Re: Gateway LP2407 Power Board dead
Selldoor, you are right, that cap is in backwards. I was aware they have polarity, but I mistakenly put it in backwards. Thanks for that catch.
bryanchan
Member
Last Activity: 08-20-2022, 04:40 PM
Joined: 01-27-2015
Location: Texas
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Re: Gateway LP2407 Power Board dead
I just noticed a discolored spot, the resistor has a brown/black/brown stripe which should be a 100 ohm resistor and it measures as such. Would this be indicative of any known problems? Should i just replace all the rest of the caps or is this something bigger than just a capacitor problem?
I also noticed on the inverter(?) board that the two caps on there are leaking as well. I know this shouldn't effect standby power with the power board disconnected. Just thought that'd be something good to know.
Thanks again...Leave a comment:
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Re: Gateway LP2407 Power Board dead
Oh, I should have mentioned that too. The board has been disconnected for all of these tests/measurements.Leave a comment:
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Re: Gateway LP2407 Power Board dead
In circuit, it measures .3 Ohms.Leave a comment:
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Re: Gateway LP2407 Power Board dead
I measured from Gnd to VDD and it measured 15.98VDC. From the SG6902 datasheet minimum is 15V and typical is 16, so I'm well within the requirements. Are y'all suggesting that the PFC chip is bad?Leave a comment:
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Re: Gateway LP2407 Power Board dead
I based that on the flux residue on the backside of the board. Maybe this pic will be more in focus. I had the aperture set too low....Leave a comment:
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Re: Gateway LP2407 Power Board dead
Yes, all of them show 0VDC. So, since I'm getting only 159V at the main filter cap, I have something wrong upstream of that, I would presume? I'm heading out to dinner, so I won't be back to reply for a couple hours.Leave a comment:
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Re: Gateway LP2407 Power Board dead
Okay, so this is what I've got.
Red to Green: .5 ohms
Green to Blue: 2.3M
Blue to Purple: Open
Purple to Red: Open
That should confirm that the transformer is dead, right? If so, does anyone know where I can get a replacement?
It has this written on the side.
CHK-078
DN 0639 A
Thanks in advance again....Leave a comment:
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Re: Gateway LP2407 Power Board dead
Now that I look at it, T851, the transformer in the top left of the board (component side pic) looks to have an open secondary winding. Is this typical?Leave a comment:
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Re: Gateway LP2407 Power Board dead
By the way, I do get 159V at the points across C854.Leave a comment:
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Gateway LP2407 Power Board dead
Hi Guys,
I went dumpster diving yesterday and came home with two large LCD monitors, one of which was the LP2407. I pulled the power board and found a bunch of caps bulging so I went ahead and replaced them. After plugging it in, I still got nothing. I looked in some other threads and based on the info there, have come to determine that there's no voltage coming out of the board at JP4. Everything pin shows no voltage. I checked the fuse and it seems fine. I was wondering where I should start looking.
It looks like someone has already replace R874 and R872. I have replaced...
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