So i got my replacement board and everything is working besides the screen (track) pad.. I tried all trouble shooting with drivers and BIOS but nothing helped. Voltages are present and the screen x software wants to calibrate it but stops with an error.
Any ideas?
dbuergi
Senior Member
Last Activity: Today, 01:53 PM
Joined: 07-24-2024
Location: NRW
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BMAX B5A Pro fast fan spin + power led but not starting
Hi all,
since i can exclude a bios fault i'm looking for a hardware problem on this one. I got this mini pc with no power and a blown up mosfet with damaged ground bad. I cleaned everything and drilled the area until the short was gone and i was able to rebuild everything.
When i plug in the power supply the power led turns directly on and i get the fan on full speed but nothing else. I can power the board off with the button.
The coils don't show any voltages and other measurements are marked on the picture.
There are no hotspot on the board and with voltage injection... -
BMAX B5A Pro G7R2 Bios
Hi all,
i got this Mini PC with a board damage and repaired it. When i plug in the power supply the unit starts directly but the fan is only giving a short twitch. Nothing else happens and i turn the PC off with the power button.
B5A Pro G7R2
SN 9450C251100394... -
Minisforum G7 PT 7945 direct power on, fast fan spin but no display
Hi all,
since i already flashed the bios chip without any success there must be something else wrong and i hope you can help me to solve this fault.
When i insert the power connector the PC starts and the CPU fan blasts at full speed. GPU is not doing anything.
I have all voltages present and no shorts.
When i press the power button the CPU reaches 90C in some seconds and the PC turns off / in standby. The PCU starts to make cheeping noise during this process. As mentioned i rewrote the bios chip, checked bios battery, made a reset and cleaned RAM contacts.
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Thank you but didn't work. Maybe it's more than a simple bios issue....Leave a comment:
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Minisforum G7 PT7945 Bios needed
Hi all,
when i start this machine i get LEDs and all voltages but only one fan spinning at full speed and no picture or any booting.
Bios reset didn't help.
If needed board number should be DRBAA V1.0
HD506VG7PTEDMPE00125... -
I removed several coils and mosfets but my voltage injection only showed GPU and GPU drawing 1v and 0,4a.
Since i already wrote the board off i removed the CPU and the coils went back to normal values but the short at the GPU stayed.
Never had a board where CPU and GPU died. So Case closed and i will try to get a replacement.Leave a comment:
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ACN to GND 4,3 Ohms and ACN to CPU coils 6,8 Ohms....Leave a comment:
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This board is giving me serious headache and i put it to the side for the next weeks.
Here are some more observations i made.
Mosfet 2 removed i get 20v through mosfet 1 and also gate shows 25,9v.
Voltage injection on source of mosfet 2 with 1v and 2a shows CPU heating up in the middle around 30C. On other coils i'm able to heat up GPU in the same way. No extraordinary heatspots. This is not the behaviour of dead CPUs or GPUs i saw before but i'm no pro.
All coils on sys_rail show 3 ohm. I removed nearly all mosfets on the board to test them in diode mode and all...Leave a comment:
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I have several coils around GPU and CPU showing 3-8 Ohm. I lifted the CPU coil and injected 1v with 1a on the 3 Ohm pad. Got directly 1V and 1A drawn but CPU went to 25-30C in the center.
So this is no short or am i wrong?Leave a comment:
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Sorry, was a bit busy but now have time to work on this board again.
ACN 8Ohm
ACP 8Ohm
I removed both mosfets from the board and they work normal and show no strange behaviour. Onboard i only get 6 MOhm. With second mosfet removed i get 20v on drain and source of first fet. When both are onboard only 20v on drain of first and nothing else....Leave a comment:
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Schematic, Boardview and maybe high res Pics of Minisforum NAB9
Hi all,
i got a NAB9 with some blown up components.
So schematic and boardview or maybe some good detailed pictures would be a big help.
I also added pictures of the areas. Second picture is close to the SSD connector.
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No i only get 2,74v with the diode removed. With the diode i get 1,7v and 20v on drain of first DC mosfet. Removed i get 2,74v and the mosfet is pulsing under the thermal cam but there is not anything getting through it. Single pin has 4v and goes to the 822 resistor(one side 4v and other 20v).
I also made some more measurements on the BQ chip:
VCC 20v
ACDRV 0v
ACOK 0v
ACDET 2,74v
REGN 6v
CMPIN 0,3v
BATSRC 0,5-0,7v pulsing
BATDRV 0,155v
BATSRC 0,155v
SRV 0,155v
CMSRV 0-0,54v pulsing
Top right pin of the diode...Leave a comment:
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Hello mon2,
maybe you have any more hints or ideas? I replaced the JB2 which is a BAV99W but the behaviour went back to my 1,7v and no more pulsing on first fet. :-/...Leave a comment:
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Finally some news. I unsoldered the JB2 ?diode? and finally got my 2,7v on pin 6 back.
But! the board is still not working. At the moment i can see that the first DC mosfets tries to switch and stops and does this in a loop. My guess is that it could be a reverse protection diode or p channel mosfet and without it there is no final go. So any ideas on this theorie and maybe anybody can help with replacement identification?
Also second mosfet (was also replaced to test if behaviour changes) is still showing 0,49v and 1,3v and has 2 Ohm on source. But it's connected to system rails...Leave a comment:
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Okay maybe i got the right twist now. Since i have 20v and 0,7v on the 822 resistor something is dragging down on the other side and this point goes to the battery area.
The diode on my pic shows voltages in every direction and i have a e7ej tantalum cap (not tue one one my pic) next to the battery connector which is the only one one the Board with no continuity. So could this be the cause?
Any information about the precise specs for the diode?...Leave a comment:
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19k Ohm...Leave a comment:
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Ah sorry my description was bad. I meant 2,7v with the calculator and my replaced resistors. Problem still is the same with 1,7v on pin 6. :-/...Leave a comment:
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I forgot to mention that 43T next to the 10 Ohm resistor should be the BAT54CW from your second pic. Diode mode shows normal values. I also changed my high and low side resistor with same values (high 127k and low 20k). I`m coming out at 2,7v or is the tolerance too big with 0,3v and needs to be adjusted? Normally between 2,4 and 3,1v should be fine.
I marked everything in the picture. Any other ideas?
...Leave a comment:
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Sorry it took some more reading to get everything right, im still learning.
I removed the high side resistor and it shows 127k and my low side removed 20k so calculated it should be around 2,7v and fine. The resistors are not my problem any longer and something else is dragging down here?...Leave a comment:
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