U1200 is "System Power Management"....
abajor
Senior Member
Last Activity: Today, 12:03 AM
Joined: 02-08-2024
Location: Santa Rosa, CA
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Its not the only thing that gets "hot" but it's the hottest thing on the board as can be seen in attached thermal image.
U1200 is "System Power Management".... -
A1990 820-01814A U1200 very hot when powered up, USB drawing > 4A
I have this machine. It powers up and gets fan spin, will even shut down when I hold the power button.
U1200 gets very hot under thermal camera, the next hottest region is UB000 and L7030. I'm assuming L7030 is warm due to charging.
Do I have a potential dead CPU? or just a dead U1200? Not sure what to check since everything is powered up. -
Thanks, I had to pass on doing anything further with this one....Leave a comment:
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Anybody here have any suggestions on what to check for PP3v3_G3H_RTC_X diode drop issue? I've tried to dig through the schematic there are many devices on this rail I don't want to blindly start removing components until I find what is messing up the diode drop. Reverse voltage injection isn't helpful as I described in my initial post.Leave a comment:
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Just for an update I sent it to a place with an ultrasonic cleaner and the machine works.Leave a comment:
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Asus G634j Rog Strix SCAR Power rail shorted nothing hot on thermal camera.
I haven't been able to find a schematic or board view for one of these out in the wild. I had one come in with a no charge/no boot issue.
It Uses two pairs of Source to Source Mosfets after the power jack to prevent back flow from battery or PSU after the power jack.
The drain on the board feed side of the Mosfets measures a near dead short to ground. I attempted a voltage injection there it draws about 1.4A at 1V absolutely nothing heats up on the thermal camera.
It draws 1.86A injecting directly to ground.
Is this just the way it is when these ultra... -
So learning the hard way I removed all of the VRAM chips, not sure if they use some special formulation of solder for the BGA but they were very difficult to desolder, ripped a few pads I need to now fix with micron wire.
The really odd thing is after removing all six of the VRAM chips I found that the circuit still has a resistance of around 56ohm. Very odd for a power rail with no load devices and no buck converter mosfets installed.
I didn't realize I needed 6 VRAM for this board so I'll have to wait to go any further with it. Wondering about this 56ohm resistance I'm measuring...Leave a comment:
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A2141 PP3v3_G3H_RTC_X Diode Reading .104V Voltage 3.39V
Have an A2141 which is reading about 5.2V 0.07A on all USB jacks, started doing the measurements.
PPBUS_3GH diode: measures good .45V
PPBUS_3GH Voltage: maybe not so good 12.25V maybe bad T2? Unit did not come up in DFU on configurator.
The weird so far is
PP3v3_G3H_RTC_X diode: .104V (WTF?)
PP3v3_G3H_RTC_X voltage: 3.39V (Normal)
Stopped there attempted reverse voltage injection at PP3v3_G3H_RTC_X with 1V. Instead of the circuit sinking any current, My PSU suddenly reads 3.4V with no current draw.
Not sure what any of this means... -
Unfortunately no.
Wasn't able to identify where the other issue was coming from....Leave a comment:
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I'm about to order some mosfets for the VRAM power stage, I'm wondering what a typical DCR of the VRAM "+FBVDDQ" voltage rail should be to ground? I do have concerns that the VRAM is damaged since the buck converter mostfet was shorted, and the thermally varying DCR is coming from the VRAM itself....Leave a comment:
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Found the problem.
It's one of these [url]https://www.digikey.com/en/products/detail/onsemi/FDPC5018SG/5305044[/url]
High Side / Low Side buck converter mosfet packages for powering the V-RAM rails.
The only way I figured out what the components were was watching the resistance drop as I blew hot air in the region of the VRAM. It's pretty wild that the mosfet package itself doesn't heat up when I inject current into the board, but the resistance drops as I pump heat into the traces.
I'm surprised this is what failed, I almost wonder if the buck converter...Leave a comment:
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It looks like +NVVDD might be shorted I'm measuring a DCR of 0.6 Ohm. I don't know for sure I know there are a huge amount of parallel connections in a GPU so perhaps 0.6 Ohm is perfectly normal across the GPU power rail?
