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

[Tedybear]

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

Currently anymore testing will have to wait. I've tested out of circuit most of the MOSFETS so far and already found 2 that where shot. I did find two repair kits via eBay. (I love shopjimmy as well, but I didn't see anything this time around for this, other then out of stock of the board and the mosfets)

http://www.ebay.com/itm/SAMSUNG-Phil...item1e8e17e9c8

That seems to be a deluxe kit.

http://www.ebay.com/itm/SAMSUNG-Phil...item1e8e17e9c8

That one only states contains 6 mosfet's--and does not state which ones.

On the right side of the board is a row of very large red capacitors. Behind them are a nest of RJH3047. Anyone know if these also are prone to failing? I don't mind digging them out to test.

The rest of the testing will have to wait. I have the two blown parts off the board until I can order in either the 2 chips alone, or the repair kit. (And maybe more parts if there's a good chance the RJH3047's need to be pulled/tested/replaced)

With the two blown mosfets--Collateral damage--I know those two are blown. Sense I lack a schematic--Are there any other parts that are known to roast when these fail? Makes me wonder a bit due to the repair kits. One kit just contains the 6 mosfets. The other kit contains 11 semiconductors and a couple of caps.

Sorry if this seems a bit of a ramble.

[tw2005]

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

So have you spotted the surface FEt and tested that for short? So am i correct in saying you have 2 shorted 88N30W, the rest were ok and the 2Sk2837 is not short cct?

[Tedybear]

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

Have not done any surface mounted FET's for testing. (This is my first venture into plasma sets and there's not a lot of schematics for this.) If that is what you are asking. I can supply more pictures of the board parts if that would help id where/what to test. (granted it would take a while to get the uploads LOL... This server hates me)

1 known bad 88n30w

K2837--I triggered this doing a standard MOSFET test out of circuit. When I triggered the gate the drain kicked 'on' as expected with low resistance on the diode check. Then for some reason--and this might be normal?? The resistance crept up quickly until it was back to an open circuit. I figured I might have a finger where it shouldn't be for the test. So I held everything in a rubber clip--and it did the same thing.

The other K2837 acted like a normal mosfet should have. So I figured it's toast.


Now there is a row of red capacitors along side the heat sink on the right. Sadly my iron went *poof* with the tip roaching. Do these go bad, or are they pretty well 'safe'. From what I've found, the one kit addresses the row of mosfets along the same side of the edge connector that goes to the buffer boards. (That's the cheap kit) And the deluxe kit does all of them.

Just trying to do this and keep a budget in place.

The two blown capacitors, I have on order and they will be here tomorrow. I can afford to order in the cheaper kit from eBay and just replace the two bad parts--and hold the rest for future use. I can't really see spending over $50 for the deluxe kit. Considering I'll have to spring for a replacement buffer IC...This is quickly hitting what I can afford to spend on it.

S-

[freakaftr8]

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

I wouldn't be concerned with those red drop capacitors as they rarely fail. If a k2837 tests.with no short it's probably ok. what you're looking for is a MOSFET on the Y mainboard that is shorted as in 0 oHms. black lead on the middle leg red lead to each and leg if you get 0 ohms in either direction or even one direction I would suspect

[Tedybear]

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

I wouldn't be concerned with those red drop capacitors as they rarely fail. If a k2837 tests.with no short it's probably ok. what you're looking for is a MOSFET on the Y mainboard that is shorted as in 0 oHms. black lead on the middle leg red lead to each and leg if you get 0 ohms in either direction or even one direction I would suspect

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-

[tw2005]

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

I wouldn't be concerned with those red drop capacitors as they rarely fail. If a k2837 tests.with no short it's probably ok. what you're looking for is a MOSFET on the Y mainboard that is shorted as in 0 oHms. black lead on the middle leg red lead to each and leg if you get 0 ohms in either direction or even one direction I would suspect

I'm thinking along the same lines, this may be a very simple 88N30W replacement .

[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.

[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-

[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-

[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.

[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

[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.

[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-

[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

[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!

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.

[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-

[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)

[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!

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-