Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights
That's incredible news, actually! Glad to hear that it didn't require any replacement parts. Thanks for reporting your solution back here.
heathloder
IT Enthusiast
Last Activity: 11-11-2022, 08:14 PM
Joined: 03-17-2014
Location: South Kingston, Rhode Island
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Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights
Hi Edmusic. My assistance won't be nearly as helpful as the others on this forum with more experience, but I can at least offer similar insight to what was offered to me.
Realistically, the diode was not the first suspicion for failure on this TV. Without pictures of your boards or measurements on the LED strings/main caps/LED drivers, there isn't really a whole lot of help that can be provided.
If you follow the steps from the beginning of this thread (i.e. start with post #2...Leave a comment:
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Re: LG TV sound no picture, boards replaced
Just came across one of these today (LG 43UJ6200) whose backlight was turning off immediately upon power on (flashlight test revealed it was the backlight and not the whole display).
LED tester revealed open on LED string number 2. Opened chassis - LED tester found one bad strip (2nd strip from the top on the "right" if you are looking at the LED's from the front). Checked each LED - only one LED was found to be open
Literally ONE LED preventing this beautiful set from booting.
Just wanted...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
I managed to find a good deal on the X/Y-main board on Ebay. Put the new board in, fired the set up, and it hasn't shut down in over 20 hours of use over 3 days. I'm a very happy guy right now.
FWIW, I pulled out the two IGBT's that I suspected were faulty (Q5000 and Q5001) from the defective X/Y-main, and they tested fine out of circuit (using a 12V power supply for supplying voltage to the gates), but I suspect that they wouldn't reveal their "imperfection" until their temperature was a...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
All thoughts are welcome! I appreciate any advice.
I will attempt to check this IC during my tests of the X/Y-main board. As much as I wanted to narrow down the issue, I'm considering just purchasing the repair kit from ShopJimmy, since it seems to come with three of those IC's (along with all the other transistors and diodes that likely cause issues).
I'm a little nervous that my tests at room temperature may not reveal the issue with the problematic component if it requires the higher...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
The model was difficult to read off of the chip, but after fooling around a bit with a flashlight and magnifying glass, I was able to pull off the following info:
S4427
219P I<symbol>R
H8071
The datasheet for this IC can be found here: [URL="https://www.infineon.com/dgdl/Infineon-IR4426-DataSheet-v01_00-EN.pdf?fileId=5546d462533600a4015355d60b491822"]https://www.infineon.com/dgdl/Infineon-IR4426-DataSheet-v01_00-EN.pdf?fileId=5546d462533600a4015355d60b...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
So I got the new logic board in. Inserted it and now the vertical lines are gone, but the TV still behaves the same as with the old logic board (display shuts off automatically after anywhere between 5-25 minutes with the logic board LED going into a 5s ON/2s OFF flashing pattern).
In the time I was waiting for the new logic board, I spent a lot of time isolating the temperatures as best as possible on different boards. Regardless of which logic board I have installed, I can keep the TV running indefinitely...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
Unfortunately, it looks like I was wrong. I tried re-flowing the BGA chip on the logic board after applying some flux, and now the display shows thin white vertical lines, evenly spaced about 1-inch apart all the way across the screen. The TV still shuts itself down after some random amount of time between 5 and 10 minutes if left to run.
I ordered a replacement logic board, since I probably irreversibly damaged this one, but now my attention is on finding the culprit that keeps causing the display...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
Okay, so after hours of scouring the web and trying things out, I think I've finally made some progress. If I followed your hair dryer tip earlier, I would have saved myself hours... On the bright side, I'm pretty positive my Y-Buffer and X/Y Main boards are in pretty good shape after all the time I've put into testing them (and seeing them at work when the display [I]does[/I] power on).
Long story short, I can keep the display on by keeping my thumb on the "primary" BGA IC on the Logic...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
I just checked Ve and Vsc on the X/Y-Main, and here's the readings:
Ve: 98.4 V
Vsc: -185.6 V
The sticker on my panel makes no mention of Ve, so I'm not sure what it's supposed to be, but the value for Vsc is spot on (expected -185 V). Both of these reading were when the panel was 'ON'/displaying.
Also, just out of curiosity, is it correct to say that none of the FET leg's should show continuity to GND? I found this YouTube video (which has nothing to do with my TV, but...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
Sorry about that!
Just measuered VS on CN804 while the bulbs were lit and it read 215.5 V, and the rated VS for this panel is 209 V (based on the sticker in the center of the panel on the back), so that looks OK to me.
