the stimulus artifact inherent with
headphone transducers.
Bone Vibrator
The Bone Vibrator delivers an auditory stimulus
through the skull, bypassing the eardrum to stimulate
the cochlea.
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Shielded
Unshielded