I have a backlight issue with a known good screen, video is fine on external, can see internal image on screen with flashlight. Think issue is with backlight control (p. 15 of schematic). I have voltage (3.3V) with machine running on pins 2 and 3, need voltage at pin 5 to have backlight, correct? Need to learn to interpret a schematic...
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Re: Acer M5-481PT backlight issue
List all the pins voltage.
This is the startJust cook it! It's already broken. -
Re: Acer M5-481PT backlight issue
Find u22 and list the voltage from there.
Aparantly this machine got led ic driver. Similar with those crap mac'sJust cook it! It's already broken.Comment
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Re: Acer M5-481PT backlight issue
And find u2 to
Get the voltage from there toJust cook it! It's already broken.Comment
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Re: Acer M5-481PT backlight issue
Go to kbc and find bl_on from pin 2.
See if its 0 to. Lift that resistor and check on pad if its 0 before u22 input.
The thing is this u22 its interconnected with kbc and we need to find out who is bad u22 or kbc fir not enabling the back lightJust cook it! It's already broken.Comment
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Re: Acer M5-481PT backlight issue
Check for short with groundLast edited by dj_ricoh; 09-16-2015, 02:12 AM.Just cook it! It's already broken.Comment
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Re: Acer M5-481PT backlight issue
BL_ON from pin 2 of U22 ties in to the backlight control circuit of Q16 (I searched the entire schematic and those were the only places that BL_ON was found) thru diode D8 to LID#. LID# also comes from the hall sensor and ties in. LID# then goes to pin 93 of the KBC, where I measured 3.3v. So KBC is ok? U22 no good?Comment
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Re: Acer M5-481PT backlight issue
Logical yes.
I'm thinking if its ok to give power without u22.
If you lift it up does the voltage come back?Just cook it! It's already broken.Comment
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Re: Acer M5-481PT backlight issue
Just take u22 out and check for short with ground on each pins.
If there is no short check u22 if its got short on pins via ground pin.
Don't apply power its much safer this way.Just cook it! It's already broken.Comment
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Re: Acer M5-481PT backlight issue
Nice.
I hope it works out.
From china?
Just cook it! It's already broken.Comment
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Re: Acer M5-481PT backlight issue
Changing U22 didn't help. It's now time to consider this motherboard isn't the right one for the screen. This board is not the one that came with the computer when I bought it almost a year ago. The original has a dead short which is gonna need to be fixed. Both boards have identical part #s and revision numbers but as you can tell by the pictures, they're different. The original doesn't have the U22 chip that I just changed, although the schematic matches the "new" board perfectly. The screen lit up fine with the original board before it died. Is that why this board will not light up the screen?Comment
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Re: Acer M5-481PT backlight issue
Forgot pictures in previous post againAttached FilesComment
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Re: Acer M5-481PT backlight issue
what voltage you got on Q16?
that zone its super hot.
something missing there it does not trigger the BL.
check all resistor and diodes.
you even got a transistor hooked to ground with feedback. Jesus
Let`s focus there.
on your second board find the big coils and see where is shorted.
prepare your lab PSU and will lift it upLast edited by dj_ricoh; 09-21-2015, 04:49 PM.Just cook it! It's already broken.Comment
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Re: Acer M5-481PT backlight issue
Q16-3.3v on pins 2&3, nothing anywhere else. However only have 3v on one side of R296. Will steal from other board and report backwhat voltage you got on Q16?
that zone its super hot.
something missing there it does not trigger the BL.
check all resistor and diodes.
you even got a transistor hooked to ground with feedback. Jesus
Let`s focus there.
on your second board find the big coils and see where is shorted.
prepare your lab PSU and will lift it upComment
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Hello Team,
I'm back with another backlight issue that I thought was simple, but it turned out to be more complex than expected.
Let me provide a brief history: The TV was working well, then one day, the backlight started and shut down. I thought I had an LED issue leading to this behavior, so I replaced the LEDs with brand new ones. However, the issue remains the same.
Next, I replaced the electrolytic capacitors attached to the LED power supply, but the results were the same. I then replaced the driver, a OB3365RP, and did it twice due to the same result.... -
Hello, got an iPad Pro A2378 12.9 5th gen with no backlight. Got another test unit without screen, tested the screen, still no backlight with the test unit.
Figured out the backlight on the screen was bad, ordred a new backlight from mobilesentrix, *carefully replaced it* without damaging the lcd, oh well.
Final result, issue is still there, the screen has no back lights. So i'm back to square one, with 3 hours less and 100$ out, issue still on the screen.
The panel is still ok, i can see the apple in the middle of the screen when it kicks in, just no backlight.
Anyone... -
Hello team,
I'm back with another topic.
It's a 65C715 TCL tv with backlight issue.
But the problem is a bit strange.
When I took this tv from the marketplace backlight didn't work but picture was ok.
Back at home I checked with led tester if led are alive and I can find something different in term of voltage supply => nothing
Putting all back together the tv worked fine for weeks. => Contact issue??
Few moment later the tv has started to have backlight issue back, turning off and on worked sometimes and tv was working.... -
Hi everyone,
got an Acer Helios 500 Laptop (PH517-51) for diagnosing with a strange issue:
The laptop runs for a while (1-2 hours, sometimes less) and then suddenly shuts completely off, like someone pulled the power cord and restarts immediately after on its own.
If this happened once, then the laptop only runs for a few minutes until restart.
This happens regardless while staying in windows or uefi or in a linux environment.
At first I thought of a normal overheating issue, but as I monitored temps with HWInfo64, nothing seems very hot.
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Back Story
I just recently purchased a RZ09-01652 Razer Blade 14 Touch v4(2016) as a project. I suspect the original motherboard had overheated and caused board damage to the vrm's for the CPU and GPU as now that motherboard works however will lockup on you often due to hardware clock issues.
So after some research and looking at options for replacement motherboards I got a replacement RZ09-01952 razer blade 14 motherboard which has the 1060 vs the 970m that was in my original motherboard. I have contacted the seller about the motherboard being bad however I doubt they will be...
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