Sony DVP-F21 Service Manual page 71

3. SYSTEM CONTROL - IF CON serial
communication
The IF CON and SYSTEM CONTROL are usually performing
both-directions communication in a cycle of 24 ms. This mode
checks in simple whether this communication is performed
normally. When "NOTHING" is displayed and the character
[VCR] [DVD] [CD]
portion of , and has gone out on the left side
of the display, this state means that communication with
SYSTEM CONTROL is performed normally. If the character
portion is lit up, this state means the communication is not
performed correctly. After the test mode is executed (until
initialization of the MB-89 board is completed), communication
is not performed for several seconds. Although the character
portion may light up in these intervals, but this is normal.
4. Fluorescent display tube lighting check
Fluorescent display tube lighting check can also be performed
roughly by automatic mode. But when checking in detail, use this
mode.
[STOP] [PLAY]
When and buttons are pressed simultaneously,
all segments of the fluorescent display are turned on. The
button of the remote commander can also turn on all segments.
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