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76
Chart 13—Serial Bus Failure
Yes
No
Yes
No
Yes
No
START
Verify that the VRS750
dip switches are set to
normal operation.
Does
TP105 pulse ~5VDC
when the volume button
is pressed?
Does J30-21
pulse to ~0VDC when
the volume button is
pressed?
Check the mobile
to VRS cable.
Is there
continuity between
J30-21 and J20-9 on the
flex cable?
Check and/or
replace U103 and
Q103.
Check and/or
replace the
transceiver.
Replace the flex
cable.
Verify that J30-20
(boot control) is
~3.3VDC.
SERIAL BUS FAILURE
Summary of Contents for VRS750
Page 1: ...1 VRS 750 Vehicular Repeater System Detailed Service Manual ...
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Page 40: ...28 Notes ...
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