Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

It's no longer worth it for me to continue on with this. It took 2 weeks to get the mosfets in (had to order in from china) and the buffer chips. I only ordered in 2 of the buffers, so if I replace them--and another blows?

Sometimes you have to know when to call it a day. I'm already into this by about a hundred, and while the intent was to resell at first-it's already at the max that I would invest to repair to resell. And I can't really in good faith sell this as a 'repaired' set knowing how weak that Y board and buffer boards where designed. Serious--why couldn't the designers spend the extra 5 bucks for a flippen' cooling fan?

So I know the power supply board is in good shape, recapped and the regulators. That once sold should recoup the lions share of the expenses. I'm just going to call this a learning project and call it a day.

S-

[freakaftr8]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Your problem was a buffer chip blew our in series and probably threatened another. Sometimes I run an ohm meter down the legs and check for inconsistent readings off the other buffer pins. Can you check voltages without the buffer board in place?

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

side bar note: When I do sell things on eBay like this? I always do full description and let people know what the score is. And I won't sell that Y-Board or the buffer boards due to them being probably still hosed.

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Well. Pretty sad news.

I had to call the family to surround the patient.

Replacement of the blown mosfet went well.

Powered the set up hopeful for a pulse.

And it promptly fried yet another buffer chip in a different location on the board.

I only purchased two of them, one for a spare in case I nackered it during the install.

I'm going to part out the set on eBay. I know the power supply board is in mint shape. (full recap and new voltage regulators) So it's just going to attempt to recoup the expenses I have into it.

Sometimes you just have to know when to call it. It was a great learning time with the plasma sets--but I think I'll stick with the LCD sets. I seem to have a knack with those and the DLP sets.

I wanted to thank everyone for their advice and aid with this one.

S-

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Oddly enough that's why I started messing around with it again. I hate to see stuff hit the landfill for silly reasons. We use craigslist to locate the repairable ones and offer a few bucks to the owners. And I tell 'em upfront that if I can repair the set, I'll likely resell for cost + a percentage for my time. Most are pretty cool with it.

Other posters advertise "Free Recycling of your broken flat panel TV" and they repair them and resell them in pawn shops, or harvest working board parts for other sets or flip the boards on eBay. (that's what they do with broken screen sets)

Yeah it's kinda what I do...except I'll offer a few bucks for it. And be upfront about my intentions. They do it to max out any profit made. Is it legal? Yes. Ethical? Questionable... (I've lost out on about a dozen or so 32" sets...I think these guys must have smart phone ap's that scour Craigslist for sets.... I missed one by 15 minutes..and it was posted 25 minutes prior...)

Ah well. This one is my learning curve. I did already learn my soldering iron may be a high end type by Weller. But it's a pain with mosfets. Heats up the solder at the top of the joint so the solder sucker does it's job. But on that Y-Board the thickness of the board and the copper insert used? The copper soaks up the heat--toasts the board hole slightly, and when you go to remove the mosfet?-- I've had two of the copper inserts come out with it. The electrical connections are still made thankfully. But it taught me a lot about how to remove these buggers.

I'm kinda hopeful that when I upgrade my soldering station I can afford a hot air type rework one, and a 60watt+ adjustable iron. That should help save the board inserts, and make things a lot faster. (For those kids reading this thinking a Radio Shack iron is just "great"? That's my large wattage iron. It sucks. Heats up the part quickly, but the tip drops it's heat to fast when applied to a lug/terminal. By the time you get the solder sucker in your other hand--The iron already gave it up and the solder is hard again..)

S-

[tw2005]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Acetone based with water is the only thing on the bottle. There might be a better method posted on the internet somewhere. It's either made me soft in the head, or the 'glue' soft enough to get a fingernail to lift the stuff off.

They do repair these boards at repair services listed. I'm willing to bet a fiver they won't give up that knowledge easy if asked. So I'm experimenting.

S-

There's nothing like that here, board swappers, market too small, everyone would rather get a new TV compared to the crazy quotes. I do(did) it for fun and did make a few bucks for a while but now, you'd struggle to get good money unless it was a smart tv and not plasma.

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Acetone based with water is the only thing on the bottle. There might be a better method posted on the internet somewhere. It's either made me soft in the head, or the 'glue' soft enough to get a fingernail to lift the stuff off.

