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

[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 .

[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-

[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!

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-

[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!

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.

[reaper57]

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

From what I see in the posts, ymain and buffers are shot.

Post #1 One of the buffer chips went up in smoke.

Post #12 protection cct LED is illuminated

Post #14 Shorted 88N30W FETs

Bottom line, either replacement buffer and ymain or component repair of both

The ymain may just need replaced of the shorted 88N30W FETs. I got lucky with 3 TVs and it was just those, I do have one here (samsung)which has those plus the 2SK2837 is short along with the SMD FET STB20NK50Z TO263 17A 500V is also shorted. Also had blown PSU and shorted upper buffer ICs.

If you got the ymain going and managed to identify and remove the shorted buffer ICs, it may generate a picture on the balance of the good ICs . i have seen a video where someone had removed them and for a test produced a partial picture on what was left . Not something I've done and I have no experience replacing or hand soldering buffer ICs.

Here are two videos of me doing that (starting the tv with removed ICs).
First should be with some of the ribbon cables detached and the second with them attached.

https://www.youtube.com/watch?v=Va9j...ature=youtu.be

https://www.youtube.com/watch?v=GyTx...ature=youtu.be

P.S. My phone's memory was low so the video was glitchy so I'll add a photo.

[tw2005]

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

Yep that's gotta be it. Good detective work mmartell! since The OP has never seen the inside another plasma TV of course he would assume that they're all built with one modular buffer board instead of two separate.

Tedybear can you unplug the buffer board from the Y main and verify if you have a green LED representing protection mode on the Y main still?

if yes you need a new y mainboard or repair your existing if no you need a new buffer board or repair your existing either way you still need to repair the buffer board or replace

From what I see in the posts, ymain and buffers are shot.

Post #1 One of the buffer chips went up in smoke.

Post #12 protection cct LED is illuminated

Post #14 Shorted 88N30W FETs

Bottom line, either replacement buffer and ymain or component repair of both

The ymain may just need replaced of the shorted 88N30W FETs. I got lucky with 3 TVs and it was just those, I do have one here (samsung)which has those plus the 2SK2837 is short along with the SMD FET STB20NK50Z TO263 17A 500V is also shorted. Also had blown PSU and shorted upper buffer ICs.

If you got the ymain going and managed to identify and remove the shorted buffer ICs, it may generate a picture on the balance of the good ICs . i have seen a video where someone had removed them and for a test produced a partial picture on what was left . Not something I've done and I have no experience replacing or hand soldering buffer ICs.

[freakaftr8]

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

Yep that's gotta be it. Good detective work mmartell! since The OP has never seen the inside another plasma TV of course he would assume that they're all built with one modular buffer board instead of two separate.

Tedybear can you unplug the buffer board from the Y main and verify if you have a green LED representing protection mode on the Y main still?

if yes you need a new y mainboard or repair your existing if no you need a new buffer board or repair your existing either way you still need to repair the buffer board or replace

[mmartell]

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

Ok here is the source of at least some of the confusion in this thread. The OP appears to have this YBuffer board

http://www.shopjimmy.com/samsung-lj9...scan-drive.htm

So no upper/lower we were imagining and hence when we reference the lower buffer the OP naturally responds about the address buffers. Mystery solved lol.

So yes the YMain needs to be repaired and as freak points out the removed ic should be reinspected to ensure there are no shorts remaining. Then it's a matter of replacing the ic or the whole buffer board if all goes well up to that point.

[freakaftr8]

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

If I were you the first thing I would try is leaving the lower buffer board unplugged and see if you get the top half of a picture with just the upper connected. when you remove that buffer ic there's always a slight possibility that you at got sold er flashing between two of the Power Data pins they go into the bus I see I've done this myself a few times and it gave me a false representation that the main y board was bad when it in fact was just shorting due to the buffer board problem. you should have a top half picture with data being fed to it the data has to go through the upper buffer board before it can transfer to the lower.

also I would test all mosfet transistors on the Y main board. I have seen these boards have a multitude of different problems associated to blowing buffer ICS

I'm also still a little confused is there to buffer boards in this set or is there one long one extending from the top to the bottom of the screen? Could you take a picture of the full buffer board from end to end?

[mmartell]

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

Actually if you stick around you will find the guys here to be extremely helpful. But one thing they insist on is to be able to see what they are dealing with, as obviously they don't have the set in front of them like you do.

What is the part number on the YMain ? If iit's a Samsung board it will start with LJ41... The green light means Protection Fault as evidenced by the blown mosfets. This is a common fault on these. Shopjimmy sells a kit (used to anyway) for about $40 for this or you can source individual components.

