fpt5084 already been repaired once by a "pro"

[cashkennedy]

I got this set today(Samsung fpt5084 50" plasma) and knew that it would be funny when they seller handed me a handful of bad caps that the electronics person he had taken it to a few years ago had given him after the repair. He also accidentally showed me the bill for the repair, $1200 for replacing about 10 caps. I was like "wow you got taken for a ride" and he said it was a friend of the family...

So I got home and took the back off and this is what I saw:

[cashkennedy]

Re: fpt5084 already been repaired once by a "pro"

Picture 2 : That's 2 fuses in a stack with the holster completely melted around 1 side and the wire he stuck in there loose on 1 side

Picture 4 : Caps are ganged up in parallel (maybe he was trying to get 1500 uF from a 1000uF and a 470uF, though the larger panny is a gp cap I think? series M I think? and the nichicon is VZ (not sure on what that series is, might be low esr) plus he didn't do all the caps ... and furthermore im pretty sure the 2 ganged together were replacing a 2200 uF cap, so I don't think he even replaced it with as much capacitance...

Picture 3 are some of the remaining samwha caps that ill replace cause theyre popped.

Not sure if the fuse came loose and stoped the set from working, or if the obviously popped cap caused the fuse to overheat?

[johnboy1313]

Re: fpt5084 already been repaired once by a "pro"

$1200???? What??!?!??!!

[martyparish]

Re: fpt5084 already been repaired once by a "pro"

Shoot, that was the "Family Price" !

[tom66]

Re: fpt5084 already been repaired once by a "pro"

Holy hell how can anyone charge $1,200 for that work is beyond me.

[cashkennedy]

Re: fpt5084 already been repaired once by a "pro"

So im gonna try to fix it cheaply by just replacing the fuse holder with something more robust, and replace the remaining samwha caps in the 10-30v range.

And ideas what would cause the fuse holder to melt, beyond the fact that theres some loose wires soldered to it... and how his wire on 1 side of the fuses came unsoldered seems odd, these are hot sets, but shouldnt be that hot? Could the bad caps on the secondary put so much load on the set that the fuse holder melted, but the fuse didnt pop:?

[tom66]

Re: fpt5084 already been repaired once by a "pro"

It looks almost like he may have shorted the fuse with solder, so the answer may well be due to an overload which used the holder as a fuse rather than the fuse itself...
Or perhaps he just melted it with his soldering iron.

[budm]

Re: fpt5084 already been repaired once by a "pro"

I think he may have bypassed the blown 12A fuse by soldering in a piece of wire between the two fuse clips.

[cashkennedy]

Re: fpt5084 already been repaired once by a "pro"

So I desoldered the fuse holder and put in 3 inches of 16 guage wire, braided copper, had to trim a tiny bit from each end to get it to fit in the hole. Hopefully roughly 18 guage is good enough for 12amps.

Also replaced the last 4 low volt filter caps on the secondary, left the other guys ganged caps in place cause idk what uF they were to start with. Is that a retared trick that some electricians do when they don't have the cap they need? should I assume he used 1000 + 470 for 1500?

TV works now.

Ive never owned a plasma and this is the first ive ever taken apart. It scares me though, I keep a fire extinguisher next to it cause of how loud it clicks when turning on and off.

It also hums a tiny bit like a floruescent ballast. Can only hear it if you have the volume down to 0 . Is it normal for plasmas to hum a bit?

[cashkennedy]

Re: fpt5084 already been repaired once by a "pro"

I was worried that 18 gauge wouldn't be enough , because when you run romex in a house you need 14 gauge for 15 amp circuits, but its looks like wire sizing is related to the length of the wire as well / and thus since I only used 3 inches I am probably in the clear / not enough ohms while traveling to heat it up much? then again there's less metal to sink it since its a short jumper...

[capkid]

Re: fpt5084 already been repaired once by a "pro"

So I desoldered the fuse holder and put in 3 inches of 16 guage wire, braided copper, had to trim a tiny bit from each end to get it to fit in the hole. Hopefully roughly 18 guage is good enough for 12amps.

