bradcaps
Member
Last Activity: 04-04-2025, 01:03 PM
Joined: 01-11-2019
Location: Madison
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Troubleshooting Optiplex 3080
Hello people,
Our service bay had what appears to be a stereo amplifier that went on the fritz and fried two Dell Optiplex 3080's that were plugged into the same UPS. I never seen such a situation.
Anyways the computers do not power on. A replacement power supply didnt resolve the issue when this occurred a few years ago. I want to try to revive one now.
I plugged the faulty computer into a 40w and 60w dim bulb, which flashed several times before it stopped without any power button interaction. The green LED lite on the PS then went dark afterwards. The PS... -
Re: Samsung UN60J6200 No power up
Ok the backlight is working. But I maybe messed something up. I did accidentally make small crack in a corner
Chalk it up as a learning experience....
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Re: Samsung UN60J6200 No power up
Installed new backlight LEDs. With panel disconnected from microcontroller, on dim bulb, the backlight lights up, but only momentarily as it flashes on and off every few seconds. The bulb remains is dim in this case.
With panel attached to microcontroller the dim bulb flashes bright after the flash of the backlight. I do see blue LEDs light up on the TCON board now but only momentary before backlight flashes off.Leave a comment:
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Re: Samsung UN60J6200 No power up
TY, that seller sold 130 units, must be decent quality. Ill give it a try and report back....Leave a comment:
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Re: Samsung UN60J6200 No power up
Can you post the part number for replacement. Thank you....Leave a comment:
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Re: Samsung UN60J6200 No power up
Fired it up on a 100w dim bulb tester, bulb flashes bright then dims every 3 seconds.Leave a comment:
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Re: Samsung UN60J6200 No power up
you maybe right. cant get it into forced backlight mode. Today I suddenly got reading of 100v on center pin of that mosfet and diodes under it. Power cycle, then i get 500mV. On one power cycle it didnt automatically turn on like it has been, i had to use the power button to turn on. this unit is acting erratically.Leave a comment:
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Re: Samsung UN60J6200 No power up
It looks like BLU_PWM is .9V, is this correct?Leave a comment:
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Re: Samsung UN60J6200 No power up
After closer inspection I do see video.Leave a comment:
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Re: Samsung UN60J6200 No power up
Here is board...Leave a comment:
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Re: Samsung UN60J6200 No power up
No go with heat. The CPU is warm. The optical is lit. Poking with chopstick did nothing. I may have overlooked LED now i see it when moving power joystick. When power on I now see 5 blinks then nothing. I hold in power button LED flashes repeatingly.Leave a comment:
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Re: Samsung UN60J6200 No power up
Good idea to check for cold joints. Will also try freeze spray.Leave a comment:
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Re: Samsung UN60J6200 No power up
According to this doc ps_on when off should be 0.2v, 3.3v when on. I am getting 4.3v A little concerning.
I am learning a microcontroller is used on these modern TVs to control analog ports such as like on an Arduino. This microcontroller controls the power LED. Either the microcontroller is faulty or its not getting power. We haven't found any anomalies with the power supply yet, 12v rail seems ok, therefore I suspect bad "main board" or microcontroller. I could diagnose it further if i had a schematic....Leave a comment:
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Re: Samsung UN60J6200 No power up
ps_on i read 4.46v with or without power button pressed.
two greys read 412v & 92v with or without power button pressed.Leave a comment:
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Re: Samsung UN60J6200 No power up
FDPF3N50NZ
[url]https://www.mouser.com/ProductDetail/onsemi-Fairchild/FDPF3N50NZ?qs=veu3GWUQAjPxOMyrciRkHg%3D%3D[/url]
Its a MOSFET not a regulator.
Pin 1 = 0v, pin 2 around 400mV, pin 3 a few millivolt.
Fault is perhaps more upstream.
I get 388v across each of the large 450v filter caps.Re: Samsung UN60J6200 No power up<br...> Its a MOSFETLeave a comment:
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Re: Samsung UN60J6200 No power up
Thank you i added more images with legends. The last image shows a large On/Standby voltage test point which i measured 12v at that point after simply plugging the unit in. This perhaps demonstrates that the standby circuit is faulty. The third photo shows the regulator outputting the 1v. Im going to measure if any voltage is going in to it....Last edited by bradcaps; 09-27-2022, 11:51 AM.Leave a comment:
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Re: Samsung UN60J6200 No power up
i am reviewing the troubleshooting lcd tv pdf from sticky. It says "The power supply has Standby 5vdc (5VSB, this is a MUST have before anything else will work,
when this voltage is not present, there will be no any indicator light on the front panel)"
This may confirm my suspicion. I am curious if the dead regulator i found is for the stand by power supply.Leave a comment:
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Re: Samsung UN60J6200 No power up
"Unplug the cable between the power supply and main board and plug the TV in."
Still Nothing.Leave a comment:
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Re: Samsung UN60J6200 No power up
As far as I can tell I have no standby LED, no backlight, no nothing. Its dead. Can the regulator i pointed out as possibly bad be part of faulty standby power? Are schematics available?Leave a comment:
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