If you do a search here for HPT5054 you will find alot of info that will be at the very least similar to what you are experiencing.

[Tedybear]

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

FAIL. A little advice - slow down and READ what people have to say, they are after all taking the time to respond to your questions.

As I stated in my previous post a lit green led on your YMain means it is in PROTECT mode because it has failed and needs to be repaired. Running the set this way with the buffers installed may destroy other buffer ic's.

And post some pics please, you have everybody confused about the damn hardware in this set !

I've already pulled two blown MOSFETS from the board and am in the process of researching two more part numbers.

Last few times I've went to post pictures on this forum the server quit responding, so I've had to post 2 to 3 pictures at a time...and do it in tiny steps that takes me a LONG time and I have other things to do as well. So I do my best to describe what I'm seeing and posting pictures of just the items I am working on.

So I just took about 20 minutes out of my day to upload a few photos to save confusion.

Another post regarding the Phillips using Samsung parts is that a lot of the "Samsung Rules" may or may not apply. So when I double checked the green light I removed power and disconnected the ribbon cable. Powered up and the green light was NOT lit. Reversed the process and turned the set back on--the green light then lit. So it might also make sense that the green light could point towards having a data stream from the CPU board, and that if the light is NOT on--then it could be missing the signal. This is due also with consideration of where that light is, which is 1/2" from the ribbon cable.

The two parts that I found bad, K2837 (switches on and then bleeds back to full resistance within seconds. Not typical behavior when compared to others of the same part number) and 88N30W (blown, no switching action and source/drain dead short)

I'm still trying to further research: RJH3047 (Looks like a normal transistor, but can't find a decent data sheet for it) And STTH20P035 Which doing a search of the forum yielded results and helped explain what it might be.

One of my questions was regarding the voltages coming from the power supply board to the supporting hardware. To ensure the power supply was working at 100%.

I've already given up any hope of reselling this set and am trying to learn from it, and even attempting to do surface mounted parts once I obtain the correct part(s) and tools.

On a more personal level:

I spend about 15-20 hours a week on several automotive forums assisting members with repair questions and maintenance issues when not doing my full time job. That's actually on 3 different groups for VW, Ford, and one for general service. I learn as much from the other members as they learn from what I know. The forums are very polite and people are eager to respond to lend a hand or encouragement for the "newbees".

And then you have this group..

I've seen some new people post here and they get mowed down pretty fast. Or they just get flat out ignored. I freely admit that I have not worked as a professional electronics tech for over 25 years. My role as "Tech Manager/Store Manager" for the last 20 years is mainly power supplies, and figuring out which internal board failed and then a swap with an advance replacement--and our own service dept gets to do all the repairs.

So I do read a lot of the posts and try to figure things out and 'read along' It helps me to rebuild my understanding and knowledge base. But you might want to really relax. Take it from someone that already has dealt with both a severe heart attack and open heart surgery 5 years ago..and cancer more recently. Life is way to short to get all hyper because a fellow member didn't quite understand something fully.

I'd like to work with the group and resolve this and increase my understanding and get a working set at the end of the process. However if all I'm going to get is dumped on for my efforts and get snarky comments in return? I'd rather just part the set out and take my leave.

Ya'll have a good night.

S-

[mmartell]

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

The green light on the Y board is lit and not flashing. (The board doesn't mention what that means--but I take it as a good sign that the circuit is getting voltage.

FAIL. A little advice - slow down and READ what people have to say, they are after all taking the time to respond to your questions.

As I stated in my previous post a lit green led on your YMain means it is in PROTECT mode because it has failed and needs to be repaired. Running the set this way with the buffers installed may destroy other buffer ic's.

And post some pics please, you have everybody confused about the damn hardware in this set !

[Tedybear]

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

I'm lost.

There is nothing I can see on the screen as far as any 'glow'.

I checked the X-board and it seems okay without cold solder joints and the fuses are good, same for the Y-Board.


Voltages: (All measured using the GND at each connector)

To the X-Board:

14.07dc is the VC
205.00dc is what is on the VS line

To the lower buffer board(s):

62.8VDC
5.2VDC

To the Y-Board:

14.06VDC
205VDC

The green light on the Y board is lit and not flashing. (The board doesn't mention what that means--but I take it as a good sign that the circuit is getting voltage.)

The only spark of hope that I do get? Is when I pull the plug I can hear the audio 'pop' LOL. So Yeah I'm hanging onto that as a sign of hope.

