Re: Dell Inspiron 15 - VGA_CORE voltage missing
Unfortunately no. I gave up eventually....
yohnsee
Semi-noob
Last Activity: 11-18-2023, 12:14 PM
Joined: 12-16-2017
Location: Békéscsaba
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Re: LG PSU EAY40504401 (LGP32-08H) repair
In-circuit measurements can lead you in the wrong direction. Nevertheless, I am curious about the solution....Leave a comment:
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Re: LG PSU EAY40504401 (LGP32-08H) repair
Hello,
So if I get it right, you did not remove the PSU from the TV, and all the symptoms you have can be seen when you want to start the TV?
From what you described, I can only think of a capacitor problem.
Think about it: standby led flashing stronger-weaker-stronger-(then the TV should turn on). But in your case it only starts the blink sequence again. From this I would assume the PSU does not have the needed power reserves to start the display, MB and backlight at the same time. Either one of these...Leave a comment:
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Asus FX505GT motherboard troubleshooting
Hello,
I would like to ask for some help regarding the motherboard in the title.
My friend asked me, if it is possible, save it from the dumpster.
His story: during regular fan cleaning, he saw some smoke emerging from the motherboard, near the RAM section. He says there was no obvious reason for that (no screw fell into the board, etc.).
Facts:
-board does not power on
-applying 20V from current limited power supply, all VSUS (standby) voltages are present, except one: 1.05VSUS, page 48 in PDF
-removing JP8201 and JP8203 1.05V is present on U8200... -
Re: 715G3812-P02-H20-003D Philips TV power supply
Dear friend,
I think I was able to make the TV work, mine had mainboard problem. The PSU was fine, I didn't have the experience back then, and searched the problem where it didn't exist.
Back to your panel. TNY277PN is easy to order, I don't know what other codes you have, but the only thing to look out for is the package. I mean, I don't remember if it is an SO-8 SMD package or DIP-8. If these two factors are met, the other codes are not important on the chip, as they mark things like "green product"...Leave a comment:
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Re: Samsung UE50EH5300 - bad picture, helping to diagnose for a friend
If you want to put more time into it, go ahead. But this is definitely a screen issue. As it has very little to do with heating up (the expanding tracks still have the right contact inbetween the LCD layers) it is a false hope. My best bet would be to identify the MB, Tcon, backlight, PSU and put them on ebay, to get a few bucks back, maybe make a little profit. This TV doesn't worth the time....Leave a comment:
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Re: Samsung UE50EH5300 - bad picture, helping to diagnose for a friend
Sorry to break it down this way, but TCON will never make horizontal problems. As far as my knowledge goes, tcon only can be suspect in such cases where there is a pattern in vertical disfunction....Leave a comment:
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Epson EB-W8D shuts off - software failure?
Dear forum members,
I came here for a little help repairing my projector.
Symptoms: when I turn it on, it starts normally, then the attached picture greets me (sorry, didn't have white background). If I press no buttons, the machine can stay in this state as long as needed.
But, as soon as I press the source button, it searches trough the inputs, and switches on the input that is connected. It displays the picture nice and flawless, but from here, none of the buttons work. And from this point, in usually 3 minutes (+/- 10 seconds) it switches off, and all the 3 leds... -
Re: Dell MK463 N750P-00
Okey, now the history of the machine is also clear for me.
To make progress in this post about the PSU, I would suggest NOT to tamper with it. If it works fine, don't repair it. But if those caps, and their bulges bother you, replace them. Go ahead, desolder them, order new ones with the same capacity and voltage rating, and with the same physical attributes (diameter, height, pin distance). This should do the trick, and after that you can call it a day for this post, and we can move onto the other, to find the problem on the mobo.Leave a comment:
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Re: Dell MK463 N750P-00
Hello,
I read the linked post above, and have a few thing that need clarification.
So you started with a computer that does not want to start and beeped.
From here, you put an old VGA card in, and the computer said, there is an error with the PCI-E lane. Then you replaced the capacitors, and moved on to the PSU? This part is not really clear for me, what is the problem with the PSU, when the computer POSTs with it? Or is it working with an other PSU?
To your original post: first check for obvious problems, like are all the pins...Leave a comment:
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Re: Power-one FNP1500-48G repair
Yes, I only disconnected them for the photos.
