I have one of those va912b's with a bad power supply. I replaced 3 of the caps that were bulging, and when I plugged it pack in, I heard a pop (not an exploding cap) and nothing happened. Did I fry it with a bad joint or something? Or should I just replace the other caps too (except the big one).
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Re: Replaced bulging caps, and pop... nothing
Now with pics of my masterless work. I circled the new caps, and the only joint that rally concerns me is the bottom one with the slight scorching around it (that was there before I got to it). I struggled with that joint.Attached Files -
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Re: Replaced bulging caps, and pop... nothing
Show us a picture of the switchers and the diodes. Those are the other things that tend to go "pop". Also a complete pic of the underside of the board would help too, as there are a lot of SMD components on that side.Comment
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Re: Replaced bulging caps, and pop... nothing
Ya, I agree with replacing the others as well. Usually when they are in a cluster like that, they all get affected. You could take off the other ones and test them with a meter if you have one. Also check the bottoms of them for bulging, for some reason some brands tend to go bottom first then bulge at the top if it's that bad.Comment
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Re: Replaced bulging caps, and pop... nothing
I'd expect that area of a power supply to use low ESR caps. I am not familiar with the "NTE" capacitors you used as replacements. What are their specs and how do they compare to the originals? They're not a brand I've heard of before, so I'm unsure of their long term reliability.Comment
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Re: Replaced bulging caps, and pop... nothing
If you have no power and no power LED, then check the bridge rectifier (BD101) for shorts. Number the pins 1-4 and put your multimeter on 200 ohms.
With power off and lcd unplugged, measure pins 1-2, 1-3, 1-4, 2-3, 2-4, 3-4. Any reading under 30ohms suggests that the bridge rectifier may be shorted.--- begin sig file ---
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Re: Replaced bulging caps, and pop... nothing
They are higher voltage with the same uF as the originals. I don't know the other specs, and haven't used them before either. They were available at the local electronics parts store, and they use them for repairing LCD's...
You are correct, no power, no LED. I'll check that this weekend. Thanks.Comment
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Re: Replaced bulging caps, and pop... nothing
Also check this fuse, the live wire goes through this fuse before anything else.
Its probably blown, but without finding out the cause, it will probably blow again.
mastertheknife.Attached FilesLast edited by mastertheknife; 01-28-2011, 11:07 AM.Comment
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Re: Replaced bulging caps, and pop... nothing
That switcher MOSFET looks a bit fishy to me. If you can get a close look at it, check for any pitting, cracks or discoloration. Also check the fuses (anything labeled with an "f" on the PCB) for continuity. An open fuse will indicate that it is more likely a silicon failure than a capacitor failure.Comment
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Re: Replaced bulging caps, and pop... nothing
Having worked with all sorts of electronics over many years...have never heard the term 'switcher' before.Terminology for many subjects can have different names for different things...so define 'switcher' in English please ???Comment
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Re: Replaced bulging caps, and pop... nothing
Thanks,I know what Mosfets etc are, as I am electronics qualified,but you are the only one I have ever seen use the term on here,or anywhere else. You learn every day ....ehComment
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Re: Replaced bulging caps, and pop... nothing
The fuse is definitely blown. But I don't know about what I'm assuming is the switching transistor you're talking about. It's definitely funny looking, but I don't know what it's supposed to look like. I can't read it either, so I don't what to replace it with.Attached FilesComment
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Re: Replaced bulging caps, and pop... nothing
looks more like it has blown apart
your only chance would be to find the missing chunk with the part number on it..
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Re: Replaced bulging caps, and pop... nothing
Data Sheet for the part is as follows:-
http://pdf1.alldatasheet.com/datashe...FSDM0565R.htmlComment
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Re: Replaced bulging caps, and pop... nothing
https://www.badcaps.net/forum/showth...highlight=acer
looks like this acer uses the same p/s
wonder if samson still has to help identify parts?
Don't miss Rtechs post aboveWhatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!
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Re: Replaced bulging caps, and pop... nothing
Used by some Acers,some Viewsonics and Hanns G HX191.....plus no doubt many others.Comment
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Normally, I never post repairs this quick after I do them, because… I am usually very slow.
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I picked it up last November from someone on my local Craigslist. It wasn’t very close to where I live, but was close to a family friend that I had to go visit anyways. So after watching the posting on Craigslist for a few weeks and seeing it getting...
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Hey guys, bit stumped with this laptop after replacing 2 blown components i.e., MP86493, MP2979A.
To begin with, this laptop was dead-dead.
Now with replaced (visibly) blown components, i do get some progress; after connecting battery or main cable;- am getting white power led
- 5-long-flashes on CAPS Lock and NUM lock
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Hi folks,
I'm new to this forum. So my trusty 17-year-old LG 47" LCD recently died. As I was booting it up, I heard a hum followed by a loud bang, sounds of pieces flying around, and loss of power to the unit. Inspecting the PSU, I saw two obvious problems: a blown thermistor (bang + flung pieces) and a visibly bulging main cap. Inspecting as many components as I could with my Fluke MM, I diagnosed that the following components on the "hot side" of the board were also bad: one of the 2 main MOSFETs, main 8A fuse, small cap (25V 47uF) connected to main caps, and a blown... -
LG 42LB5D (42LB5DF-UL) from 2008-01, unit is in good shape and no obvious heat damage or cracked solder on the boards.
Problem:
On first power-up the power LED flashes green about 18x and then stays solid. No backlight or image is present. Click power button, wait 10s for a click and the LED turns red. Wait 1-2s and hit power again and maybe it'll power up fully after 6 green flashes. If it doesn't light up on the sixth flash then the cycle repeats.
It seems that if the mainboard power is left on for a few minutes (solid green power, no backlight, no image)... -
Hello,
First, I am a complete noob with high voltage stuff. I'm learning, but I need help by someone looking over my shoulder.
I recently came into posession of a Heathkit IO-4205 5MHz Dual Trace Oscilloscope. The documentation is copyright 1978. I'm told it works.
I opened it up to check the caps before I applied power, and found the following black caps and wanted to know what they were. They are on the power supply board. I was able to read the name and model and came up with, "Nytronics 162J-1, 0.1uF, 20% tolerance, 2000VDC."
...
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