Grundig 40VLE630BH Service Manual Download

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TP CHASSIS / TELEVISION

84 September 2011

11. FAILURE/ERROR CODES

11.1. Sound but no picture, and backlight illuminated

In this section, we will basically explain where we need to check if there is "no picture
on TV" even though there are not any problems in the panel inverter. Here, we are
assuming that chassis is generally in good condition as we obtain sound output from
TV.  When  you  cannot  determine  if  the  backlight  is  working  or  not  due  to  the
illumination level in the environment, you are recommended to tap on the TV's front
panel lightly; if the backlight is working, you will notice a slight glowing.

Before  starting  controls  and  repairs,  it  is  crucial  to  analyse  and  comprehend  the
problem  exactly.  In  this  problem,  you  must  make  sure  if  it  is  originated  from  the
utilized  source,  if  it  is  a  cable  connection  error  or  if  utilized  devices  have  any
problems or not.

Then,  particularly  LVDS  cable  on  the  chassis  should  be  checked  for  any
disconnections,  loose  parts,  dislocations,  breaks  or  ruptures.  Likewise,  it  will  be
proper to check cable connections of the panel.

Later, the panel power (VCC_PANEL) supplied to the panel T-CON board over LVDS
cable  should  be  checked  on  L615  position  in  the  chassis.  Panel  supply  for  the
products with TP chassis is 12V.

If this supply is not available on L615, check for 12V on the S605 socket’s pin 11. If
12V  supply  is  not  found  on  S605  socket  although  POWER_SW  signal  exists,  PSU
should  be  replaced.  If  POWER_SW  signal  is  not  available,  main  IC  and  peripheral
components should be checked.

If VCC_PANEL voltage is found in T603 Leg 2 but not found in Leg 3;
T603 and peripheral  components are  checked. When TV  is  “ON”,  a  voltage  around
3.8V occurs on Leg 1 of FET as to be higher than 0V, and supply voltage on Leg 2 is
transferred  to  Leg  3.  If  Leg  1  does  not  have  voltage,  check  "TCON_ON"  signal  on
Leg 8 of R660 resistance. Here, if the voltage is High, it means that panel supply has
not been turned on from the main integrated circuit or software. This signal remains
high  while  the TV  is  going  out of  Stand-By  and  gets  down  to 0V, 1  seconds before
the picture appears on the screen.

If the panel is supplied voltage over LVDS, it is most likely that picture information is
transmitted  as  well.  Even  it  is  not  a  precise  control  method  to  be  used  during
information flow over data lines, the measuring tool detects voltage around 12V DC.
In  this  case,  an  error  is  likely  to  be found  in  panel  side or  100Hz  URSA  processor,
RAM or flash.

If  LVDS  supplies  do  not  have  a  problem  and  LVDS  data  reaches  but  does  not  exit
IC800,  URSA  should  be  checked.  URSA  processor  IC800  and  RAM’s  IC801
VCC1V5  supply  voltage  should  be  checked.  Also,  the  error  may  be  originated  from
IC802 URSA flash or software (URSA.bin).