One more interesting fact: I connected an external 48V power supply on the secondary side, and when I tried to power up the faulty PSU, it wanted to turn the fans, but only for a fraction of a second.Leave a comment:
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Re: Power-one FNP1500-48G repair
Dear CapLeaker,
thank you for the reply. I am aware, that the secondary side won't start, until the PFC boosts the main rectified voltage. I have measured every diode, resistor and capacitor around the PFC controllers, compared both sides, but so far nothing seems off.
I only attached the photos to give you a picture, how the layout looks like. If anything helps, by taking better photos of a part, I will gladly do it.Leave a comment:
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Power-one FNP1500-48G repair
Dear forum members,
I came here for some help with repairing this PSU.
I have attached every pdf I could find for it. I even contacted ABB (this company bought Power-one back then) and asked for schematics, but they didn't even answer.
This nice PSU came to me with short on the mains filter capacitors (2 of them were leaking the electrolyte, and caused a short) and it even blew the inrush current limiters. I attach a few photos, so far I have done the following:
-desoldered all main capacitors, cleaned the mess and digged down to the inner layers to see, if there is... -
Re: Sharp LC-42SB45U Powers on at Random Intervals after Cap replacement
Hello,
the turquoise components are also capacitors. This question leads me to ask you, have you checked your work, I mean, haven't you soldered any caps backwards? Every new cap has the uF value the same as the old one? Are there any shorts where you soldered? No offense, just asking.
Second, you should check the voltages when the set is in standby mode (or should be), and when powered on. Good start would be with CN902. Report back the voltages, then we can move on.Leave a comment:
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Re: LG PSU EAY40504401 (LGP32-08H) repair
Hello and welcome to the forum!
First of all, as I see you have a lot to learn about electronics, but don't worry, no one was born with this knowledge. And second, you came to the right place, on badcaps every member is willing to help (so far I have noticed).
R_J told you how you can test the zener breakdown, but if you are more a visual type, watch this: [URL="https://www.youtube.com/watch?v=8G6rGZDiEBM"]Zener testing.[/URL]
First when I test a bad behaving circuit, I try to break...Leave a comment:
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Re: Panasonic TNP8EP101 - no standby
Update on the case (also, good news everyone)!
I found the bad part. The little bastard (disguised as D825) was measured 30K Ohms in one direction, 68K Ohms in the other direction. As I changed nearly every single diode and resistor in the standby part, I also removed D826 (better be safe than sorry) and soldered a good-looking 1A schottky there.
And now I have standby (5.7V). Thank you again R_J, you helped a lot (again).
After these seemingly hard repairs I feel a little pride, that I could also do this.
...Leave a comment:
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Re: Panasonic TNP8EP101 - no standby
No, I have nothing, not even a tenth of a volt. I used my oscilloscope to see if my multimeter is too slow for this measurement....Leave a comment:
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Re: Panasonic TNP8EP101 - no standby
I tested every component you mentioned above twice, also by soldering them out and measuring out-of-circuit. Everything is OK, and I am starting to pull my hair out. Normally it is not a big deal to repair a SMPS with schematic, but this time it is....Leave a comment:
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Re: Panasonic TNP8EP101 - no standby
Hello R_J, and thank you for your comment.
These were the parts I first tested, but now I tested them again. Nothing is bad, shorted, even the cap has its nominal value.
I soldered a DIP8 socket on the board, so I can quickly change the IC. I even plugged the board in line voltage without this IC. And it confirmed your theory, without this IC there is absolutely no voltage present on the VCC line. I wonder why it climbs up to 9.5V only?...Leave a comment:
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Panasonic TNP8EP101 - no standby
Hello everyone,
a long time ago I replaced the PSU of a TX-L42 series LCD Tv. Now I have the bad PSU and I want to repair it, but have no luck so far.
I attach the schematic and the part where only the power supply unit is visible.
I have spent many hours figuring out, why mine won't start, but so far I have no answer. All the time I was looking at IC803 (A6259H) and its surroundings, but found no faulty component. Only thing I can't test is the transformer (T802) but I don't think it is faulty. I have ordered 2 replacement ICs for IC803, but when I wanted to start...
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