+VDDCR_SOC measures 9.6 Ohm.Leave a comment:
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Thankfully I was able to find a Schematic on my board schematic service which says it is the GA401QM version of the motherboard. My best guess at the moment is that its one of the APU power IC's since that's the only power IC that has a direct connection to ground which receives AC_BAT_SYS, also I did confirm that PVDD_AMP is just AC_BAT_SYS with a couple of fuses and some filter caps separating the two rail designations, so still could be something there as well....Leave a comment:
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Thanks I already took out PQH8901, PQL8901 and PQ8903 The three largest N-Channel Mosfets in the area. For what ever reason I can only find a board view for this part number not a schematic so it's extra exciting hunting and pecking for related circuits.
I'm assuming PVDD_AMP and AC_BAT_SYS are a parallel source since they both exhibit the same resistance to ground....Leave a comment:
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ASUS Zephyrus GA401IV 1.4 GA401IU MB._8G_R7-4800S_AS_R1.4fz AC_BAT_SYS ~32Ohms
I have an ASUS Zephyrus board on which the owner shorted the battery clip to a the small filter cap which goes across the "BAT" connections 1 2 and 3 to ground, and one one of the TVS diodes is missing.
Other than the small .1uF cap which was blasted off its pads and the missing TVS diode everything appears fine.
How ever when I get to the AC_BAT_SYS section I read between 28-33ohms to ground (this depends on how warm I've made the area). I'm also reading the same thing across +PVDD_AMP capacitors.
I have tried to inject 1V into AC_BAT_SYS. I draw about .15A,... -
A3401 Gatorade Spill Best next steps
I had a customer call me with an M4 A3401 her daughter spilled a gatorade into, and didn't tell her mom for about 2 hours.
I had her bring it in immediately so we could disconnect the battery and I could dismantle it so I could swab the board with Isopropyl an dry with a heat gun.
There was already some green copper corrosion when I opened it.
I did a good first pass and dried off the board, now I'm going over it with my scope swabbing and poking at any oxides with my exacto tip.
I brought out my hot air tool to evaporate the iso and caramelized sugars started bubbling... -
A2251 L8100 Diode Drop .009V Resistance 2.6Ohm
Trouble shooting an A2251, it is giving me the behavior that all three USB jacks except the DFU port are reading 5.18V .24A, the DFU port draws no current.
Tried swapping that CD3217 from a donor, that changed to DFU port same behavior the adjacent USB port is now boot cycling, other side un effected.
Hindsight probably should have checked the diode drops first.
I removed L8100 to confirm that the PP1v1_S3 rail was "shorted" It reads about 2.4ohm and .009V on diode drop. The HighSide Low Side FETS before L8100 appear to be fine. Proper diode... -
So this is weird I'm not sure what to make of it. On this board PP2v5_nand_ssd0 was reading as a short.
There was a little corrosion schmutz around U9580 I removed U9580 still saw a short on PP2V5.
Decided I would do voltage injection on the rail. I thought I saw a current limit flash on my psu out the corner of my eye but the rail wasn't drawing any current.
Now I go back to measure resistance without U9580 and it is reading 5M ohm across PP2V5.
I'm assuming I just blasted a little corrosion off somewhere? Got to love catastrophic liquid damage....Leave a comment:
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A2141 No audio on speakers, yes audio on headphone jacks.
I just can't escape Apples most CURSED laptop the dreaded A2141.
Can't find any info on this speaker problem. I've been digging through the schematics and found there's a separate chip U6300 to drive the headphone jack.
It appears all of the audio signal is transmitted using i2S. It's pretty wild that the internal speakers have 3 amplifiers each. I'm assuming whatever provides the clock or routes the signal to the speaker amps has an issue?
U3900 is as far as I've gotten in my exploration.
Anybody know this issue? Is it fixable? U3900 looks like something... -
I tried flowing a little tacky flux first to make a thin layer then stuck the balls down, but it's impossible to keep them from moving once the flux liquifies. So that was an exciting lesson learned.
I ordered one of the BGA stencil kits [url]https://www.ebay.com/itm/363405380082?chn=ps&google_free_listing_action=view_item&gQT=2[/url]
Its not clear whether the stencil is thick enough to just use solder paste or if I need to use balls.
I'm a little confused about the "tin" balls I got. Do they use pure tin for repair? The melting point...Leave a comment:
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