Hitachi TV LED Problem

[Callumb]

I have a hitachi 42 inch led tv. The model number is "42HXT12U". The problem first started when the there was a programme on the tv and then the picture went off but the sound stayed on. When a bright flashlight is shined on the screen the image can be seen. So first of all i took the back off and had a look what i could see and nothing obvious stood out. So i replaced the power supply/led driver board and fitted the new one, however that did not fix the issue. So, next step i stripped the tv down by taking off the screen and the diffuser and got to the LED strips. From the power supply board the LEDS are being supplied with 11.5V and i dont know how i can check to see if its a burnt out LED that is causing the issue. If anyone has any suggestions i would be very grateful.
Many thanks

 

[Hamperking68]

The chances are it's a issue with the LED's themselves. The bad part is that you have now voided any warranty on the TV.

 

[Callumb]

The chances are it's a issue with the LED's themselves. The bad part is that you have now voided any warranty on the TV.

It was already out of warranty

 

[budwich]

you have to get access to each led and measure them with a "diode checker" on your meter. Likely issue is the first or last led in the "string" is bad. Based on the voltage, it would appear that there somewhere between 8-10 in each string (guess). Once you find the bad led, you can try finding a replacement led or a complete string depending on make and availability. Go to badcaps.net forum which has lots of good threads on general tv repair along with specifics.

 

[mgallacher68]

Use multimeter in diode mode test each one or 12 v supply and touch + & - on strips to see the bab bulb