S-

[Tedybear]

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

I think he said that they are 2. The boards and plugs look like the ones on a Samusng plasma I repaired last week (PS-50Q97HD). If they are similar they should be two buffers attached to each other via a weird flexible bridge.

There is the one long buffer board on the left side directly attached to the Y board. It has 12 buffer chips.

The board on the lower side is the two long boards with the wiring pigtail connector/bridge. (Sounds very much like the one you repaired)

I currently have the Y board out so I can inspect it for cold solder joints. I can reinstall it and fire it back up. I might wind up relocating this in my 'office' so I can get around 360deg's. My bench is against a wall and it's a rather large object that's hard to work around. I'll get my face up to the screen and see if I can view any 'glow' once the board is back in.

[reaper57]

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

I just don't understand you exactly, how many buffer in your panel? One buffer or upper/lower combination?

I think he said that they are 2. The boards and plugs look like the ones on a Samusng plasma I repaired last week (PS-50Q97HD). If they are similar they should be two buffers attached to each other via a weird flexible bridge.

[ERICSSON89]

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

I just don't understand you exactly, how many buffer in your panel? One buffer or upper/lower combination?

[tom66]

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

Can you check carefully in a dark room and see if you get a subtle glow from the panel?

[Tedybear]

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

Ok Shopjimmy says this is the Samsung variant which means it has an upper y buffer as well as what looks like the lower buffer in your pics. If you install a good upper buffer and a good y main you should get a pic on the upper half of the screen. There is a youtube vid on how to test the buffers for shorts, maybe someone will post the link for you.

If there is a green led lit on your Ymain then it will need to be repaired as well. Keep in mind that bad buffers will destroy a good Ymain and vice versa so it's imperative you know the condition of these parts before proceeding.

That's why I was asking what to expect. I found the video about testing the buffers for shorts. Sure enough the one that went "Boom" had several lines with snorts and shorts on that one buffer chip. The rest tested okay using the multimeter quick and dirty method.

I carefully removed that one blown chip. Managed to have only minor damage to one solder pad and I think it's saveable. (small small jumper should do the trick, just need to update my soldering stuff....or see if I can solder pad it like I've had to do in the past for slightly larger stuff)

At any rate. With that chip removed, I still get 100% nothing on the screen. The rest of the buffers get hot to the touch, but not the "Let's blow off the board" kind of hot. Sense I do not know how warm these should run, I'm guessing.

Yes the lower board is present, it's a 2 sectional type that is covered by a metal shield. No smoke and such from there.

I did locate another **grrrr** blown capacitor on that board. 25volt 680uf made by "SanWa" I found an electronics company in the NYC area that had a 10 pack with the same specs by Rubycon for about 7bucks with free shipping. But honestly--Even with bloated capacitors I would imagine I would see something on the screen--probably garbage, but there should be something. It's just "Blackness". The only time I did see something? Was when the chip was blowing. And it was just a thin area of flashing white dots in the same area code as the chip.

I really can't invest to much more $$ in this set. I only paid $30 for it, and the power supply cost $45.00 to repair. ($25 for the cap kit, and $20 for the voltage regulators that where bad. It would have been cheaper, but the local supply house has a $10 charge on any order under $50 bucks. Call it me being impatient, but I wanted to see if my labor worked)

At least the PFC and the 5vo errors vanished. So the power supply board is back to 100%. All the other dodad's and green light flashy things are lit up. And the blinky light on the CPU board flashes)

Just wondering why I have zipola for a picture. Looks like everything should be having an effect. So I have to consider what would cause the entire screen to remain dark. Kinda removes one single part that effects a small section--Need to chase after a part that would roach the entire picture.

Replacement or ordering in the boards isn't really possible. I do this in an effort to better my lacking skills, to keep these out of landfills if possible, and to at least make a few bucks profit. Investing anything more really wouldn't make sense.

Kinda wonder if I should just cut my losses and sell the boards---less the Vscan boards on eBay and call it a day. Then the other part of me wants to see this through and figure it out.

So I'll ask my question--what would cause the entire picture to be 'dead'..the buffers to be warm and the heat sinks to be warm---so it's doing something. But it's a black screen. What is common to the 'whole' that would tank it. We do have good voltage to that board. At least I think it's good. There's no specs listed on the system to state what it should be.

Other question: Would a bad MOSFET be the reason the buffer chip blew up? There's enough of the flippen things on this board.

The capacitors being domed in my opinion shouldn't be the reason for a no screen--garbage on screen yes....but shouldn't kill off the whole thing. Is that a decent assumption on my part? Or should I just wait until the new caps come in and see.

S-