Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

[diif]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

The three makers R_J references all have different size fuses, you should be able to determine the maker with a micrometer.

[DXseekerMO]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

I would install something like a 3~5 amp pigtail fuse in that position and see what happens. The short may not be on the fuse but the circuit that runs off that supply may be loading it down.
Like I said, based on the power supply rating I can't see it being a 15 amp fuse.

The three makers R_J references all have different size fuses, you should be able to determine the maker with a micrometer.

So after returning from physical therapy this evening I cracked open the TV, piggyback soldered a low current automotive AGC type fuse holder to each end of the fuse and installed a 3A AGC type fuse, all from my auto parts collection. I have plenty of car stuff since before repairing TVs I was a Master Auto Technician and an I-Car certified collision repair/body and paint technician. Currently the TV now has backlights and is in operation in my kitchen. It's been on for 20 minutes.

There's just one question before I temporarily put the back on it for testing. Since cars are a 12 volt system and this circuit is 24 volt, should I have installed a different rating fuse? I'm thinking it should be ok but I wanted to ask, just in case.

[DXseekerMO]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

8 hours run time and the backlights are still on.

I'm still looking to find out if the current rating on the automotive fuse is 3A at 24V. Anyone? And I meant ATC type fuse in my previous post, not AGC type.

[R_J]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

The voltage rating is not that important in this case. The voltage rating has more to do with the distance between the contacts. an atc fuse would not be good in a 120v circuit, If the fuse opened it might continue to arc across the open fuse element.
I would just replace it with a 3~5 amp smd fuse that will mount to the pads.

[DXseekerMO]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

The voltage rating is not that important in this case. The voltage rating has more to do with the distance between the contacts. an atc fuse would not be good in a 120v circuit, If the fuse opened it might continue to arc across the open fuse element.
I would just replace it with a 3~5 amp smd fuse that will mount to the pads.

Ok so I found a fuse from a t-con board with the markings "YD". The rating printed on the board was 32V 5A. I removed it from the t-con, installed it on my main board, checked it for continuity after the install and it checked good. I installed the main board, plugged it in, turned the TV on and the fuse blew straightaway. Looks like the Main Board has a problem. Now for where to start?

[cheeky2]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

I bet the fuse should have been a slow blow fuse and your fuse you put in it was a fast blow fuse. Which is why it blew straight away!

[DXseekerMO]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

I bet the fuse should have been a slow blow fuse and your fuse you put in it was a fast blow fuse. Which is why it blew straight away!

You may be right. I need to see if I can find the right fuse for it.

[R_J]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

Maybe it is indeed a 15amp just to handle the surge. Does it still work with the atc fuse?

[DXseekerMO]

Re: Vizio D55-f2 backlight/power supply 20v/24v rail output high 26v

Maybe it is indeed a 15amp just to handle the surge. Does it still work with the atc fuse?

Yes it does work with the ATC fuse, it's a 3A rated fuse