It seems that I have also hardware issue.
I measured voltages and found that cpu ok, ram also 1v, bios chip gets 3v if powered on.
What is missing is VCCGFXCORE_I
So i checked the power supply that is PU404 output on PL406 and there were 0V. Then I checked PWM_1A with osilloscope that comes into the PU404 and it is 0v and when power is pressed it is stready 1v. Other power supply PWM-s jump up and down like PWM-s should.
VCCGFXCORE_I has resistance 7.3ohm.
Does the VCCGFXCORE_I need to be created on power up or later? What could I check?
Kaar3l
Member
Last Activity: Yesterday, 03:31 AM
Joined: 12-28-2014
Location: P2X-3YZ
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Hello!
I bought a dead T480s.
At first when I tried to start it it did start with no picture and run for 15 sec and then shutdown. Pushed power button again and same cycle.
What I have tried:
1) Tried another bios from here. It did start take 0,4A and stay that way with black screen. Seemed that it doesn't do restarts.
2) Desoldered onboard ram resistors. Didn't have any effect.
Now it flashes 3 times light when power is inserted and is dead. Power button does nothing. Power button works when checking with multimeter and also 3V comes.... -
I received new cable and tv works like charm.Leave a comment:
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Opened the connector box. ​Checked outputs. A13V and GND is 12,8V so it seems good. I did measure B350V and B_GND and it was 0V so no output of 350V. Does the conenctor box give 350V from start or should I short PS_ON with something to run?
One component seems dusty and "hot", but everything else looks fine....Leave a comment:
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I have the tv with big oneconnect box. When I remove the cable from PSU there is no power coming to power supply.
I did try to measure with everything connected voltages. And where should be 13V there is only 1V.
I also did measure voltages in big caps up on my pictures and these seemed to have 0v with powered on or off. So I am thinking that if 1) The power from oneconnect box doesn't get to the board. 2) The oneconnect box doesn't give power?
Next I will measure the outputs from oneconnect box and from the input to the tv-s motherboard.Leave a comment:
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Samsung QLED QE65Q7FNAT only standby light
TV: Samsung QLED QE65Q7FNAT
PSU: BN4400940A
MB: BN94-12832K
I got the tv in spring 2024. At that time it started, then ran 60 sec and poweroff. Seemed like reboot issue. I didn't have time and room to check it in summer so I plugged it in and now the standby light is on. I press button on remote, standby light goes off and tries to start?. No picture or backlight on LCD. I thought about removing diodes like in this thread: [url]https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-tvs-and-video-sources/85793-samsung-qled-q60r-constant-reboot-issue/page2[/url]... -
I used some randon DDR3, but the laptop needs DDR3L. I grabbed a DDR3L and it is working fine. So it was a shorted capacitor. Thanks!Leave a comment:
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I now tested the board a bit.
I push the power button.
Lights come on, power light is on.
Screen backlight flashes for a millisecond and then all lights go off (board resets).
This is exactly the same with AC adapter and battery. Even disconnected screen and it is still same.Leave a comment:
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I misdiagnosed the short a bit.
The PL700 that I removed is needed in the circuit. The shorted capacitor confused me.
I soldered PL700 back. Now the board is trying to start and leds flash when power is inserted. When I push power button the board is trying to start but then reseting. I think it might be charging/battery issue.
The battery charge icon is flashing (like charging) even when there is no battery connected. I connected battery and it started charging battery. (confirmed with multimeter).
I'll let the board to charge the battery and then try to start with...Leave a comment:
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Power adapter: 1 original 1 aftermarket. Confirmed working on different dell.
PQ4 in:19,4V out:19,4V
PQ700 in:19,4V out:18,9VLeave a comment:
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Dell E7250 5V and 3V missing
I got a dell E7250. That was dead and when plugged in the charger light would go off.
I found out that PL700 was short. I removed it.
Then next I saw that some capacitor was short. Found that PC715 was short. Remove that and now there are no shorts in 19v rail.
Next I wanted to see if 5V_ALW and 3V_ALW were present and no there is no 3V or 5V present.
Could somebody help. I cannot understand from the schematic what chip does create 5V_ALW and 3.3V_ALW? -
Re: thinkpad a485 bios password
Sorry about serial.
Thank you!
I did the mod with autopatcher. Then soldered chip back. Followed the tutorial, it froze on going to bios screen. Soldered chip off and back to programmer. Programmed the previous unmodified dump and it then got to bios. (Y)
Did also 10$ donation.
...
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Re: thinkpad a485 bios password
Hello!
I bought dead A485. Removed USB-C port that was shorted and now it has bios password.
I did take off the bios chip and read it.
Could anyone modify so I could remove password?...Leave a comment:
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Re: 32LG2000 wouldn't turn on
I changed the NCP1396AG, nothing changed.
Leave a comment:
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Re: 32LG2000 wouldn't turn on
I did bigger pics:
[url]http://s254.photobucket.com/user/Kaar3l_2007/library/32LG2000%20-%20EAY4050440?sort=3&page=1[/url]Re: 32LG2000 wouldn't turn on<br /> ...3&page=1[/url]Leave a comment:
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Re: 32LG2000 wouldn't turn on
Just tested that, only 5V is present. 24V and 16,5V are missing.
I did a picture under light, hope it is ok....Leave a comment:
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Re: 32LG2000 wouldn't turn on
I tried unplugging inverter and then powering it on, and results seemed the same. I tried watching picture with flashlight, but didn't see anything.
But couldn't be a problem on the other side of power supply some small smd chip(NCP1396AG)?...Leave a comment:
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Re: 32LG2000 wouldn't turn on
Just tested and from 24V line comes about 0,3V, so 24V is gone also.
I noticed weird thing when measuring the voltages, if I bent slightly the board, then a quiet buzz noise was coming out of that transformer....Last edited by Kaar3l; 01-01-2015, 07:21 AM.Leave a comment:
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Re: 32LG2000 wouldn't turn on
Changed optocouplers and didn't change the problem....
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Re: 32LG2000 wouldn't turn on
Could you give me some more hints, I haven't checked that before?
...
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