Hi, I have a M17x R4 board here that doesn't power on, the first thing i checked was power button and BIOS voltages.
Power button was around 19v :/ and bios was at 0v, so not even close here.
After poking around on the board with the help of schematics (In attachement)
I've found out that the PQ27 and PQ28 (3.3v and 5v high side mosfets) werent outputting anything, both gates were at 0V.
Further digging showed that both +5VALWP and +3VALWP had 13ohm resistance to ground only.
I've removed PL10 and PL11, PC58 and PC63, desoldered all of the PJP3-PJP6 jumpers.
Still showing 13 ohms when i check positive pad of PC58 or PC63 to GND.
From what i understood from schematics the only way to have path to ground is via the PU4 (PSU Controller)... when i removed it it showed that there is open line on same points as was 13 ohms before. I've checked the VO1 and VO2 (PINs 24/7) out of circuit and they both have resistance in 100+ kOhms, putting the chip back in the board and the resistance drops to 2kOhms, plugging in ac and BAM, back to 13ohm...
Here are the readings on PU4 when it's in circuit, shich all seem ok except the ones that are 0, but shouldn't be.
EN is 3.13V
REF, TONSEL, SKIPSEL are all 2V
VREG3 is 3.3V
VREG5 is 5V
BOOT1 and BOOT2 are 4.55V both
VIN is 19.5V
everything else is 0V
What am i missing here?
Any help appreciated.
Power button was around 19v :/ and bios was at 0v, so not even close here.
After poking around on the board with the help of schematics (In attachement)
I've found out that the PQ27 and PQ28 (3.3v and 5v high side mosfets) werent outputting anything, both gates were at 0V.
Further digging showed that both +5VALWP and +3VALWP had 13ohm resistance to ground only.
I've removed PL10 and PL11, PC58 and PC63, desoldered all of the PJP3-PJP6 jumpers.
Still showing 13 ohms when i check positive pad of PC58 or PC63 to GND.
From what i understood from schematics the only way to have path to ground is via the PU4 (PSU Controller)... when i removed it it showed that there is open line on same points as was 13 ohms before. I've checked the VO1 and VO2 (PINs 24/7) out of circuit and they both have resistance in 100+ kOhms, putting the chip back in the board and the resistance drops to 2kOhms, plugging in ac and BAM, back to 13ohm...
Here are the readings on PU4 when it's in circuit, shich all seem ok except the ones that are 0, but shouldn't be.
EN is 3.13V
REF, TONSEL, SKIPSEL are all 2V
VREG3 is 3.3V
VREG5 is 5V
BOOT1 and BOOT2 are 4.55V both
VIN is 19.5V
everything else is 0V
What am i missing here?
Any help appreciated.
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