They do repair these boards at repair services listed. I'm willing to bet a fiver they won't give up that knowledge easy if asked. So I'm experimenting.

S-

[tw2005]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

I'm a bit lucky in that respect. Wife used to work for a company that made electric meters. She was on the 're-work' bench 8hrs a day for a number of years. She's been kinda nudging me to buy a new solder station and maybe a combo unit with the hot air.

I did see several youtube videos where people used a standard soldering station to replace surface mount chips. Interesting use of solder paste, flux...Seems they skim coat the board itself with solder and then just do a touch/stick/solder method. It's clearly an art form. I think (and this is where I get into trouble) using a combo of tinning the pads using the solder 'paste/flux' and solder--And then careful use of a hot air rework station might make the job faster and smoother.

The IC coming off wasn't that bad. (And I'll probably get slammed for the method) Used nail polish remover to soften the 'glue' that surrounds the chip. I figured the chip was just 'glued' into place, I couldn't quite wrap my noggin around that notion that they would use a hardened silicone glue for the purposes of keeping the tiny pins from arcing over. (Stumbled onto that while researching this). The remains lifted off in tiny soft chunks, but came clean.

From there it was a small exacto style knife and I sliced off the legs at the IC itself. We do that with chips at work on ticket dispensing boards quite a bit. Once all the legs sliced off the chip (did I mention this is not a customer's TV? LOL.) If you hit the legs with a crazy sharp knife it cuts 'em pretty quick without a lot of downward force--that's what you do not want, as it can nick up the board pad/traces.

Once all that was done, just carefully lifted the chip out. Only had minor damage to one pad where 1/2 pealed up. I think there is enough of the remaining pad to get a connection.

As for getting the old legs off the pads--Hot iron and solder wick. I've got a section of solder wick that has about 80 tiny legs sticking to it. Quick and did a decent job--except the one pad.....(learning curve kicked me in the butt)

The only annoying as he(( part? They have a steel insert kinda randomly soldered through the board that looks like it's there to help dispel heat. That steel is still attached. I'm unsure if that is a physical part of the IC itself, or built onto the board. So I'll examine the replacement.

As I've said. The IC is more trial and error. With hopefully less 'errors'. I'd like to do this with a junk PCB first to get my skills up. But I've not any junk boards handy at this time. I've seen first hand the surface mount parts the company I work for has done--And the solution for roaching a pad on such a tiny part. (It's an equally tiny uber thin wire soldered to the pin...and jumpers onto the part the pad connected to before it was damaged.) So I'm kinda inspired, and scared at the same time.

For use of the silicone glue used to keep the thing from arcing over? I'm planning on getting a tube of silicone adhesive sealant. It's very close to what is on it. And I'm fairly sure it's not conductive (but I'll check) Suggestions on that would be welcome.

Thankfully this won't likely be sold to any "customer" That was the intent when I got the power supply board repaired with a recap and new V-Regulators. Right now it's become more of a learning "Quest". I get this way with electronic projects, and also auto repair projects. (2 years electronics training and a 2 year associates degree in automotive tech.) So I do like to tinker with stuff.

I'm rambling again. It's late and I'm going to pass out for the evening.

If anyone is interested, once I get the chip in for the buffer--I'll do set of pictures. Maybe if I screw things up enough others can learn from my mistakes and it can be a help..... (or maybe I'll get lucky and do it right?)

S-

So was that acetone based or acetone free? Daughter loves the nails and has acetone free , i'll give any known working method a go, sounds like it was a good idea.

I think any feedback and photos is always good, someone will always appreciate them. I like seeing peoples work, proves the sometimes too hard is achievable.

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Ya these ic's likely have the grounding pad underneath which makes it hard with just an iron. You might be able to cut the legs carefully (!) then flow fresh solder through the holes beneath the board if it has them and it may just come right off.

I was close!! That pad is the part left under the chip on mine. (The chip was toasted and crusty, so that part is still hanging on the board)

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

well if you get this done and successfully do those buffer ICs, feel free to throw some tips back because that's one main reason I have not bothered , that and the amount of damage i have on the ymain and PSU.

I'm not super confident getting the ic off, then on again and I have no hot air

I'm a bit lucky in that respect. Wife used to work for a company that made electric meters. She was on the 're-work' bench 8hrs a day for a number of years. She's been kinda nudging me to buy a new solder station and maybe a combo unit with the hot air.

