Audio Input/Output Block Explanation
(See Pages 2
3
and 2
4
)
Audio Input
All inputted audio signals connect directly to IC2201 the main audio and video
switch located on the Video UCOM PCB. When the user selects an audio and video
source the main UCOM (IC1906) sends a serial command to IC2201 for selecting
the proper input source. Note: The only input that does not go through IC2201 is
the Center Channel Input. After proper input selection by IC2201 the right and left
audio signals go to switch IC2202 the (left/right & center) switch. If the user had
selected in the menu to use the set a center channel for all inputs this switch would
move to the lower position. If the switch is in the L,R position the signals pass onto
the preamp IC5502 located on the power supply PCB. The preamp IC provides
input gain control, tone, bass boost, front surround and operates as an electronic
volume control. From the preamp the signals pass onto the power amp IC1101 and
onto the speakers. DC detection is provided prior to the speaker output to prevent
damage to the speakers. This detection will cause the set to shut down. See page 60
and 62 for details.
Audio Output
The audio output jacks on this set can be used as a Fixed or Variable type. When
used as a Fixed type the L,R audio signals from IC2201 simply pass through the
switch IC2203 and the muting circuit than onto the RCA type jacks located on the
back. If the menu has been set to make the output Variable the signals pass through
the preamp and electronic volume control prior to entering switch IC2203.
Monitor/TV Output
If the system mode is set to OFF (the default setting) this output operates the same
as the normal audio output jacks in fixed mode.
If the user selects (System Mode On) from the menu this output sends the signal
from the tuner only.
