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joao2004
Joined: 24 Jul 2008
Posts: 4
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 Posted: Sun Feb 19, 2012 4:18 pm Post subject: [SOLVED] LCD samsung LE40A656 - no picture, no osd |
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Hi, i have an lcd tv samsung LE40A656 with the following fault:
tv turns on ok, but no picture, no OSD ! back-light is working and psu is ok
red led blinks 5 times at switch on
tv is about 3/4 year old but it only has a few hours of service.
any help?
Last edited by joao2004 on Wed Feb 22, 2012 4:29 pm; edited 2 times in total |
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Guest
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| Posted: Tue Feb 21, 2012 12:20 am Post subject: |
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I can't find a fault listed the same as you're describing. The only one similar refers to the screen going black after a while, and the advice is to resolder joints on PSU. Generally capacitors in the PSU seem to cause a variety of symptoms too.
Check all cables are making good contact too.
E-mail me at: "james q b 2001 at yahoo dot co dot uk" (remove spaces and replace words - dot, at - with corresponding symbols as required) if you want the service manual for this set. You'll be able to check voltages are correct, etc., then, as well as further fault finding. |
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chappers
Joined: 21 Feb 2012
Posts: 3
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joao2004
Joined: 24 Jul 2008
Posts: 4
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| Posted: Tue Feb 21, 2012 10:27 am Post subject: |
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Thank's for the tip...i will try that
There's no OSD at all !!! |
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joao2004
Joined: 24 Jul 2008
Posts: 4
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| Posted: Wed Feb 22, 2012 12:15 am Post subject: |
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I was unable to get mtktool to communicate with the tv... but i tried to update firmware thru usb flash drive and i think it updated (after ~2min tv shut down) but still the same...
i checked that audio works fine...
checking voltages, there is something strange with the +33v (to tuner). At power up there is 33v, but after ~5 sec it goes down to ~13v. if i keep changing channel it varies between ~12v to ~23v.
Also B9v seems to have some ripple (~0.4Vpp)
I maybe try to replace the TCON board... |
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joao2004
Joined: 24 Jul 2008
Posts: 4
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| Posted: Wed Feb 22, 2012 4:27 pm Post subject: |
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Problem Solved... it was a fault at TCON board
later will post some details. |
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dhoshi21
Joined: 15 May 2013
Posts: 1
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Guest
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| Posted: Wed May 15, 2013 11:59 am Post subject: |
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| dhoshi21 wrote: | | joao2004 I am waiting detail |
Sorry... i forgot about this post
it was a faulty diode (open or short, can't remember...) near a voltage converter chip (3.3v i think) |
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Guest
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| Posted: Sun Apr 20, 2014 9:16 pm Post subject: |
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| ACK do you know which diode it was , have same problem |
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