I did see several youtube videos where people used a standard soldering station to replace surface mount chips. Interesting use of solder paste, flux...Seems they skim coat the board itself with solder and then just do a touch/stick/solder method. It's clearly an art form. I think (and this is where I get into trouble) using a combo of tinning the pads using the solder 'paste/flux' and solder--And then careful use of a hot air rework station might make the job faster and smoother.

The IC coming off wasn't that bad. (And I'll probably get slammed for the method) Used nail polish remover to soften the 'glue' that surrounds the chip. I figured the chip was just 'glued' into place, I couldn't quite wrap my noggin around that notion that they would use a hardened silicone glue for the purposes of keeping the tiny pins from arcing over. (Stumbled onto that while researching this). The remains lifted off in tiny soft chunks, but came clean.

From there it was a small exacto style knife and I sliced off the legs at the IC itself. We do that with chips at work on ticket dispensing boards quite a bit. Once all the legs sliced off the chip (did I mention this is not a customer's TV? LOL.) If you hit the legs with a crazy sharp knife it cuts 'em pretty quick without a lot of downward force--that's what you do not want, as it can nick up the board pad/traces.

Once all that was done, just carefully lifted the chip out. Only had minor damage to one pad where 1/2 pealed up. I think there is enough of the remaining pad to get a connection.

As for getting the old legs off the pads--Hot iron and solder wick. I've got a section of solder wick that has about 80 tiny legs sticking to it. Quick and did a decent job--except the one pad.....(learning curve kicked me in the butt)

The only annoying as he(( part? They have a steel insert kinda randomly soldered through the board that looks like it's there to help dispel heat. That steel is still attached. I'm unsure if that is a physical part of the IC itself, or built onto the board. So I'll examine the replacement.

As I've said. The IC is more trial and error. With hopefully less 'errors'. I'd like to do this with a junk PCB first to get my skills up. But I've not any junk boards handy at this time. I've seen first hand the surface mount parts the company I work for has done--And the solution for roaching a pad on such a tiny part. (It's an equally tiny uber thin wire soldered to the pin...and jumpers onto the part the pad connected to before it was damaged.) So I'm kinda inspired, and scared at the same time.

For use of the silicone glue used to keep the thing from arcing over? I'm planning on getting a tube of silicone adhesive sealant. It's very close to what is on it. And I'm fairly sure it's not conductive (but I'll check) Suggestions on that would be welcome.

Thankfully this won't likely be sold to any "customer" That was the intent when I got the power supply board repaired with a recap and new V-Regulators. Right now it's become more of a learning "Quest". I get this way with electronic projects, and also auto repair projects. (2 years electronics training and a 2 year associates degree in automotive tech.) So I do like to tinker with stuff.

I'm rambling again. It's late and I'm going to pass out for the evening.

If anyone is interested, once I get the chip in for the buffer--I'll do set of pictures. Maybe if I screw things up enough others can learn from my mistakes and it can be a help..... (or maybe I'll get lucky and do it right?)

S-

[tw2005]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Ya these ic's likely have the grounding pad underneath which makes it hard with just an iron. You might be able to cut the legs carefully (!) then flow fresh solder through the holes beneath the board if it has them and it may just come right off.

I was thinking along those lines but I tried that with a panasonic buffer with no soldered pad but the silicone they use is flowed under the chip glued it fast. then I had an issue getting all the slicone off the pins and when i tried desoldering the heat and the slicone just tore most of the pads.

So the area I'm thinking I need some ideas are, how to get the silicone off clean, then with a very sharp knife cut the legs ip hard against the caisng then desolder the pins.

I think I can pull off hand soldering with a good lense and plenty of flux.

Wish i kept some of my dead uppers from previous samsungs as backup or practice, bt seriously I never wanted to touch another of these just that one at work retired and it was being dumped.

[mmartell]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Ya these ic's likely have the grounding pad underneath which makes it hard with just an iron. You might be able to cut the legs carefully (!) then flow fresh solder through the holes beneath the board if it has them and it may just come right off.

[tw2005]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Sorry about vanishing and not responding quicker. TWC went "Poof" in my area for about 3-4 hours.

