Re: 12V rail is not on ?
My DMM is autorange
My DMM is autorange
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Re: 12V rail is not on ?
I can see 2N60 on the PCB, I unsoldered it, but can't find it in the schematic ??Comment
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Re: 12V rail is not on ?
Ok...so most likely SB1040 because I tested on diode mode only 0.1V...too low...
I'll change three of 'em anyway to SB3040....
Meanwhile I'll check other transistor..
I'll keep posted..Attached FilesLast edited by bianchi77; 07-22-2016, 05:40 PM.Comment
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Re: 12V rail is not on ?
I have checked all the transistors and diodes, they are in a good condition...
so only these three diodes are under the normal condition...
how do you reckon guys...?
No problem with the capacitor as well ?
How about the chip ? U1,U2,U3 ?Comment
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Re: 12V rail is not on ?
and D7 is weak only 0.2VComment
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Re: 12V rail is not on ?
is U3 = ULN2003, darlington array ?Comment
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Re: 12V rail is not on ?
D7 should be the same as D9. I don't see any U3. The IC's you cant test most of the time. They either work or don't. An oscilloscope comes in handy with that.Comment
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Re: 12V rail is not on ?
U3
2003
down on the bottom of the schematic, connected to PS_ONComment
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Re: 12V rail is not on ?
Had the wrong schematic up. U3 is the PWM. Look at "PWM of the year"
https://www.badcaps.net/forum/showthread.php?t=35007Comment
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Re: 12V rail is not on ?
Do you know where we can find that chip ?
I tried googling it and can not find...
or the similar chip with that one ?Comment
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Re: 12V rail is not on ?
Why do you think the PWM is bad? you got any voltage on the secondary's besides STBY power, when you jump STBY to PSon?Comment
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Re: 12V rail is not on ?
I can't check the voltage because I unsoldered the rectifier for them...
I suspect 2 SBL1040 are bad....0.1V only on diode test...Comment
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Re: 12V rail is not on ?
Not shorted...and the diode for 12V rectifier is only 0.4V so I need to replace it as well....
waiting for replacement, I want to replace them all with SBL3040..Comment
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Re: 12V rail is not on ?
I test D22,D20,D17,D18 in circuit with 9V and LED,1K ohm....something is not normal...
It's on a both side of test reverse and forward bias...
Are they all bad ?
or to be sure must be off circuit ?
PCB code Y-B200 ATX Ver 2.6...and they are on 12V and 5V rail...Comment
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Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: 12V rail is not on ?
https://www.badcaps.net/forum/attach...4&d=1469140301
Look at the diagram, you have load resistors in the circuit, all you have to do is looking at how the current will flow when you hook up your 9V, 1K, and LED to the Diode you are testing then you will understand why the TEST LED will light up in both directions.Last edited by budm; 09-08-2016, 11:06 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: 12V rail is not on ?
https://www.badcaps.net/forum/showth...t=55771&page=2
Are the two jointed legs of the sub diodes touching the heatsink? How are all 3 legs connected to the board?
NEVER MIND, you changed them to something else.Last edited by budm; 09-08-2016, 11:09 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: 12V rail is not on ?
I've taken the four diodes of the circuit test it with LED and they are normal...must be something else....could it be PWM chip 2003 ?Comment
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Hello everyone,
I'm trying to repair my old Acer Nitro 5 (AN517-54-55T5). I've already bought a new laptop, so this is more of a learning project. For the experience, with no high expectations of success.
Well, my decice specs are the following:
Model: Acer Nitro 5 AN517-54-55T5
CPU: Intel Core i5-11400H
GPU: NVIDIA GeForce GTX 1650
Motherboard: GH51G LA-L181P Rev:1c
The symptom:
When pressing the power button, the power LED lights up for about 5 seconds and then turns off. Initially, the issue was intermittent: sometimes...05-26-2025, 10:49 AM -
Hello,
Have an Xbox One S here that has a short on the 12V power rail. There is no power, beep, or partial fan spin when connecting power cable.
After diagnosing with thermal camera, Q9F1 MOSFET (NTTFS4C50N) is getting hot. When I remove this MOSFET, the short on the 12V rail disappears.
I first replaced Q9F1 with one from a donor board and then partially reassembled the Xbox to test. When I plugged the power cord in, I got a partial fan spin and I thought I had fixed it, but unfortunately, the Xbox still did not power on. So I then disassembled the Xbox... -
Hello everyone!
This grafic card came for repair, but when I connected it to the motherboard, the board would not start (short circuit in the 12V rail).
After removing some PLs to isolate the short in the 12V rail, I got to PML1/PML2, according to the BoardView reference.
Even injecting a voltage of 1V0 and a current of 3A in the FBVDDQ rail, for example, the voltage drops to 0V20 and none of the components heat up.
The attached boardview file is very similar to this grafic card, which I am basing the repair on.
I would like some...05-10-2025, 09:19 AM -
Hi all.
This notebook was showing no signs of life.
I removed the FH52M LA-J891P mainboard and found that there was 19V at the DC jack.
However there was zero volts on the two PRB2 and PRB46 resistors immediately after the two polarity protection MOSFETs (PQB11 & PQB12).
If I remove the PQW1 MOSFET, the 19V rail starts working, and I can turn on the unit - at least I get the fans, and the power light comes on, when I simulate the power button being pressed. No display.
I tried replacing the MOSFET with a new one, but again no voltage on the... -
Hello,
first of all I want to apologize for my bad English, but I try to give my best.
Customer brought me a laptop, which is charging the battery (when the dc-jack is connected) but don't power up when the power-button was pressed down. Only the white LED lights up, and you can hear a short noise in same interval when power-button was pressed and hold for longer timer. The customer changed already battery and dc-power-adapter.
For this laptop the correct shematic is the service manual "Clevo NH50ER NH57ER NH50EPS NH57EPS - 6-71-NH5S0-D02 Schematic"....
Comment