Phillips 50pfp5332d/37 power board shot?

[Tedybear]

Hello again.

So I've been having some luck fixing the LCD sets. The Magnavox one hooked up to my PC purchased for $15 bucks. Had the 2 seconds to dead. Took it apart and it fixed itself, but the PSU had capxon blown top capacitors that got changed for safety. Burning it in for a few weeks before I put it back on the market.


At any rate. Picked up a Phillips 50" Plasma with the model number in the title. Guy stated it had a bad power supply board. Yeah, it's bad. It has several capacitors with domed tops and even some yucky leakage from one. The 5volt standby line has only 0.430 vdc on it. And the small board is flashing "7" (or 7 flashes in a row...pause....then 7 again)

So yep, caps are in line to be replaced. Just wondering what other surprises I should expect from this set? First time working on a plasma, and am pretty excited to see it through.

Pics are also included for your viewing pleasure.

It's a lot of photos, but I wanted to ensure we have all the info needed.

I'm probably going to order in the cap kit off ebay. I found a local supply house, but unless I want to shell out $50 per order, I will get slapped with a $10 handling fee.

http://www.ebay.com/itm/Philips-50pf...item35cc429e2a

$25 for the kit? Reasonable? I'm not sure. I'll source out the caps with the local shop with the handling fee...

Thanks for any help and advice!!!

S-

[Tedybear]

Re: Phillips 50pfp5332d/37 power board shot?

Ordered in the kit from the gentleman from CA. He seems a decent sort and knows of this forum quite well.


Just a couple of details:

We do have 5volt Stand By.

We do NOT have any 12volt Stand By.

The Tv when the power button is pressed, goes 'blue' and then flashes 'red'. The small board on the power supply board flashes the 7 flashes with is PFC. Did we get any resolution on what that means? I did find some open threads, but no real answers.

Thanks again!

[Tedybear]

Re: Phillips 50pfp5332d/37 power board shot?

Minor update. Played around with the power supply while waiting for the cap kit.

We had 5 volts for a short while. The 12vdc is present on the pin, but buckles under load. With everything plugged in--The board would just go 'click click click click'.

So when I unplugged the connector that sends the 12vdc to a smaller board that is kinda tucked away- The power supply board came to life. with no error codes on that mini board.

Now it's to the point where with everything unplugged, except the A/C- The mini board is flashing a code for the 5 volts (6 flashes) and the board clicks 'on...and then clicks off a moment later. And it continues to flash the error 6.

Anyone have any ideas here...or just throw the cap kit at it and see what happens. I'm a bit amazed that the P/S did start to function--and now has totally taken a crapola.

I'm kinda getting the feeling I'm flying solo again. The board itself is coded: PS-507-PHN and I'm to understand it's a special order by Samsung that made it--for Phillips.

**hearing crickets**.....no ideas?

S-

[Tedybear]

Re: Phillips 50pfp5332d/37 power board shot?

Still hearing crickets. Kinda depressing.

I'll continue to talk to myself :-) I love a good conversation.

I did the full recap of the power board. Surprised at how fast I'm getting at this.

Still the power supply board tanked with the flash code for no 5 volts. So I (without having a proper schematic) started to back trace the 5v switch line back all the way. And finally I bumped into the caps I just replaced (there's a shock) And then a nice little part with the number:

33167T Seems this little gem is a very advanced setup for a 5volt switched regulator. And lucky me :-) There's a matching one a few spots down on the heat sink for some compare readings.


The one in question is labeled on the board as a U8401

I'm guessing one of the bloated capacitors may have done a number on it. Can't really tell. No serious schematic that I can find for just that power board.

Anyrate. I poked around and started testing across the pins of that part. And comparing results to the sister one on the board. Found that when I read resistance across pins 2 and 4? I wind up with just about a dead short.

Pins:

1= Voltage Feedback Input
2= Switch Output
3= Ground
4= Input Voltage Vcc
5= Compensation/Standby

So with the output shorted out for the Input Voltage? I think the overload protection/overvolt protection is being triggered on the safety board and it's flashing the 5v light code. (Where as before it was doing the power fault code (pfc))

If I'm understanding how a very basic regulator works, it takes a slightly higher DC line (probably 12volts) and knocks it down to 5vdc. If the input and output are shorted out--then it would trigger the error.

I checked things out by unsoldering the 2 and 4 pin on both semiconductors and making sure nothing was hitting a solder pad. I then did a basic diode check and the suspect one read 0.046 both directions. The one that I think is good? Read about .568+ Without having a schematic to work with, I'm flying blind. However the fact my meter on a continuity check beeped on the suspect one across pins 2&4. And did NOT beep on the sister chip? I think I just found my issue.


Question is? Is that the only part that needs replacement. I'm going to order a pair of these buggers in and probably replace them both. One is clearly bad--So it might be worthwhile to replace 'em both and see what happens.

Feedback, ideas, sharing popcorn???

S-

[tbrooks]

Re: Phillips 50pfp5332d/37 power board shot?

Hey, I'm new here and do not know much more than the crickets do yet, but sounds like your on the right track. If you could only find another chip to test for certainty. I guess you'll have one soon. I see no reason to order 2, but might be good to have an extra (or maybe more) incase an unforeseen problem has caused the chip failure.

[Tedybear]

Re: Phillips 50pfp5332d/37 power board shot?

That's what I was thinking when I order them in. With 2 matching chips on the power board at least it gave me something to compare with. So it really could be one or the other that is defective. Most likely the one with the 'short' causing an over-voltage. I've found a local supplier for electronics parts, and another possible one in Syracuse.

I was weary about using the local one. They do not have a 'store front' just a warehouse that allows for local pick up. It's a $10 fee for just pulling parts that total under $50 bucks. Granted I can probably come up with $50 bucks worth of crap to buy, but don't have the funds for a massive order.

I'll continue to poke around. My gut feeling is that the chip was probably overloaded/stressed or something. Maybe from the blown capacitors that just got replaced. At least I hope so. Without any schematic for this board, it's flying blind and guessing.

S-

[Tedybear]

Re: Phillips 50pfp5332d/37 power board shot?

Power board is all fixed and happy.

And of course, it blew a chip out

The board that had the critical fail? LJ41-05377A

The chip that went "Poof"? 3289F

buffer board IC 3289F

So my clear question? What would cause that chip to go boom?

And would I be better off parting out the boards and calling this one.

Looking for help here guys. On the board it's labeled U5504

S-