Grundig COREMAX M1 PROJECT GM, Service Manual

Page: 87 / 98

87 ENGLISH
FAILURE/ERROR ANALYSES
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Sound available but no picture, and back-lights not illuminated
In the cases where audio is available yet the
back-lights are not lit, first of all, check the cable
and connector connections to PSU, TCON
board and panel. After the connection checks
are completed, check whether 12V is present on
the 4th pin of the chassis S100 connector. PSU
must be changed if 12V cannot be measured
on this pin. If 12V voltage is present, check the
13th pin of the S100 connector on the chassis.
If the VBL_CTRL signal is 0V on the 13th pin,
it indicates that there is a problem originating
from software or IC. If the voltage measured on
this pin is 0V, for test purposes connect 3.3V to
the S100 connector of the chassis PSU cable
which is located on the chassis side. If the TV
does not operate, then there may be a problem
originating from LED or driver. First replace the
LED driver (if any) circuit then the panel if the
problem persists. If the TV operates, increase the
backlit to the maximum and install a different
version of software and try again. To make sure
that system works, turn back light down to the
lowest level and check. If no problem occurs,
submit TV.