Audiovox Plasma TV Fuse Blown


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Audiovox Plasma TV Fuse Blown

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vorp
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Jul 13, 2009, 11:42 PM

Post #1 of 26 (11497 views)
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Audiovox Plasma TV Fuse Blown	Can't Post

I have a Audiovox fpe3207. It stopped working and I opened it up. A has blown a fuse but I can't tell what size to replace it with. Any ideas? It says fu503 next to it on the board and whats left of the covering of the fuse is a brownish color.

jts1957
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Jul 13, 2009, 11:46 PM

Post #2 of 26 (11492 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Pix?
Covering & board area near fuse.

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Location: Far, Far Away

(This post was edited by jts1957 on Jul 13, 2009, 11:47 PM)

vorp
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Jul 14, 2009, 2:02 AM

Post #3 of 26 (11487 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Here are the pics.

I can't get my camera to get a very good pic the numbers on the board. I hope this helps if not let me know.

Thanks!

BP

jts1957
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Jul 14, 2009, 6:37 AM

Post #4 of 26 (11484 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Found - similar model:
Audiovox : Fpe3706 : Dead Ticks, replace fu503 and 2200 35v in 24 supply in ps.

Unfortunately, they didn't note the fuse value.
I was hoping that pictures would show fuse/fuse value ID sticker. Screwdriver pointing to fu503 physical location.

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Location: Far, Far Away

vorp
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Jul 14, 2009, 12:42 PM

Post #5 of 26 (11480 views)
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Re: [jts1957] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

So I am out of luck.

Thanks for the help. All of the identifying info from the fuse has was melted off. The only other fuse on the board is a different color.

If suggest anything else let me know, but I do appreciate your help

BP

jts1957
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Jul 14, 2009, 8:17 PM

Post #6 of 26 (11475 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Two things:

Have you tried email Audiovox? Doubtful, but worth a shot.

Could try the " Crazy

" method. Start with a .5 Amp fuse and if it blows raise value by .5 or 1 Amp until the fuse stops blowing and set either works or sends out smoke signals. Wink

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Location: Far, Far Away

tscheucher
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Jul 15, 2009, 7:15 AM

Post #7 of 26 (11466 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Hi vorp!
Audiovox is a non common brand in Europe and only to purchase via online distributers. You posted some very conclusive images of the power pcb which let me think of a product from DELTA Electronics from the far east. At first sight I assume that the fuse is linked to a schottky diode (mounted at the black heatsink at the side) at the supply�s secondary output (somewhere between 12 and 24V) which is saving it from short circuit deaths due to overloads.
The first thing in such cases is to figure out if something is shorted at the main pcb�s power input (the board the graphic/upscaler, memory and software ic�s are located) or the voltage inverter board. It�s mostly triggered by bad electrolytic capacitors or shorted mosfet�s on the inverter caused by bad inverter transformers.
The fuse fu503 itsself is a special construction due to save production costs and to allow the power supply�s operating IC (SMPS - IC) taking measures of current consumption as a feedback for checking the device�s health status. They just took a fusible resistor for that job. It�s value isn�t that important as long as it doesn�t exceed 10 Ohm. In your case, and obviously without a service manual, I would recommend you to take a 3,3Ohm carbon film resistor with 0,25Watt as a replacement. It�s value is low enough for passing a high current and to blow again in cause of persisting short circuiting.
If it blows off again, immediately unplug your set from the mains and take measures for short circuits, as I mentioned before, on the main pcb and the surrounding area of the blown fuse on the power supply�s pcb. Make sure that there are now bad solder joints or leakages within switching rectifiers (diodes) and replace the 3 electrolytic capacitors close to the fuse just precautionary. According the photo you made, their value must be somewhere around 680 - 2200uF and 25 -35V.
I will try to get a schematic and will announce again, if I didn�t get positive feedback from you (If your tv is still on strike...).
Good luck!
TS

vorp
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Jul 15, 2009, 11:06 PM

Post #8 of 26 (11454 views)
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Re: [tscheucher] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Wow, Thanks for the info. I must say though most of it is was over my head. But you suggest that I replace that fuse with a 3,3 ohm carbon film resistor with 0,25 watt. Even though it is was a fuse? I can try that. But i bet there may be other problems with the set. I was hoping it just blew due to a power surge or something.

