Re: Seasonic X 850W not turning on
Yes, sorry, I must have moved the file in another directory so it broke the link.
Here it is a new one: [url]https://mega.nz/#!1RxkxY4L!LkH33C09s5GeCj0ezWT2CwMJyoGWvZBuAUOThSOIMxs[/url]Re: Seasonic X 850W not turning on<b...ThSOIMxs[/url]...
MichR
Member
Last Activity: 04-23-2022, 02:43 AM
Joined: 01-10-2016
Location: Italy
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Enermax Revolution87+ 850W high pitched noise
Here we go again with another PSU!
Because of the last two successful repairs a friend of mine brought his Enermax Revolution87+ 850W power supply. He complains that his PSU emits an annoying whining when using the PC in idle.
Actually it's true, it's really annoying and disappears on higher loads (for instance when running a game). On idle, this whine is louder whenever I do something (e.g. move the cursor or a graphic element, such as the scroll bar on a web page). I assume that, since output voltages are constant, the whine is definetely caused by a change of current (supplied... -
Re: XFX XTR 650W power on issue
Thank you, momaka.
So I decided to test my 'solution', which basically decreases the 'on' threshold voltage Vth(on) to be a little lower than the minimum Vbus voltage (which I have when the current generator inside the ICE chip is connected).
Requesting Vbus[min]>Vth(on) gives a numerical solution of R501 <(about) 120k.
I therefore placed a 100k resistor in place of the original 120k of R501. This, assuming 357.8V on the primary cap, gives the following theoritical voltages:
Vbus[max] = 6.983V
Vbus[min]...Leave a comment:
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Re: XFX XTR 650W power on issue
Ok, I redrew the schematics used by the PSU to provide +12V to the output.
The more complete schematic is available in the attachment.
After some measurements, I finally found out the cause of this problem. Apparently, when the issue shows up, the pin "VINS" of [URL="https://www.infineon.com/dgdl/Infineon-ICE2HS01G-DS-v02_01-en.pdf?fileId=db3a30432a40a650012a458289712b4c"]ICE2HS01G[/URL] is at 1.21V instead of 1.48V when the PSU has turned on. According to the datasheet, this IC requires a VINS voltage greater...Leave a comment:
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Re: XFX XTR 650W power on issue
So I carefully measured and monitored all the pins of the monitor IC, a [URL="http://www.siti.com.tw/product/spec/Power/PS223.pdf"]PS223[/URL]. Here are the results:[LIST=1][*]PGI: goes to around 2V when I power on the PSU using the flip switch trick. It's 0V if the unit is off or I press the power button on the PC.[*]GND: always 0V.[*]FPO: it's 0V at first. When I power on the PSU using the flip switch trick it stays at 0V. When it's off it goes to 5V.[*]PSON/: it's 0V at first, but when the PSU has been shut down, it goes to 3.5V with...Leave a comment:
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Re: XFX XTR 650W power on issue
It's been a week since I've reassembled the unit. I connected it to my PC, but kept it [B]outside[/B] the chassis. During all this time it didn't give me any issues.
So today I decided to put it back [B]inside[/B] the chassis and the described issue showed up at its first use. Strangely enough, when I removed it again and reconnected from the outside, the issue persisted. So one of these causes must have "triggered" this behavior:[LIST=1][*]Grounding: I thought the physical contact between the PC and PSU chassis could have been the...Leave a comment:
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Re: Yoga 700 11ISK multiple shorts
Here I am some months later. I finally bought a new Yoga 3 motherboard and replaced the old shorted one. I must tell you that:
- [B]a Yoga 3 sensor board must be bought[/B], otherwise the screen won't automatically rotate nor dim. This is mainly caused by the different accelerometer chip used in these two computers.
- the measured capacity of the battery is exactly the same specified in Yoga 3 battery, regardless of the extra available capacity of Yoga 700 battery.
Another issue is caused by WLAN whitelisting...Leave a comment:
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Re: XFX XTR 650W power on issue
Thank you for linking that video, it was of a great help.
Coming back to the topic, I was finally able to see the waveforms of the outputs. I did not even bothered to measure the ripple, since it was very low (<50mV) and no overshoots could be seen on startup/shutdown of the power supply.
It must be said that the issue is not showing on my testing setup. If no one has any suggestion, I think I will reassemble the unit, (externally) connect it to my PC and monitor the outputs before and after the issue.Leave a comment:
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Re: XFX XTR 650W power on issue
Yes, I was using the ground lead provided with the probe. As suggested from the video, by using a much shorter and more direct ground path I was able to remove much of this unwanted e.m. "noise".
I also noticed that this "noise" is generated by the power supply. Indeed, when I shut it off the "noise" vanishes completely.Leave a comment:
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XFX XTR 650W power on issue
Hello guys,
I've had this XFX power supply for a long time, and recently it started behaving like one of [URL="https://www.badcaps.net/forum/showthread.php?t=49995"]these Seasonic X units[/URL].
TL;DR: I have to flip the on/off switch multiple times in order to startup the power supply (once it starts, it works great). I need to do this when I shut down or put in standby the PC.