Also replaced the last 4 low volt filter caps on the secondary, left the other guys ganged caps in place cause idk what uF they were to start with. Is that a retared trick that some electricians do when they don't have the cap they need? should I assume he used 1000 + 470 for 1500?

TV works now.

Ive never owned a plasma and this is the first ive ever taken apart. It scares me though, I keep a fire extinguisher next to it cause of how loud it clicks when turning on and off.

It also hums a tiny bit like a floruescent ballast. Can only hear it if you have the volume down to 0 . Is it normal for plasmas to hum a bit?

Yes, the caps were most likely soldered in parallel to make up the 1500uF. The first plasma I bought was a 50" Panasonic (still own it), and I felt nervous working on it because of the amount of current flowing through it. Plasmas do make a bit of a buzzing sound when they run, but I'd take a plasma over an LCD any day.

[Th3_uN1Qu3]

Re: fpt5084 already been repaired once by a "pro"

I keep a fire extinguisher next to it cause of how loud it clicks when turning on and off.

It's got a relay in it. That's what clicks.

I was worried that 18 gauge wouldn't be enough , because when you run romex in a house you need 14 gauge for 15 amp circuits, but its looks like wire sizing is related to the length of the wire as well / and thus since I only used 3 inches I am probably in the clear / not enough ohms while traveling to heat it up much? then again there's less metal to sink it since its a short jumper...

Yes, wire size is related to the length, because wire has resistivity (measured in ohms*meter). Depending on the thickness and length, this translates to the more familiar resistance. Here. Scroll down a bit for a calculator.

The wire you put in is way too THICK to be a fuse. It will never blow in case of an overload - something else will instead. Best would be to put a proper 15A fuse in there.

[tom66]

Re: fpt5084 already been repaired once by a "pro"

Am I the only one who likes the gentle buzzing sound a plasma produces? You can't hear it from 6/10ft so it doesn't interfere with viewing but it's fun to listen to it change with picture brightness and such.

[cashkennedy]

Re: fpt5084 already been repaired once by a "pro"

Ill see if I can find a 12amp fuse somewhere convenient, I don't really want to order 1 fuse from mouser. Radio shack probably has glass fuses like that, but I don't know how well woldering to the side of a fuse works long term considering that's what the last guy did and only lasted 1-2 years. He was using a 5 amp and a 10 amp to get over the 12amp fuse requirement.

Ill replace his ganged up caps too once I have it out again, only 3 more caps basically.

The humming it makes is very soft / non parasitic, so its not annoying, but Ill inform your gf to mute 2 plasmas and put them on both sides of your bed when yall are making love.

[tom66]

Re: fpt5084 already been repaired once by a "pro"

Well, you must have a noisy plasma, my Panasonics don't produce any audible sound at 6~10ft, you can hear it up close (like ear to the vent) but otherwise you can't hear it.

[capkid]

Re: fpt5084 already been repaired once by a "pro"

Yeah, my Panasonic isn't that noisy at all, but plasmas in general make a buzzing sound. I was assuming he doesn't have a Panasonic. The only thing I hear from the Panasonic is the fans moving, but they're not loud enough to affect the TV-watching experience.

[tom66]

Re: fpt5084 already been repaired once by a "pro"

Given the heat that older plasmas produce, fans are essential in my opinion. Mine are super quiet, I can't hear them at all.

[cashkennedy]

Re: fpt5084 already been repaired once by a "pro"

My ears are really good, i can hear it about 3-6 feet from it, but no further. So its probably fine / no worse then your average set.

This samsung set has a fancy card on the power supply thats suposed to sense fan / voltage failures and turn off the set, but I dont see any fans / or hear any fans...

[tom66]

Re: fpt5084 already been repaired once by a "pro"

Just a PSU sequencing micom. Necessary to switch on everything in order, simpler than using lots of discrete timing circuits. Most Samsung and LG plasmas I have seen do not have fans.