Thanks this is very helpful.

BP

tscheucher
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Jul 17, 2009, 10:38 AM

Post #9 of 26 (11446 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Yep - You can use a carbon film resistor as well. A fuse, as you know, is nothing but a special piece of wire with other properties.
The material they took therefore makes the fuse�s wire melting away in case of over temperature or too high currents.

I know, I don�t need to tell you that - I just wanted to explain why there a resistor can be used.

One thing is sure - There was no power surge from the mains because in that case components of the primary supply circuit must have been gone on damage but your fuse is located in the secondary part of the supply and the scorch marks on your pcb indicate over current and heat death of the fusible resistor.

A 3,3 Ohm resistor is no barrier for passing currents above 0,5mA - In your case I suppose currents are between 1,2 and 4 A because of the size (value) of the electrolytic capacitors they used.

SMPS (switching mode power supplies) are electronically regulated supplies, for which it is necessary to have a current measuring unit included. This task is up to the SMPS - controller with feedback mostly from the secondary side of the supply (behind the transformer = low voltage area).

I looked at your picturs again and I�m very sure that the failure can be found within the 15V circuit (the plug with the 3 red wires).

Their voltage is too high for supporting the digiboard so I assume that the failure must be somewhere around X/Y - corrector boards or inverter for lighting up the plasma panel.

Did the fuse blow again?

TS

(This post was edited by tscheucher on Jul 17, 2009, 10:41 AM)

rrobor
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Jul 19, 2009, 1:17 AM

Post #10 of 26 (11429 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

With the scorch mark as that resistor fried, 3.3ohms is too high, its going to be less. The resistor also has to be a safety resistor not a standard type. The scorch tells you there is a short so you need to find that first.

vorp
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Jul 19, 2009, 2:35 PM

Post #11 of 26 (11421 views)
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If there is a short I will have a hard time finding it.

Thanks,

BP

jts1957
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Jul 19, 2009, 7:37 PM

Post #12 of 26 (11419 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

No Meter?

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Location: Far, Far Away

factoredreality
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Sep 15, 2009, 12:36 AM

Post #13 of 26 (11227 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Did you ever determine the cause of the blown FU503? I recently rescued an Audiovox FPE 3206 from the dumpster with the same problem. TV powers on but no backlight.

FU503 is cooked but FU502 is intact. I bugged the power board and didn't find any shorts so I'm going to check down the line a bit.

I'll update if I discover anything.

Nate

mikemaiertv
Enthusiast

Sep 15, 2009, 11:28 PM

Post #14 of 26 (11218 views)
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Re: [factoredreality] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

FU503 is or was a 6 amp fuse
Mike Owens Owner Competition TV Spokane WA.

factoredreality
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Sep 16, 2009, 3:15 AM

Post #15 of 26 (11211 views)
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Re: [mikemaiertv] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Great thanks for the value of the fuse.

My iron was at work, I had put a 2.2 ohm 1/4W resistor in there. Little late tonight but I should get the power board back in and check the voltages tomorrow.

Thanks
Nate

rrobor
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Sep 16, 2009, 10:41 AM

Post #16 of 26 (11204 views)
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Re: [factoredreality] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Watts = amps X volts Volts is 24V A well its a 6A fuse, to blow that and burn the fuse took that so thats 144 Watts. Your resistor will be an interesting thing for the odd millisecond.

factoredreality
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Sep 16, 2009, 1:46 PM

Post #17 of 26 (11202 views)
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Re: [rrobor] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Agreed, however to check the voltage coming off the power board without a load attached the resistor should be more than efficient.

