Phillips 50" Plasma - 50PF7321D/37

**retiredcaps** · 02-23-2011, 01:33 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Radio Shack does not sell low ESR caps which are required in SMPS application. They sell general purpose caps.

A list of high quality low ESR can be found at

https://www.badcaps.net/forum/showthread.php?t=2280

**WinRyder** · 02-23-2011, 01:50 PM

Re: Phillips 50" Plasma - 50PF7321D/37

So if i replace the caps with these will it work? Is that what your saying?

**thelmores** · 02-23-2011, 01:52 PM

Re: Phillips 50" Plasma - 50PF7321D/37

I have access to the service manual if it helps any......., will have time later this evening to post parts if you need.......

If you need something, try to be as specific as possible.

**WinRyder** · 02-23-2011, 01:54 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Well i'm central time, its 1:54pm right now what time do you think you would be back on? Also i'm looking on the site(s) he listed for parts, alot to choose from...
but sure we can talk, i really want to get this working.

**thelmores** · 02-23-2011, 01:54 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Originally posted by WinRyder

So if i replace the caps with these will it work? Is that what your saying?

While you certainly want low ESR caps, I doubt that using general purpose caps would keep the TV from coming on.....

Short term, they would probably work, long term you would want to put some good caps in.......

**WinRyder** · 02-23-2011, 02:02 PM

Re: Phillips 50" Plasma - 50PF7321D/37

ok understandable, but in the long run it still didn't work lol

- the caps i put in it first -

**PlainBill** · 02-23-2011, 02:21 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Originally posted by WinRyder

Hi everyone my name is Jason, and I'm in need of help with this plasma tv i bought the other day. I've read though one forum on here that was created by PlainBill cause he had the same PSU but not the rest of the unit was. But sadly my repair training is limited (College got rid of the program...) Well I opened it up, took out the PS and looked at it and found 4 blown caps under a heat-sink (agrees with Bill on the crappy design) rated at 470uf 35v, easy i thought i have those on hand, removed the old ones, and replaced with new ones that we recently purchased from radio shack. put it all back in and turned it on and still nothing. Relay clicks twice (green light) and blinks red several times. I thought testing each other one on the board, but wanted to know if anyone has any info or idea what else could be the problem. I may not have pictures right now but I can find a picture online and circle on it where the bad ones were if need be.

Chassis # EP1.1U AA
MODEL# 50PF7321D/37
PSU # LJ44-00125A

How many blinks? The service manual is on Scribd. Page 25 lists the blink codes for when it goes into protection.

The first step is to replace the caps with good quality low ESR caps, then (if necessary), continue from there.

PlainBill

**WinRyder** · 02-23-2011, 05:47 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Ok out of the list of different companies, which should i get that are rated at 470uf 35v, i've only found (https://www.badcaps.net/store/produc...roducts_id=114)

**thelmores** · 02-24-2011, 08:02 AM

Re: Phillips 50" Plasma - 50PF7321D/37

here is another option......

http://www.mouser.com/ProductDetail/...DM6OpFSYm78%3d

**WinRyder** · 02-24-2011, 11:51 AM

Re: Phillips 50" Plasma - 50PF7321D/37

would it be a good idea to replace all of the caps with Low ESR?

**PlainBill** · 02-24-2011, 02:38 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Originally posted by WinRyder

would it be a good idea to replace all of the caps with Low ESR?

It's not a bad idea, but there probably are a lot of caps. What I would suggest is examining the supply carefully for any other bulging caps. Then replace the caps that failed with good quality low ESR caps (I prefer Panasonic FR, FM, or FC) and see if the power supply works. If it does, then make a decision on replacing the rest of them.

PlainBill

**WinRyder** · 03-01-2011, 06:39 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Ok, changed out the caps with the ones recommended, still nothing... I also tested the the other caps and all are fine. I've read from page 25 and down on the service manual and I don't understand 100% the procedure that needs to happen to let me know what the code is. Am I suppose to look at the front of the tv in the bottom left hand corner, or on the back where the psu is located?

**PlainBill** · 03-01-2011, 09:37 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Originally posted by WinRyder

Ok, changed out the caps with the ones recommended, still nothing... I also tested the the other caps and all are fine. I've read from page 25 and down on the service manual and I don't understand 100% the procedure that needs to happen to let me know what the code is. Am I suppose to look at the front of the tv in the bottom left hand corner, or on the back where the psu is located?

Error codes can be read three ways. One way is with an interface called Compair? that plugs into the service connector on the back. A second way is via the blink codes - the flashing red LED. The third is on the screen itself. Somewhere in the manual it describes shorting a pair of solder pads on the SSB to force the set into displaying blink codes.

PlainBill

**WinRyder** · 03-01-2011, 10:32 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Originally posted by PlainBill

Error codes can be read three ways. One way is with an interface called Compair? that plugs into the service connector on the back. A second way is via the blink codes - the flashing red LED. The third is on the screen itself. Somewhere in the manual it describes shorting a pair of solder pads on the SSB to force the set into displaying blink codes.

