No Picture (LED failure)
Depending on the make and model of TV, LED failure can present itself in a couple of ways, I’ve had many Samsungs recently where the failure of just one LED will prevent the TV coming out of standby. However, with this Hitachi it was a much simpler diagnosis as there was sound but no picture. Before dismantling the screen I thought it prudent to check there was voltage leaving the LED driver…there was, so it was certainly an LED problem.
Below is a video showing the method I used to check the individual strips and isolate the faulty LED’s.
As can be seen, there were several failures, these have probably gone one by one over a period of time, but eventually the current sensing in the LED driver will figure there’s something wrong and shut the screen down.
LED replacement is not a simple or straightforward procedure, it probably took three + hours to replace the six that had failed and below is a video of the screen, partially reassembled, to show all LED’s working.
As a footnote to all this I should say that all manufacturers consider a screen to be a non repairable item, the term ‘screen’ would include the backlights…they do not provide LED strips as replacement parts. I should also note that this TV was only fifteen months old, despite that, Argos did not want to know, in their eyes it should be skipped. Companies like Argos and Currys, and all the manufacturers must hate it that engineers like myself have found a way around this.
I’m seeing more and more LED backlight failures from a variety of manufacturers, but don’t think this is the end…there is a way around most things!