I'll update once I replace what I know is shorted out and those two capacitors that are domed pretty bad. (That can't be helping matters any)

Might take a few days to get parts in, so I'll park this on the back burner until I get the parts in.

My thanks for everyones help with it. It's a far cry from the LCD ones and the DLP sets I've had excellent luck with.

S-

well if you get this done and successfully do those buffer ICs, feel free to throw some tips back because that's one main reason I have not bothered , that and the amount of damage i have on the ymain and PSU.

I'm not super confident getting the ic off, then on again and I have no hot air

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Sorry about vanishing and not responding quicker. TWC went "Poof" in my area for about 3-4 hours.

I'll update once I replace what I know is shorted out and those two capacitors that are domed pretty bad. (That can't be helping matters any)

Might take a few days to get parts in, so I'll park this on the back burner until I get the parts in.

My thanks for everyones help with it. It's a far cry from the LCD ones and the DLP sets I've had excellent luck with.

S-

[mmartell]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

You should be fine running the YMain without the buffer board. Plug in the power and the ribbon from the control board and fire it up and watch for the green led when it begins to buzz. I would wait until you replace your bad parts first.

Also agree with tw that these have mostly simple well documented shorted fets and occasionally a shorted diode nearby.

Replacing the ic on the buffer board can be done - carefully.

[tw2005]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

I'll double check. Currently I'm not quite 100% after all that pulling, drilling, and tugging. (Feel like I went 3 rounds with Frazer)

I get the feeling the basic repair kit should be ordered in, questionable parts replaced (heck, the ones that tested bad)

In order not to pop anymore buffer chips--Can things be fired up to check for that fault LED with the edge connectors to the panel being left unplugged--or would that do more harm then good.

Honestly I'm at the point where I'm going to probably pull the mosfets behind that row of red caps just to be sure. The testing in circuit is suspect at best and inconclusive.

S-

I honestly not sure what happens with the ymain fired up with no buffer whether it will start up or go protect> i would only hook up the buffer once you have all bad ics removed and confirmed no short as it may damage the ymain.

I would expect if the ymain was repaired and assuming it starts up or has no detection for the buffers removed then no protect would trigger, at the moment you have a dead short on the output with the bad 88N30W.

In the panasonics they do have a cct to detect any buffer disconnected and will shutdown, samsung and Panasonic are chalk and cheese really for me. At least their manuals have full diagrams and you can get down and see the protection ccts. samsung, very limited info, more for board swapping, not the deeper level stuff which is why I'm biased towards panasonic and overall quality is better

[tw2005]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Minor update of sorts. Tested a couple of the mosfet's on the side with all the red capacitors. Thankfully the circuit seems to mirror. So I pulled and tested two from one row. Good. I then compared what those two 'good' ones did in circuit, against the two ones I didn't really want to pull.


Okay... That brings me to: B20NK 50Z GK138 VW CHN 704

This is the one that was pointed out in picture 5 (Thanks for pointing it out!)


Okay. Had to pull the surface mounted legs to test it.

It's doing the same thing the K2837 was doing.

Black lead on the source
Red lead on the drain.

Tested in diode test with "OL" This is expected.

Bump the Red lead over to the gate.

Return back to the red lead to the drain. Triggers the meter with about 1ohm resistance---good right? Maybe......not..... Leave the meter lead on the drain and I can watch the reading climb rather quickly like a capacitor chargeing...and then the meter will "OL" within a few seconds.

The trick with touching the gate/leads with the finger will shut the drain off and it will be "OL" until I touch the red lead back to the gate...at that time it starts off at about less then 1...then start to raise up until "OL".

Now I know it's nothing to do with the board, I had both leads (source and gate) off the board using jumpers.

Now I'm getting really confused. The other mosfet's I tested, except the shorted one and the K2837... All turned 'on' and stayed 'on', until I touched the leads.

Is this how it is supposed to work, or do I need to replace this part?

Thanks for pointing it out!!!

S-

My thoughts are if it's not shorted out, it's ok. You may be going a little deep into this. I can only give you my experience and that is they fail short. I have more experience with the Panasonic boards and the IGBTs go short but I have had a couple show 100-200ohms between legs out of cct and they were bad.

