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

[Nonya333]

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

i understand but instill need to diagnose the cause of the blown fuse

[dick_barton]

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

Can't be 100% certain but it looks like a 5A slow blow.
https://tinyurl.com/y3pchgd2

[nomoresonys]

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

These powerboards are priced cheap on ebay, that's the way I would go if I wanted to get it going quickly without tracking down the faulty part/s, just need to insure a match by matching the numbers on the white sticker: https://www.ebay.com/sch/i.html?_fro...acat=0&_sop=15

[Nonya333]

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

is it nornal for there be pisitive voltages on backlight negative pins amd if notnwhat causes this?

[Nonya333]

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

i would rather find the fault and increase my diagnostic experience

[Nonya333]

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

also this seems like a main board issue

[alfiedon]

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

Does anyone have the output voltages for CN6101 & CN6102 ?

[DXseekerMO]

Vizio D55-f2 backlight/power supply 20v/24v rail output high 26.5v

So I just got this model Vizio in yesterday with power/sound/image/no backlights. Here's the voltage readings from the Power Supply:

TV plugged in, off state
Pin1-0
Pin2-0
Pin3-0
Pin4-0
Pin5-0
Pin6-0
Pin7-10.06v
Pin8-10.06v
Pin9-10.06v
Pin10-10.06v
Pin11-0
Pin12-0
Pin13-0
Pin14-0
Pin15-0
Pin16-0

TV plugged in, on state

Pin1-26.5v
Pin2-26.5v
Pin3-26.5v
Pin4-0
Pin5-0
Pin6-0
Pin7-12.66v
Pin8-12.64v
Pin9-12.66v
Pin10-12.64v
Pin11-0
Pin12-0
Pin13-0
Pin14-0
Pin15-2.99v
Pin16-3.36v

In addition, upon the Main Board fuse 4501 is open and no voltage is present at the backlight connectors. The source voltage (26.5, 20/24 expected) is present on the voltage in side of the fuse.

The first thing I did was check for a short upon the output side of the fuse from the fuse itself to chassis ground. No short found, meter reads open.

Before I proceed, let me say this. If there were any evidence of even a small short on the output side of the fuse I WOULD HAVE NOT proceeded with the next step!

After finding no short on the output side of the fuse, I used a pair of tweezers to jump the fuse while the TV was in an on state. I expected an arc flash upon contact and did get one, but I think this flash was appropriate for the expected current in this circuit. When the fuse is jumpered the backlights turned on and I saw no evidence of anything in the LED drive circuit overheating. The truth is I didn't expect any since there was no short found on the output side of the fuse.

I'm thinking about ordering a couple fuses and installing one to see if it opens again, but I need to make sure I order the right size and rating of fuse.

As you can see in the picture it is either gray or white with the letter "Y" stamped upon it. Can anyone tell me what the size/rating is for this fuse and whether or not it's a fast or slow-blow type?

If not, can anyone direct me to a resource where I can look it up?

Thanks for your help folks.

[DXseekerMO]

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

All these knowledgeable people in here and no one can tell me how to spec this fuse or direct me to a resource to do it myself?

[nomoresonys]

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

I'll be damed if I know but I did run across this: https://www.google.com/search?client...inboard%2Bfuse

[DXseekerMO]

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

I'll be damed if I know but I did run across this: https://www.google.com/search?client...inboard%2Bfuse

I tried a google search for "SMD fuse identification chart" but didn't find anything. I even called Mouser...they couldn't help either.

[diif]

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

I tried a google search for "SMD fuse identification chart" but didn't find anything. I even called Mouser...they couldn't help either.

I Used "SMD fuse rating" in duckduckgo, it finds a document from Digikey, it's 15A.
Using SMD fuse identification chart in Google, you should have tried images, it shows you what you want.

[R_J]

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

If it is a Matsuo KAH series, (Y) would be 2.5 amp
Bourns SinglFuse™ SF-0603F Series (Y) would be 5 amp
Solidmatrix HA 1206 series (Y) would be 15 amp

[DXseekerMO]

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

If it is a Matsuo KAH series, (Y) would be 2.5 amp
Bourns SinglFuse™ SF-0603F Series (Y) would be 5 amp
Solidmatrix HA 1206 series (Y) would be 15 amp

How does someone tell which one it is? Is the manufacturer name on the fuse somewhere?

[R_J]

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

How does someone tell which one it is? Is the manufacturer name on the fuse somewhere?

Just by looking at the one in the picture it does look like a solidmatrix type

It seems to be on the 24v supply and the power supply can only supply 24v/3.91Amps

[DXseekerMO]

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

Just by looking at the one in the picture it does look like a solidmatrix type

R_J, how are you able to tell they are the manufacturer of this fuse? Is there something about its construction or appearance that gives it away?

Like they say, there's no substitute for experience, and you have way more than me!

[R_J]

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

I looked at the images on google It seems to resemble this type.
If you look at F3201 [T] 5Amp. I would say that is a different maker.

The letter Y is not used on all series of smd fuses
Without the schematic it is just a good guess

[DXseekerMO]

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

I looked at the images on google It seems to resemble this type.
If you look at F3201 [T] 5Amp. I would say that is a different maker.

Yes, I agree F3201 looks different, and I can see why you say that.

If indeed F4501 is 15A that makes me question something else:

That's a high current fuse, and with no short found off the output side of it, what else could make such a high current fuse go open? It seems to me there would have to be a problem in the backlights themselves, or an intermittent short in one/some of the board components? What do you think?

[R_J]

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.

[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.

I can't see it being 15A either, and that's a good idea to solder in that fuse. I believe I will try that. Good call R_J!