PlainBill

Way one - not able to do

Way two - the flashing red led on the front of the tv basically goes through this procedure. When plugged in you hear two clicks from the psu (guessing its the relay at the same time the led is green. After about a few seconds you will notice the screen attempt to come on (looks like a slight fuzzy flash, best way to describe it) then you hear one more click of the psu, and the green led turns off and then the led switches to red and flashes 4 times *pauses* flashes 4 time *pauses* flashes 4 times and repeats and repeats. At this time i'm unable to turn off the tv via power button or remote

Way three - nothing appears on the screen

**PlainBill** · 03-02-2011, 07:53 AM

Re: Phillips 50" Plasma - 50PF7321D/37

Originally posted by WinRyder

Way one - not able to do

Way two - the flashing red led on the front of the tv basically goes through this procedure. When plugged in you hear two clicks from the psu (guessing its the relay at the same time the led is green. After about a few seconds you will notice the screen attempt to come on (looks like a slight fuzzy flash, best way to describe it) then you hear one more click of the psu, and the green led turns off and then the led switches to red and flashes 4 times *pauses* flashes 4 time *pauses* flashes 4 times and repeats and repeats. At this time i'm unable to turn off the tv via power button or remote

Way three - nothing appears on the screen

Exactly - protect mode, Error 4. There is a lot of technical discussion on pages 25 and 26, but there are two approaches to take AFTER performing some preliminary tests.

The first preliminary test is the 12V supply - does it rise to a full 12 volts? If it does, you can either try checking the Small Signal Board (SSB), or just replace it. And THAT decision depends on your troubleshooting skills. I do note that the SSB is available on eBay for as little as $70, including one from a seller with 99.8% positive feedback.

Things to check on the SSB are the SMD fuses, the 3.3 and 2.5 volt supplies, and I2C bus 4. I'll be honest, if I had the TV on my bench I would at least determine where I2C bus 4 runs. There IS a distinct possibility that it runs to an IC that is unobtainable, or contains firmware.

PlainBill

**WinRyder** · 03-02-2011, 02:13 PM

Re: Phillips 50" Plasma - 50PF7321D/37

on the psu there is a spot that says 12V ssb and underneath that is a 5Vstb, after looking more at the board there are others ones, like D3V3, D5V, Va, 5Vsw, GND_SSP, 8V6

which of these should i test?

**PlainBill** · 03-02-2011, 02:41 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Originally posted by WinRyder

on the psu there is a spot that says 12V ssb and underneath that is a 5Vstb, after looking more at the board there are others ones, like D3V3, D5V, Va, 5Vsw, GND_SSP, 8V6

which of these should i test?

12V ssb. SSB = ssb = small signal board. Well, checking all of them would be a good idea.

The DC-DC converter in the upper left corner of the SSB takes the 12V ssb from the power supply and converts it to 3.3, 2.5, and possibly other voltages used on the SSB. Without those voltages the I2C bus (and most of the other circuitry on the SSB) would not work.

The objective is to have a high level of confidence that if you buy an SSB it will fix the problem.

PlainBill

**WinRyder** · 03-02-2011, 04:07 PM

Re: Phillips 50" Plasma - 50PF7321D/37

ok on the psu the, 12V ssb it get 0.03V and the 5Vstb gets 5.34V, please note this is from the psu so is it still the psu? at the way things are looking, the psu is still shot... or at least the 12V ssb on the psu and i did trace the wires for the 12V ssb to the ssb and still 0.03... any ideas now or should i just buy a new psu from ebay?

**PlainBill** · 03-02-2011, 04:53 PM

Re: Phillips 50" Plasma - 50PF7321D/37

Originally posted by WinRyder

ok on the psu the, 12V ssb it get 0.03V and the 5Vstb gets 5.34V, please note this is from the psu so is it still the psu? at the way things are looking, the psu is still shot... or at least the 12V ssb on the psu and i did trace the wires for the 12V ssb to the ssb and still 0.03... any ideas now or should i just buy a new psu from ebay?

Not yet. First of all, did you do the test while the TV was trying to turn on?

Test sequence:
Unplug the TV until the red light stops flashing.
Plug the TV in.
Connect the DMM to measure the 12V SSB output of the power supply - it should be 0 volts. Have someone turn the TV on. Note the voltage.

If it rises to 12V the 12V ssb section of the power supply is good.

If it rises to anywhere between 4 to 10 volts there is a problem with the SSB.

If it doesn't rise at all, the power supply is PROBABLY bad.

Buried somewhere in the service manual is a section discussing the DC-DC converter section of the SSB. The short story is it uses several mosfet switches instead of diodes to handle the DC-DC converter. This is a known problem, and repairing the SSB requires replacing three ICs; total cost under $10, the parts are available from Digikey. Check the parts list in the service manual, do not order the parts listed in the schematic. The parts list lists upgraded parts.

PlainBill

Phillips 50" Plasma - 50PF7321D/37

Phillips 50" Plasma - 50PF7321D/37

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