Now if I were to connect the power board to the rest of the TV, and the TV actually pulls the rated value of the 6A fuse, then yes Ohm's law is gonna nuke that poor little resistor.

I'm only hoping to validate the power supply before I place my mouser order in case something upstream is not functioning correctly either.

kev2971
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Sep 21, 2009, 10:23 AM

Post #18 of 26 (11176 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

looks like capacitor leaked out on to board have you checked the capacitors?

vorp
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Sep 22, 2009, 10:30 PM

Post #19 of 26 (11157 views)
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Re: [kev2971] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

I have not tried to fix the board. I will though now that I know the value of the fuse.

I have checked the caps. I think they are all fine, none seem to bulge.

Thanks for all

Vorp

76hearse
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Feb 8, 2010, 2:52 AM

Post #20 of 26 (10746 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

I just ran across one of the tv's also. Blue power light, no sound, no picture. I replaced the inversion board, still no picture. traced the power cable back to the power supply, and sure enough, no voltage. I have the same fuse blown. FU503, removed it from the board, its a 7A fuse.

vorp
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Feb 8, 2010, 2:54 PM

Post #21 of 26 (10742 views)
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Re: [76hearse] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

I also replaced the Fuse with a 7A. TV works fine. Although the picture is terrible.

Thanks for everything

76hearse
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Feb 8, 2010, 5:23 PM

Post #22 of 26 (10741 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

At lease you have a picture, I now have voltage going into the tuner board but no voltage going to the inverter board still. going to replace the tuner board next, and cross my fingers

thunderodb
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Jan 22, 2011, 3:02 PM

Post #23 of 26 (9714 views)
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Re: [vorp] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Digging up a somewhat old thread here, but I was given a FPE3706 by the owner of the local Radio Shack and told it didn't work. That turned out to not be entirely true.
I brought it home and tried turning it on and the screen lit partially and blinked in and out, so I proceeded with disassembly. I also found this thread. I looked at FU503 and it was popped, but I could still read it. It WAS a Buss 5A 125v fuse. I went back to Radio Shack and bought an in-line fuse holder and a package of 5A 125v glass fuses.
I replaced the burnt fuse with the fuse holder and a glass fuse, the tv turned on and had a great picture. I will admit I got a little excited. I hooked the TV up to the cable and let it start searching for channels. I left the TV alone for about 10-12 minutes and when I came back it was off. I tried turning it off and back on to no avail.
I disassembled it again this weekend and, sure enough, it had blown the fuse again, so I changed the fuse and used my meter to test the DC output of the supply. It puts out 24.1v at all of the 24v connections and 17.23 at the 18v connections. I would think this should be sufficient.
FU503 is in the 24v circuit that feeds power to the inverter board. I will be ordering one of these shortly I will post in this thread if that fixes the problem.

I wouldnt mind if a $60 investment fixes this tv. If it doesn't fix it, oh well. I have an RCA D52W20 52" Rear-projection TV that we bought for $50 and fixed for $125. It worked well for 1� years and recently popped a capacitor, which is why I was at Radio Shack in the first place, lol. I replaced that cap for $1.50 and the TV is back to working perfectly.

jts1957
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Jan 22, 2011, 8:24 PM

Post #24 of 26 (9706 views)
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Re: [thunderodb] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Any electrolytics on the inverter board?

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Location: Far, Far Away

thunderodb
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Jan 29, 2011, 2:10 PM

Post #25 of 26 (9667 views)
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Re: [jts1957] Audiovox Plasma TV Fuse Blown [In reply to]	Can't Post

Do you mean have any caps on the inverter board that leaked? Not that I can see, why?

If your question is are there any electrolytic caps on the board, yes, there are.

(This post was edited by thunderodb on Jan 30, 2011, 8:20 PM)

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