I'm going to re-connect the other boards and see if I can get measurements from the Ve and Vsc test points on the X/Y-Main board. I only see one adjustment "screw" on the X/Y-Main, so I assume that's for Vsc (it's not labelled well).
I'll post back...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
I just made myself a 240V bulb by stringing two incandesents in series. I disconnected all connectors from the PSU, placed the bulbs in series across VS & GND pins, Jumped VS-ON to STDBY, and jumped PS-ON to GND.
Once I applied 120VAC, the light bulbs lit right up and continue to remain lit. I measured the following pins while the bulbs were lit:
[B]CN804:[/B]
D15V: 14.60 V
D5.3V: 5.26 V
VA: 58.5 V
It has been running for over 10 minutes...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
Not really knowing where to look next, I started doing some very basic and general testing on the X/Y-Main and Y-Buffer boards. I removed both boards from the TV and began with the X/Y-Main.
I tested the three MOSFETS and 2 diodes (in-circuit) that were attached to the heatsinks - they are the only FETs/diodes on the top-side of the board.
They all seemed to test OK (using the 'diode' function on my DMM).
[B]FET Q5001:[/B]
[U]Pin (-,+) | Reading[/U]
1-2...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
Yes. The TV requires no "cool down" time whatsoever, and when turned back on, will remain on for almost 5 minutes again before cutting out every time. Just to clarify, once the display turns off, the function button doesn't work anymore, so I must unplug and re-plug in the unit to effectively "reboot" it....Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
Thanks @diif.
I managed to get the self-test to power up, and it successfully cylced through the patterns about 5 or 6 times (~4 minutes) and eventually shut down just as before, exhibiting the same 5s ON/2s OFF LED pattern on the logic board.
Does this imply that the mainboard is [I]not[/I] causing this issue?Re: Samsung PN43E440A2F – display turns off after several minutes
Thanks @diif.
I managed to get the self-test to power up, and it successfully cylcedLeave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
So I've jumped the PS-ON connection on the SMPS to ground using the harness that was unplugged from the mainboard, as instructed in the fast track guide, but when I went to jump the test jig pins on the logic board, I noticed that I only had two pads, instead of four (or even six), as the fast track guide suggests I would find.
My initial though was that there are probably 4 pads underneath, soldered in pairs, but I have no idea what any of the pins do, except being told that the "highest 2"...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
Upon initial power-on, the logic board LED blinks for a half a second, every half a second (0.5s ON/0.5s OFF), which appears to indicate normal operation, and can be confirmed visually/audibly.
Once the display shuts off, the logic board LED starts showing a 5s ON/2s OFF pattern.
I've attached a page from a PDF I found that has some information about the LED patterns; not sure how authoritative it is.
I will attempt @diif's suggestion shortly (power/logic board test patterns)...Leave a comment:
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Re: Samsung PN43E440A2F – display turns off after several minutes
Thank you for your response @dick_barton!
I just probed CN804 while the TV was operating normally, and then again when the display had cut out. The readings were as follows:
[B]Connector CN804 (SMPS/X-Buffer):[/B]
[B]DISPLAY ON[/B]
Pin 1 GND =
Pin 2 PS-ON = 118.9 mV
Pin 3 VS_CON = 1.45 V
Pin 4 VS-ON = 3.27 V
Pin 5 GND =
Pin 6 D5.3V = 5.23 V
Pin 7 D15V = 15.28 V ...Leave a comment:
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Samsung PN43E440A2F – display turns off after several minutes
I have a Samsung PN43E440A2F 43” plasma that operates normally, with the exception of the display randomly shutting off after several minutes of running (approximately 5 minutes). When the display turns off, I continue to receive audio through the optical output to an external speaker, but there is no backlight and there appears to be no image either (using the flashlight test). The audio function doesn't seem to fail regardless of how long I leave the TV on. I'm using an external speaker because I don't currently have access to the TV's internal speakers (I left the speakers at the owner's... -
Re: Sony XBR-65X850E - has standby 3.3V, but won't power on - no status lights
Just wanted to provide an update to this thread after finally receiving my Schottky diodes in the mail.
Replaced D752 and re-soldered Q750A, and...
It worked! The TV powered on normally and booted up as expected. So, just to confirm, the issue with this TV was the 150V 5A Schottky diode labelled D752.
Thank you @nomoresonys, @R_J, @budm, @ngth82 and @brucetv for your assistance!Leave a comment:
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