Hi i was given a PC which supposedly had bad mobo but turned out its the PSU. its HP-D3057F3H PSU and it wont turn on when connected to mobo but turns on when i short the green and black wire. then i saw the 5vsb is only 2v when connected to mobo and 5v when not connected. could this just be a bad cap in PSU? when i opened it up there was swollen cap its a 10v 2200uf Ltec but i dont know if that for the 5vsb
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Last edited by nubinator; 01-15-2012, 10:22 PM. -
Re: HP-D3057F3H low 5vsb
I wouldn't usually expect a cap that big on the 5VSB but I suppose it is possible. A bad cap could definitely cause the rail to go low like that, I've seen it multiple times. There is the possibility that other caps are bad besides the one that is swollen, caps don't always show visible signs of failure. If you do repair it I would recommend replacing all the caps from questionable brands (in that PSU probably every cap or almost every cap, since HiPro tends to use lower end caps). That being said since it is a 300w HiPro and is standard ATX you may just want to replace the PSU unless you want a hobby project since it is only a mediocre brand and a suitable replacement can be had for less than $35.Last edited by dmill89; 01-15-2012, 10:54 PM. -
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Re: HP-D3057F3H low 5vsb
well got out esr meter i never use and it picked a couple of teapo caps 1000uf 6.3v and 1000uf 10v as bad also so will replace them see how it goes.Comment
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Re: HP-D3057F3H low 5vsb
1000uf caps are extremely common on the 5vsb rail so it is likely one of those is the culprit. As retiredcaps stated a 2200uf is used on the 5vsb in some designs, however such a large cap on a 2-3 amp rail is not very common. Although if the cap is visibly failed it still needs replaced regardless of what rail it is on since it will only lead to problems later.Comment
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Re: HP-D3057F3H low 5vsb
It could still be something wrong with the motherboard, loading down the 5vSB so much that it ends up at 2v, unless you already tried a new PSU and found the board to work."Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
-David VanHornComment
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My Hipro HP-D3057F3H only had 2.6V on the 5VSB
The fault was due to 5ohm ESR on one of the non-bulged Teapo SC 1000uf output caps; so i guess that the Viper22A detects overcurrent, and goes into a low power mode
BTW, this PSU has a tricky (for me), unusual, feedback circuitry on the 5VSB: The Viper22A is connected to the first optocoupler, of which the secondary side is earthed, and which is turned off or on by one of the TL431 shunt regulators (there's three on the secondary side of this PCB), which is connected to the adjacent optocoupler.
Also, in terms of being able to remove the board from the case, this is a technician-friendly PSULast edited by socketa; 07-30-2024, 04:48 PM.Comment
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Hello everybody,
i want to start with saying that i'm pretty new to all of this (both the hardware and the software) and only did this with 2 desktops.
My laptop is a T470 TYPE 20JN-S00U0L, i wanted to unlock the advanced menu just for the fun of it so i started by carefully disassembling the bottom cover, disconnecting the internal battery, locating the bios chip MX25L12873F on U49 and attaching the clip on it.
i connected the green ch341 set at 3.3v to the pc and tried to read it using ASProgrammer.
To be sure i read the chip 2-3 times and checked the bin files with ImHex... -
Machine came in as not powering on. Been to Apple who quoted a replacement board of course. So first thing was disconnect battery and plug in USB-C and it powers on fine. Plugged it all back in and boots to the OS just fine. It had a real old version of Monterey on it but looked pretty normal, so was scratching my head until I shut it down.
So what I found is that when this unit shuts down, it refuses to power back on via power button or lid open. PPBUS_AON and PP3V3_AON all stable, but just won't power on. When you plug in USB-C or MAGSAFE, PPBUS_AON is stable however PP3V3_AON now... -
Hello everyone! I'm trying to diagnose a fault. I don't have much experience, so I would appreciate any help.
Symptoms:
It stopped charging, drained the battery completely, and shut down. When powered from the adapter, it shows the battery symbol with a lightning bolt and then turns off. Without the adapter — completely dead. The charging indicator does not light up. Once I managed to start it using shift+opt+cmd+power for 5 seconds, then only power for 5 seconds, and then a short press on power. (I assume this was some kind of SMC bypass, found it somewhere on the internet).... -
What are the current favorite and available caps, maybe even polys, to replace 820uF 6.3V 8x11.5mm electrolytics?
The Asus P5G41T-M LX motherboard is similar to the one in the photo.
I've noticed 2 bulgy caps, one close above the north bridge, one below the south bridge.
Like most of the other caps on the mobo they are:
TK ATWY
820uF 6.3V
36 mOhm ESR
1140 mA ripple
Symptoms:
The mobo's gone downhill fast. It got stuck or rebooted maybe a handful of times over a few weeks or months.
Then one day multiple BSODs and... -
Hi,
Finally replaced all of the shorted 4148's and resistors and an blown tl431 on my FSP300-60GTF after 5VSB going crazy and destroying it self. Those components also made the secondary transistors appear shorted (while in reality they weren't).
Powered it on through my dim bulb tester and they (bulbs) only flash once meaning primary caps are getting charged, but that's it. No 5VSB, PS_ON voltages.
I am sure I have replaced the components correctly and that there weren't any shorted/blown traces left.
Any ideas where to go next?
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