Re: Samsung UN55KS8500 - previously power-cycling, now vertical colored bars
Hi
First, can you remove the back cover and take pictures of the TV set, the power supply and the main board!
kgavionics
Senior Member
Last Activity: 07-16-2024, 03:49 PM
Joined: 04-24-2017
Location: Western Canada
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Re: Sharp LC-50P66U-completely dead PSU!!
It looks like the mainboard, is not sending any signal back to the PSU.
By the way, this set is poorly designed and even though is branded SHARP, it's actually a Chinese crap made by Hisense!...Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
hello Budm and thank you for your help it means so much to me!
I think it was my error for not getting the 16V and 12V!
Regarding, the voltage reading requested in #21 I was getting 18.3 and a fluctuating 12V.
Yesterday, I was contacted by the seller of the card, who is a TV repair technician. He's a super nice guy who offered me to help, he asked me to take the measurement across the backlight connector, which I did, I only was getting 1V or so! I removed the power for 15 min. After that I went to check the 12V and 16V,...Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
I didn't change anything, but somehow I got the 18.3 on the 16V rail, a fluctuating between 8.3 to 12.3V 12v rail, but no standby voltage!
When I press either on the power button or the on remote nothing happens the pin SW doesn't go high. I guess it's normal, because the main board needs the standby voltage to be present to work properly?...Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
1-Yeah, the booster circuit is working fine
2-I have a fluctuating voltage between (112 to 123V) on the anode and (223 to 240V) on the cathode of V905.sorry I made a mistake earlier by saying I had 245 on the anode. I tested the diode and it's good, but how come I have a 100V drop across v905?
3-i'm 100% sure that I have 0v on that connector.
4-how can I take the measurement from the bottom side of the board? Do know a safe way to do it?Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
i have attached the top and bottom pictures of the old board....Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
I received the power supply board today, but I have the same problem! No output voltage or whatsoever, even with the backlight and main board connectors disconnected!
I have 388V across the main capacitor! And I have 245V on v905 anode (backlight)
I don't think that the new PSU is faulty either, according to the seller it was pulled from a broken screen TV!
To be honest, I never came across a problem when I don't have any output voltage!really weird problem!!Leave a comment:
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Re: Sharp Aquos lc-46le810un-Intermittant fleckring!
Problem never appeared after deactivating the ambient light sensor. Thank you very many guysLeave a comment:
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Re: 50uh5500 LED Strip LED type
I have the same tv with the same problem that i bought it for cheap, i ordered a set of backlight from aliexpress, before i even troubleshoot the tv, because this tv model is known bad backlight strips.hopefully,it won't take an eternity to receive them!Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
Thank budm! I ordered one eBay for $25!...Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
Yeah! I'm 100% sure that the IC is faulty, because even I replaced the V802, I still have 165V on the main cap, which indicates that the booster circuit is not working!
I looked on eBay for replacement board and I ordered it, but soon realized that even though it has the same part number it's missing some components which may indicates that the board is not 100% compatible with mine!
[url]https://www.ebay.ca/itm/BEST-BUY-SHARP-TV-LC-43LBU591C-POWER-BOARD-RSAG7-820-6666-ROH-HLL-4155WF/153828394846?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649[/url]...Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
I checked PIN2 and hot ground and didn't find a short!so hopefully, the IC is not burnt out!
I checked the value of the R825 on my USB microscope and it's marked 471 which is 470ohms!
I'm going to report all my findings after I replace the resistor!
Thanks again Budm!!...Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
Hi
I checked the R825 and found 220kohms, so I'm going to replace it and report back!...Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
Sorry, I forgot to mention that while I was troubleshooting the set I accidentally shorted V802 drain and the source which burned the R 826 resistor (0.1 ohms), but I replaced it with a 0.17 resistor and tested the Mosfet V802 and it was fine! Could it be the reason why I don't have the 380V?...Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
Thank Budm for your input! It's really appreciated!
I'm still trying to find what's going on with this PSU! But, I'm a bit stuck, because I didn't do any modification, but I'm only getting 170Vdc on the PFC cap! Weird!!Leave a comment:
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Re: Sharp LC-50P66U-completely dead PSU!!
Update: I found the PSU schematic!...Leave a comment:
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Sharp LC-50P66U-completely dead PSU!!
Hi guys
I just got this TV which is completely dead, not a single sign of life!
I have not a single voltage on the output of the PSU!
I checked the fuse which it was ok, I have 385V on the main Capacitor, beyond that I have nothing. The Mosfets and diodes were checked and tested ok (I might have missed something out). I'm still troubleshooting, but I'm open to your suggestions!
I didn't find any service manual or the schematic for the power supply yet, I just attached some pictures of the TV.
Thanks in advance...Last edited by kgavionics; 07-18-2020, 12:25 PM. -
Re: Toshiba 32av5000u-help identify resistor
the guy was lucky, because I think, he only replaced the cap thinking it would fix the problem, and since the Mosfet was shorted out and obviously the fuse is open it didn't do anything!
Nowadays, I see more people who don't have any knowledge about electronics and electricity who try to repair their TV's and this can be fatal sometimes!
My advice to all people who don't have any knowledge about electricity, don't play around with high voltage it can cost you your life!...Leave a comment:
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Re: Samsung LA32R81B Not Turning On
Have you tested all the diodes and Mosfets on the 12V and 24V rails?Leave a comment:
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Re: Insignia NSL-42Q-10A no power!
I really appreciate your suggestion, but the board is heavily damaged, I have found a lot of burnt small IC's! I have some other TV's to work on. This card is beyond economical repair!...Leave a comment:
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