Display backlight capacitor intermittent

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MacBook Unibody A1278

13" aluminum unibody, 2.0 or 2.4 GHz Core 2 Duo processor.

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Ken @mactechplus

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发帖于: 2017年6月21日

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Display backlight capacitor intermittent

I'm Trying to fix a Unibody MacBook, late 2008 ,13 inch , 2ghz. The backlight goes out on the display when it warms up. Backlight will come on briefly after power switch is pressed for a short bit. Works great on external monitor. Have replaced heat sync temp sensor, replaced entire screen with known good one. It acts like a capacitor issue. Do any of you know the location of the capacitor that triggers the backlight on this motherboard? And if so would you kindly share the info? Thank you for your help

@oldturkey03

@Stefano Gigante

@mayer

@danj

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I think you would need the full schematics and a multimeter to test everything. What happened before? Any damage?

由 Gigabit87898 完成的 2017年8月1日

@mactechplus is yours a 820-2327 logicboard?

由 oldturkey03 完成的 2017年8月1日

What makes you think is a capacitor issue from all of the backlight circuit components? When all of this started? Did you dropped the device? Liquid spill or out of nowhere? @mactechplus

由 Oros 完成的 2017年8月2日

@oldturkey03 Macbook NON-Pro 13" A1278 Late-2008 Logic Board C2D-2.0GHz 820-2327-A

由 mayer 完成的 2017年8月2日

@mactechplus contact me by email for the schematic and BV.

由 oldturkey03 完成的 2017年8月2日

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I think you would need the full schematics and a multimeter to test everything. What happened before? Any damage? — Gigabit87898
What makes you think is a capacitor issue from all of the backlight circuit components? When all of this started? Did you dropped the device? Liquid spill or out of nowhere? @mactechplus — Oros
@oldturkey03 Macbook NON-Pro 13" A1278 Late-2008 Logic Board C2D-2.0GHz 820-2327-A — mayer

Owiti Wycliffe @wycliffe254v6 声誉积分: 1 · Answer 1 · 2022-11-26T13:32:35-07:00

Owiti Wycliffe @wycliffe254v6

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发帖于: 2022年11月26日

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I think you are right. I have the same machine and it has the same problem. My case is a bit different. When my Mac first behaved that way? I followed up and found that my LVCD fuse blew and so I had to buy a new fuse. I did this twice and still the fuse kept on blowing and so I decided to short with a wire. this time round the display worked for some times and went off when the machine warms. I've been thinking the problem ever since and I think you are right. it can be a capacitor issue. let me try to see if I can find the capacitor itself

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@wycliffe254v6 - Not likely, more like you have a bad LVDS cable or the connectors either within the display or the main logic board have corrosion damage.

由 Dan 完成的 2022年11月26日

@danj - So does it mean that there is no capacitor associated with the led display lights? apart from the fuse, what else do you suspect can be the major problem.

and apart from the ground shorting, what else do you think can be causing this fuse to blow out

由 Owiti Wycliffe 完成的 2022年11月27日

@wycliffe254v6 - That’s not what I said… LED drivers use what we call a Buck Inverter circuit to alter the voltage for the backlight it uses both a cap and a coil.

But! Your issue is more likely a cable and/or connectors the cable connects to. I would say nine out of ten times that’s the issue as a short (burnt fuse) is the tell tale symptom of this.

由 Dan 完成的 2022年11月27日

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MacBook Unibody A1278

Display backlight capacitor intermittent

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