From the previously linked thread, I found this helpful advice:
Therefore I decided to take apart the unit and investigate on the issue.
You can find [URL="https://www.techpowerup.com/reviews/XFX/XTR650/4.html"]HQ...Last edited by MichR; 08-18-2018, 12:31 AM. -
Re: Yoga 700 11ISK multiple shorts
Alright.
A last thought for whoever stumbles across this thread: Yoga 3 motherboard (LA-B921P) should be compatible with Yoga 700. Form factors look the same and connectors are disposed in the same positions ([URL=http://blog.scarletdevil.info/blog/wp-content/uploads/2018/02/664d4926ac120efa7de3dcaf26145b2b.png]Yoga 700[/URL] - [URL="https://www.notebookcheck.net/fileadmin/Notebooks/Lenovo/Yoga_3_11_80J8001WGE/Len_Yoga3_11_52.jpg"]Yoga 3[/URL]). Also, lower and upper cases, as well as all the daughter...Leave a comment:
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Re: Yoga 700 11ISK multiple shorts
Thanks. A new CPU costs about 60USD, but I don't have the tools to replace it. I thought a reflow could have helped if the shorts are among BGA balls, but I cannot be sure. The only option left is to buy a new motherboard, which costs more than 150USD. In my opinion it's way too much for such a board.
I think I'll have to sell the whole laptop as is....Leave a comment:
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Re: Yoga 700 11ISK multiple shorts
That's a pity. Is there anything I could do? May a reflow be of any help?Leave a comment:
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Re: Yoga 700 11ISK multiple shorts
No shorts on +5V, but I checked anyway - nothing. However, I found pins 1 and 4 of D45 are shorted to ground, so I decided to desolder it. Differently than Yoga 3, these are connected to a pair of differential lines, much probably U2DN1, U2DP1 (USB 2.0 pair) if I follow Yoga 3 schematics.
I believe this is sufficient to state that CPU is the issue here. What do you think?Leave a comment:
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Re: Yoga 700 11ISK multiple shorts
Thank you for your prompt response.
I know this is secondary but it was the first thing I noticed when i disassembled the laptop. However, I am still focused on finding the shorts.
I searched online some information about the ICs on the board, looking for one that may be the culprit. I could not find anything related. However, I found the schematics (attached below) of another Lenovo notebook that uses the same audio codec (Realtek ALC3240). According to it, the IC is powered by +3VALW and +1.8VS (the Yoga 3 schematics had...Leave a comment:
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Yoga 700 11ISK multiple shorts
I've got this Yoga laptop for a reasonable price. Seller said it suddenly turned off. However, he or someone else tried to repair it, making the situation even worse: he told me the NPCE388 has been replaced, but nothing else was done.
Actually, some power supply jumpers have been desoldered. Sadly, all of these rails are shorted to ground.
Before going on, take a look at the motherboard. This is the best quality picture I could find of it:
And this is a particular of my board:
I could not find any schematics of this board over the web.... -
Re: Seasonic X 850W not turning on
As previously said, here you can find my partial schematics of the unit:
[url]https://mega.nz/#!JJoyFK5L!LkH33C09s5GeCj0ezWT2CwMJyoGWvZBuAUOThSOIMxs[/url]
JPEGs are also attached here. If you download the entire archive you will find a .PSD (photoshop) file with the monitor board diagram whose routes can be hidden at will. First layer can be deleted (it's only there to reduce file size of about 10MB).
Note: in the PFC partial schematic, labels like MONITOR[X] mean that the branch is connected to the number X pin...Last edited by MichR; 05-28-2018, 10:37 AM.Leave a comment:
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Re: Seasonic X 850W not turning on
This reminds me of the study of an RC network. When R approaches 0 and a step voltage generator is used, the current tends towards a pulse which lasts longer the larger the capacitance.
I haven't studied it yet, but the ohm meter should work like a (step) voltage generator applied to the unknown resistor. The current is then measured and the resistor is then calculated with the Ohm's law.
I could not believe it was so simple! I connected the power supply to an old motherboard and it worked!...Leave a comment:
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Re: Seasonic X 850W not turning on
Update:
Some folks over eevblog helped me out identifying a bad MOSFET I found on my power supply. For anyone's interested, here's the picture of it:
its reference designator is "U4" and its marking is "5014T". Apparently it's a SPN5001 (a 600V VDS N-channel MOSFET). More info [URL="http://www.eevblog.com/forum/beginners/ic-identification-107168/"]here[/URL].
I replaced the two on my board with an equivalent BSS127.
Now +5VSB is super stable, but it doesn't end here....Leave a comment:
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Re: Seasonic X 850W not turning on
Sorry for this stupid thing I said
. They are indeed connected to +12V, and the fault it's probably there, since the sympton revealed with DMM seems to be a MOSFET that I charge/discharge when I invert the polarity of DMM's clips.
However I don't know if this behaviour is normal or not. I just can't access to the vertical board to see how these transistors are connected....Leave a comment:
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