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

Minor update of sorts. Tested a couple of the mosfet's on the side with all the red capacitors. Thankfully the circuit seems to mirror. So I pulled and tested two from one row. Good. I then compared what those two 'good' ones did in circuit, against the two ones I didn't really want to pull.


Okay... That brings me to: B20NK 50Z GK138 VW CHN 704

This is the one that was pointed out in picture 5 (Thanks for pointing it out!)


Okay. Had to pull the surface mounted legs to test it.

It's doing the same thing the K2837 was doing.

Black lead on the source
Red lead on the drain.

Tested in diode test with "OL" This is expected.

Bump the Red lead over to the gate.

Return back to the red lead to the drain. Triggers the meter with about 1ohm resistance---good right? Maybe......not..... Leave the meter lead on the drain and I can watch the reading climb rather quickly like a capacitor chargeing...and then the meter will "OL" within a few seconds.

The trick with touching the gate/leads with the finger will shut the drain off and it will be "OL" until I touch the red lead back to the gate...at that time it starts off at about less then 1...then start to raise up until "OL".

Now I know it's nothing to do with the board, I had both leads (source and gate) off the board using jumpers.

Now I'm getting really confused. The other mosfet's I tested, except the shorted one and the K2837... All turned 'on' and stayed 'on', until I touched the leads.

Is this how it is supposed to work, or do I need to replace this part?

Thanks for pointing it out!!!

S-

[Tedybear]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

The SMD FET i was referring to, is in pic 5. I was hoping since there are'nt many on that board and the part number I gave,you may have found it.

I've only had a fairly simple approach to these. Inspect looking for burns, I think sometimes the resistors near the outputs burn, bell out all the fuses there's also some small green pico apart from the obvious , check diodes and fets for shorts, remove what's shorted, confirm out of cct.

I know if 1 88N30W shorted, shorts the rest in cct but I have had one board with only 1 bad and that was the only part needed. So with the bad 88N30w removed , I assume no more shorts exist in that bank of them, and sounds like the 2SK2837 is not shorted.

I'll double check. Currently I'm not quite 100% after all that pulling, drilling, and tugging. (Feel like I went 3 rounds with Frazer)

I get the feeling the basic repair kit should be ordered in, questionable parts replaced (heck, the ones that tested bad)

In order not to pop anymore buffer chips--Can things be fired up to check for that fault LED with the edge connectors to the panel being left unplugged--or would that do more harm then good.

Honestly I'm at the point where I'm going to probably pull the mosfets behind that row of red caps just to be sure. The testing in circuit is suspect at best and inconclusive.

S-

[tw2005]

Re: Phillips 50pfp5332d/37--BlownUP Buffer Chip!! NO PICTURE ON SCREEN!

I think the server gods must be taking pity on me. (just got back from having a wisdom tooth pulled out by an oral surgeon....took over an hour doing it..and over an hour waiting for my cardiologist to give clearance for the procedure.)

Sense the server seems to want me to upload photos.... The ones behind the red caps. Those I'm wondering about checking in circuit, because they are in a PITA location.

The ones across from the edge connectors have been checked. And the missing ones are the ones that failed testing.

Can anyone, using the photos provided (and I can probably get more if needed) let me know of any other support parts/circuits that need to be checked? Such as mosfets normally have a small driver transistor that tells 'em when to turn on and off. Any such beastie on this, and can anyone let me know where and how to test?

I have to hold off for a few days before ordering in more parts. The two capacitors with a severe case of "Chrome Dome" will be replaced tomorrow when they show up. The rest of the parts? I might have to bite the bullet as a few of the numbers are kinda elusive to find with the company I've been using locally.

Feel free to "Ring my phone" so to speak. I'm here curled up waiting for the lideocane to wear off (or however ya spell it)

S-

The SMD FET i was referring to, is in pic 5. I was hoping since there are'nt many on that board and the part number I gave,you may have found it.

I've only had a fairly simple approach to these. Inspect looking for burns, I think sometimes the resistors near the outputs burn, bell out all the fuses there's also some small green pico apart from the obvious , check diodes and fets for shorts, remove what's shorted, confirm out of cct.

I know if 1 88N30W shorted, shorts the rest in cct but I have had one board with only 1 bad and that was the only part needed. So with the bad 88N30w removed , I assume no more shorts exist in that bank of them, and sounds like the 2SK2837 is not shorted.