Hi to all, I have a B550M DS3H from MSI, it works ok, but when I turn off PSU, It loses the bios saved parameters, changed the 3V battery and measured Vbat line and its ok, 3.2V, so its not the battery. I have the diagram and boardview, updated the bios to latest version, and still no go. I uploaded the 3 files in case someone needs them.
I have traced the line Vbatt to the EC and the RTC and it keeps ok when I remove PSU power, it meassures 3.some volts.
Any ideas? thanks a lot...
foshland
Senior Member
Last Activity: 12-07-2025, 09:32 PM
Joined: 01-27-2017
Location: Ceuta
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MSI B550m DS3H Resets Bios parameters when I power off from PSU, coin Battery is OK
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Hi and thanks a lot for the guidance - help. I answer in red color, by now the pin A13 and A14 is low as I see, just 300mV, answer below.
About looking with microscope, I have looked a lot and found nothing with the visual - microscope inspection... -
Hi again, meassured all the voltages possible against the working board and they are the same, 0.8 (aprox), 5, 12, 1.2, 1.8 and all the meassured ones. I am now thinking its something related to EC (I have 2 EC chips and 2 EC bios) or SIO chips.
(As far as I know I have Resume reset at 1.8V in the nearest test point to the CPU and continuity with that point and the CPU pin connection)
Can someone give me a direction to what more to test?
Thanks a lotLeave a comment:
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Hi, no, I bought those 2 boards as broken, no more information of where they come from. The first board, the repaired one, had the 2 BIOS corrupted, just flashed them and the board is working perfect now. The second board, at first time, seemed to have the BIOS corruption too, but now im not sure, when the chips where connected in the board they where not readable, i had to desolder them, flashed and verify that they are ok, after that, I checked the no read from BIOS problem Im facing, I have tried the 4 bios chips in the working board and they work. The 4 chips in the non working board are not...Leave a comment:
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Tried earlier BIOS, nothing changed, I have no signal in any pin of the BIOS chips (measured with oscilloscope). I have checked all the resistors and componentes between bios chips and CPU socket, they are all OK.
I think the CPU is not triying to read from BIOS, maybe it is in some kind of sleep state or similar, hope someone knows something about what to check nowLeave a comment:
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Hi, I removed the 2 bios chip, and programmed the 4 of them (2 of every motherboard, with the last BIOS) and tested in the working board, they work ok, I know how the switches works and I´m using (in the non working board) in single bios mode, but it doesnt work in bios 1 nor bios 2.
I use the same CPU (Ryzen 5 2600) in the 2 boards, and the same memmory module and PSU.
The main problem I have is that I dont know if, when board is started, the BIOS chip is waiting for some data from the CPU or another part of the board, or if the BIOS, when powered up, will send data...Leave a comment:
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GA-AX370 Gaming K7 boardview
Hi to all, im looking for the boardview, all I have is the files atached, thanks a lot... -
GigaByte AX370 Gaming K7
Hi to all, i have 2 of those motherboard, same model, same revision, the first one had BIOS corruption and is now working, the other one had BIOS corruption and I programmed them, motherboard starts but I only get 00 error on the 2 digit display, I have all the voltages OK and have tried with the bios chip from the working one, with same result. I have revised the socket and all the pins holes seems OK, If I put the oscilloscope in the BIOS chip I get no communication, just a straight line.
What can I look now?
I want to know if the BIOS chip should send in the pin 2... -
Finally i discovered what the problem was, they are limiting resistors in the main section (120VAC), when the power supply works ok, it closes a relay and it bypass the resistors, the problem was that the relay had the coil open and the line was allways through the resistors.
Hope it helps someone...Leave a comment:
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SMPS 750W 25VAC out not working correctly
Hi, I have a power supply that now is working but generating a lot of heat (200ºC) in the resistors circled by green (see photos) with a minimal load (60W). Output voltage is correct with that minimal load. What cai I look now?
Thanks a lot -
Ok, I made a wrong assuption and yes, there is a smd NTC under the CPU, in the space inside the socket, so ill work in that direction.
As far as I could check, the resistor and the connection to the I/O chip is ok, have to check a pair more of details and will post if there is any good news.
Thanks a lotLeave a comment:
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MSI MAG Z390 Tomahawk BIOS temp, allways at 0ºC and CPU goes protection 800Mhz
Hi to all, my motherboard (bought second hand as faulty, but now working after cleaning the ram slots) have a strange failure that shows 0 Celsius degrees in BIOS, because of that, the CPU goes to protection mode and gets stuck at 800Mhz.
Since its a 8-9 Intel generation, I know the CPU temp is the hottest temp of the cores (as i have read in intels documentation) so its not a diode or sensor on the board.
External temperature (motherboard temp) is working OK, 27ºC more or less
In windows, all the software I have tested shows correct the Core temps
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Re: Lenovo Legion Y530 turns on but no display or external display
Hi, meassure again, in resistance mode, PL1801, it should be arround 80 ohmsLeave a comment:
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DELL XPS 9560 Burned zone need photo please
Hi to all, I have a XPS 9560 with some faults, im working on it for fun, I have a "burned" zone I need to dremel but afterwards ill need a photo of the zone for rebuilding as far as I can, I have the schematics and the boardview but will like a photo, if some of you can get any so I see the traces will be cool.
It was some kind of lucky that the zone had not too much components, so I think I can deal with it.
Its under the zone where PC308 PC309 and PC337 is located, next to PU300
Thanks a lot for all and "pray" for me
...
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Re: Gtx 1060 windforce oc 3g
Hi, look for the 1080 card, its the sameLeave a comment:
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Re: I need help with fixing my HDD(WD25000AAJS)
First, if you didnt yet, clean both pcb and then clean well the contacts on the J1 "connector" pads on both pcb, they look some dirty and maybe you think its not that serious, but i revived a pair of HDD cleaning those contacts, may worth a try. A pen eraser does it nicely, try to make them as shiny as possible.
Good luckLeave a comment:
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Re: Nintendo Switch drains battery in 2 days when off
Hi, not yet, it is sitting in the shelf for next week or so, ill post if I find something newLeave a comment:
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Re: Gigabyte Aorus 1080ti - card not initialising
preheat the card, its the best when working with graphic cardsLeave a comment:
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Re: GTX 1660 BIOS Beep Error
Does the own card has a buzzer? first time to hear about that. Or do you mean the beeps of the motherboard?Leave a comment:
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