Hi folks,
I've been troubleshooting a new board I got. It's a 820-2327-A A1278 M97 with no power. So far I tracked down the problem to somewhere around R6911/R6912.
Pin number 1 on R6911 reads 16.5V however the other side (pin 2) reads nothing. SMC_BC_ACOK_RC is at 3.3V. I can't figure how that voltage disappears....
yakideo
Member
Last Activity: 12-13-2015, 07:01 AM
Joined: 02-12-2013
Location: Near the water
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Re: maxim 8731ae EQUIVALENT urgent please
I don't think there is any equivalent. It's a very specific IC. I you can't find it anyway try eBay.... -
Re: macbook pro A1278 - green light on magsafe - no power
The component that is missing on your board is R6995. It's part of a voltage divider for the 3GHot supply. Missing that one might very well not enable the power rail for the SMC. (see [url]https://www.badcaps.net/forum/showthread.php?t=42038[/url] for schematic/boardview)Re: macbook pro A1278 - green light ...not enable the...Leave a comment:
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Re: Apple Mac pro 13" A1502 820- 3476-A no power, need schematic and boardview
The one you linked is also only J44 MLB-4GB. The schematic doesn't specifically reference 820-3436, so I would assume it's valid for several boards....Leave a comment:
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Re: Dell n5010 can be converted from graphic version to non graphic
Download Google translate or similar to your phone and let it translate by using the camera.Leave a comment:
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Re: Macbook Air A1406 WLED Driver
LED displays are pretty sturdy as opposed to CCFL screens with inverters. Most of the time when the backlight goes bad it's a problem with the logic board/motherboard. You could try to replace the WLED driver but unless you know that all the components around are fine you risk blowing that one also. Best to take some measurements before swapping.
The values can be retrieved from the schematic however they might differ when tested in circuit. Hopefully someone else might have the same board and kind enough to do some probing. Your best...Leave a comment:
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Re: macbook pro A1278 - green light on magsafe - no power
What's the logic board code?Leave a comment:
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Re: Apple Mac pro 13" A1502 820- 3476-A no power, need schematic and boardview
Here are the board view and schematic. Good luck with your repair....Last edited by yakideo; 08-25-2015, 01:04 PM.Leave a comment:
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Re: Macbook A1278 M97 LCD backlight problem
I think I blew the 1-wire over voltage protection so I will have to repair that first. Still waiting on better tools I bought.
The fuse wasn't for the backlight wasn't blown. How do you mean when you say I should enable PPBUS_SW_LCDBKLT_PWR? Do you mean I should pull that pin high?Leave a comment:
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Re: Free wifi solution.
You need two SSID's on two separate VLAN's. The public VLAN should only have access to Internet. You will need a access point that let's you setup a captive portal. Additionally you would want to turn on AP isolation, so that clients connected won't be able to talk to each other directly.
Setting this up incorrectly can create a big security hole. Also as someone already mentioned collecting personal information might be touchy depending on local law.Leave a comment:
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Macbook A1278 M97 LCD backlight problem
Hi,
I recently bought a used Macbook Late 2008 Aluminum, A1278 M97 MB467LL/A with a non functioning backlight.
Currently I traced the problem to the Q9806 mosfet, I get 12.6V at the source however the drain doesn't seem to want to open. I check the functionality of the mosfet with a multimeter and it's looks good.
Looking at the schematic I can see that the Q9807 mosfet is supposed to drive the Q9806's gate low however the Q9807 is missing from the motherboard. It looks like it never was fitted on the motherboard in the first place but I could be... -
Re: DV6-2003eo random power off
Can an capacitor that measures 8.9 ohm be considered shorted?...Leave a comment:
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Re: DV6-2003eo random power off
I doubt that a reflow will help since I do get picture and the computer stays on (once it decides not to turn off before POST) enough time to do a video/cpu benchmark. Plus, this is a newer dv6 model, hopefully not suffering from the previous BGA defects.
Pictures of what? The entire motherboard?...Leave a comment:
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Re: Already Replaced Cap- Blown again
Just to clarify to why you need to use low ESR capacitors. Using low ESR capacitors prevents for example LDOs to oscillate, generating more heat and in turn damage that caps due to high temperature....Leave a comment:
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DV6-2003eo random power off
Hi,
I'm happy to be new here. I have a HP DV6-2003eo laptop that has some kind of intermittent power failure. Most of the time the computer starts (fan on, LEDs on) and then shutdown after a couple of seconds and sometimes it starts just fine to later shutdown and again fail to power on.
The same thing happens when running from DC-power, battery or dock.
I've have monitored the CPU/GPU temp to make sure that I'm not tripping any thermal shutdown. eg. temperatures looks good.
I have checked most of the N-channel mosfets and electrolytic...Last edited by yakideo; 02-12-2013, 04:35 PM.
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