Re: Toshiba 40E200U1 turn ON but no backlight, no video
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Attached Files
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
https://www.badcaps.net/forum/attach...9&d=1472859377
OK, check the DCV on the Collector (C) of that Transistor Q801 with ref to the primary circuit GND.
I exepct it to be around 18~20VDC range, I see it now that is the switched Transistor for supplying Vs for the IC.
The AC Voltage is generated by the AUX winding of the STBY power transformer, it is rectified by D803 and fed through R805 and is filtered by C802 and then fed to the Collector of Q801. This AUX Voltage is also the running Voltage for the STBY SMPS IC.
Q801 is turned on by OPTO PC902 (you can see it is bias ON through R810 when OPTO is turned on),Last edited by budm; 09-02-2016, 08:20 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
Switched Vs circuit.
BTW, did you try having everything all hooked up but not the LVDS cables connected to see if the 12V/24V will return?Attached FilesLast edited by budm; 09-02-2016, 10:47 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
Q801 collector: 28v, with lvds cable disconnected 12v/24v not presentComment
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
So the switched Transistor is getting the input Voltage but no output on the EMITTER leg.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
Yes, 0v on emitter legComment
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
It seems as though ACD comes from the main board and is not required to power up the power supply secondary voltages according to the following link. It says to jumper 5V stby to PS_On and also 5V stby to BL_ON. The 12V and 24V should come up as well as the backlights. I assume this is with the main board disconnected from the power supply.
https://www.badcaps.net/forum/showth...light=40E200U1Willing to help but I'm no expert.Comment
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
I already did, 12v /24v not presentComment
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
Need to measure DCV between the two legs on the cold side of OPTO PC902, and between the two legs on the HOT side OPTO PC902. when PS-ON is present.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: Toshiba 40E200U1 turn ON but no backlight, no video
I will do that tomorrow in the morning
Thanks for replyComment
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Hi all,
Ok so I have this beautiful un55h8000 samsung tv with sound but no video nor backlight. When turning the set on the red light blinks 5 times.
The screen shows no damage and backlight turns on when I disconnect the power supply from the main board. The tcon board only has 2 out of 3 leds on.
I came across this page and followed the different steps: https://techhometravel.com/samsung-u...ight-no-video/
- Unplugging the main board cable at the power supply >>> backlights came on.
- BLU_ON signal from the
- Unplugging the main board cable at the power supply >>> backlights came on.
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