Samsung HP-T5054 Plasma Y-Sus/Buffer

[kevinm34232]

No video or glow but has audio.

This one upon opening has a blown IC on upper buffer board, and has 4 FETs on Y-SUS with short from drain to source (Q5302, 5303, 5304, 5306 (88N30W)).

Will replacing these and the upper buffer board likely repair this?

I see these buffers are expensive but IC's are cheap, anyone have any luck replacing the IC?

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

I just did one about a month ago. It's a pretty delicate procedure to replace the ICs. Also, on occasion, the ICs can blow violently and fry buffer traces, rendering the board useless. The main problem with these Samsungs is that they don't have fans. I don't touch them anymore, unless I get one for free

One other thing: Be careful where you buy your chips. There are a lot of fakes or recycled chips sold as genuine new.

Edit: Replace all the FETs on that heat sink, and you may have to replace the B20NK50Z FET, also. Sometimes, other components nearby fail.

[kevinm34232]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

I got lucky, the last one of these models I got was just a bloated cap and fuse on the Y-SUS. So I jumped on this one but now I have a project..

How many pins on that IC, I have done 100 pins successfully so far..

BTW on the bottom of the board there are 16 holes under the IC, on the one that is bad there is a ball of solder coming out of one hole.

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

I think there are 32 pins per side, but the pitch is fairly fine. Aligning the chip can be challenging, and it's best done under some sort of magnifier with a pick or nudge tool. I normally use a well tip and drag solder the pins - works great.

Edit: Yes, one of the challenging parts of doing this is removing the IC without tearing the traces. A hot air station is a must. I also use a couple layers of kapton tape to protect the nearby caps and connectors.

[kevinm34232]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

I may give it a go, as I refuse to spend $100 on just that board, and still have to fix the Y-Sus.. Is it common for just those FETs to short?

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

I may give it a go, as I refuse to spend $100 on just that board, and still have to fix the Y-Sus.. Is it common for just those FETs to short?

In a typical failure, just the FETs I mentioned fail. Occasionally, a diode or resistor will fail. I've worked on three of these Samsungs, and one was in really bad shape; the pad under the B20NK50Z mosfet was badly burned. I think the previous owner repeatedly turned the TV on and off in an attempt to test and fix it.

[retiredcaps]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

A hot air station is a must. I also use a couple layers of kapton tape to protect the nearby caps and connectors.

I only have an unregulated hot air gun so I use generous amounts of kapton tape for the surrounding components.

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

I only have an unregulated hot air gun so I use generous amounts of kapton tape for the surrounding components.

And an open window

[kevinm34232]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

You dont have to tell me I got sick from the fumes.. now I open window, put a fan in window, have a small fume extractor fan, wear gloves and a respirator! Sounds extreme but it was not fun..

Ok is there any solder or adhesive under the the body of the IC or just the legs? I have a hot air station but I'm thinking ChipQuik may work OK if not.

Also hypothetically... if this bad IC is -just- removed, and I fix the Y-SUS, should I have a picture at least on the top of the screen?

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

You dont have to tell me I got sick from the fumes.. now I open window, put a fan in window, have a small fume extractor fan, wear gloves and a respirator! Sounds extreme but it was not fun..

Ok is there any solder or adhesive under the the body of the IC or just the legs? I have a hot air station but I'm thinking ChipQuik may work OK if not.

Also hypothetically... if this bad IC is -just- removed, and I fix the Y-SUS, should I have a picture at least on the top of the screen?

There's solder under the center portion of the IC that makes it hard to detach the chip. Patience is EXTREMELY important. I usually concentrate on apply heat to the center of the chip, which also tends to liquefy the solder under the legs. I like to CAREFULLY get under a corner of the chip with a pick tool and gradually allow the chip to work itself free. If you nudge too hard, you will tear traces. I don't like to use ChipQuik.

I wouldn't mess with not having all chips working. These TVs can be pretty temperamental.

[kevinm34232]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

Thanks for the heads up..

The Q5501 you mentioned appears to be OK there is about 1k ohms between 2 lowers pins.

About the question of removing the bad buffer IC, will the TV run without it there?

By the way what temp do you use on for this on the hot air station? I've been using around 340-350C

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

You dont have to tell me I got sick from the fumes.. now I open window, put a fan in window, have a small fume extractor fan, wear gloves and a respirator! Sounds extreme but it was not fun..

Ok is there any solder or adhesive under the the body of the IC or just the legs? I have a hot air station but I'm thinking ChipQuik may work OK if not.

Also hypothetically... if this bad IC is -just- removed, and I fix the Y-SUS, should I have a picture at least on the top of the screen?

There's solder under the center portion of the IC that makes it hard to detach the chip. Patience is EXTREMELY important. I usually concentrate on apply heat to the center of the chip, which also tends to liquefy the solder under the legs. I like to get under a corner of the chip with a pick tool (just slightly under the corner with the tip - not so far under the chip that the pick damages the board) and gradually allow the chip to work itself free. If you nudge too hard, you will tear traces. In general, I don't like to use ChipQuik for any board work.

I wouldn't mess with not having all chips in place. These TVs can be pretty temperamental.

Edit: As you start to feel the chip loosen, continue applying heat and continue to gradually lift the chip until it's fully off the board. Also, remove as much of the silicone RTV as you can before you start this procedure.

Second edit: I wear a P100 respirator when I'm doing this kind of soldering, also.

[kevinm34232]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

Is it necessary to reapply silicone afterwards, is this for the heat?

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

Is it necessary to reapply silicone afterwards, is this for the heat?

I applied silicone. You're going to want to use a silicone that's meant for electronics, as some silicones can cause corrosion. The silicone I bought was MG Chemicals 1035-85ml. Also, I recommend using lots of liquid flux to install the chip.

[retiredcaps]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

And an open window

hmm, that might explain a few things!!

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

hmm, that might explain a few things!!

One whiff of that smoking kapton tape had me scrambling for my respirator.

[kevinm34232]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

Yep I always use plenty of flux, I will let you all know how this turns out, thanks!

[capkid]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

Yep I always use plenty of flux, I will let you all know how this turns out, thanks!

Have fun. Just take your time. I ruined a couple boards on my first couple attempts, but hopefully my lessons learned will be beneficial to you.

[kevinm34232]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

I screwed up here, I was working on Y-Sus and I shoulda moved the damn TV off the table and I noticed afterwards what happened.

Is this panel junk now?? Im afraid to plug in this connector for fear of damaging the new buffer board I have to install.

Will TV work without this one ribbon connected just to test?

[tom66]

Re: Samsung HP-T5054 Plasma Y-Sus/Buffer

It'll work, you'll probably have a horizontal line if you can't fix that.