My new Duracell flashlight wont stay on when i turn it on it comes on blinding bright thenin about 2-3sec it fades off ,plus comes on very faint all by its self

Duracell KP028 not found on Duracell website.
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DURACELL FLASHLIGHTS

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SOLVED: Need owner's manual - Fixya

The switch needs to be repaired or replaced.

If you can't see a faint picture with the flashlight then the T-con board is gone. If you can see a faint picture, then the led driver or ballasts for the back lights quit. You can get parts from here: TV Parts Universal TV Stands DLP Chips ShopJimmy

Check your brightness settings. It could be that your brightness is turned very high up.

The batteries are probably no good or your charger is bad. But I say the batteries themselves are bad. All batteries will only last so long. And it also depends how often they are keep charged and discharged. Basically all batteries require some kind of maintenance (recharging / discharging).

when the picture goes black, dim the light in the room and shine a bright flashlight on the screen. If you see a faint picture, you have a backlight problem. If this issue came about after you installed the capacitors, double check the installation of your caps. Ensure that you don't have cold solder joints or broken joints!

Dim the lights in the room, turn on the set and shine a bright flashlight on the screen. Do you see a faint picture? If you see a faint picture, you have a backlight fault. Could be several things, you could have a bad backlamp, defective inverter, defective 24vdc power supply, or a faulty main board. I would highly recommend you get a diagnosis

You likely have a LCD set there which may likely use a back light inside to light the image, get the room as dark as you can and with a flashlight illuminate the screen from a angle, with set on if you can see the faint image on the screen of the program you have a Backlight issue'

1. Voltage not there or not being switched on for backlight.

2. Actual back light bad.

If the image can be seen with a flashlight one of the above is the issue and your "picture will appear very faintly" also suggests this.