Hi, to come back to this laptop. I still had this laying around and because I couldn't sleep I picked this repair up, it's been a long time, but the owner bought a new on back when it broke, and didn't expect a repair. But I could not believe the 19v rail would directly warm up the CPU with voltage injection.
So what I did was remove the bridges PJP8101 and PJP8102 to isolate the 2 sides of the board.
The short was on P_IMVP9.1_VCCCORE_VIN_S
I injected 1V 3A on that side of the board, but again only CPU/PCH warmed up slightly after 15min.
So my guess was one of the...
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it was pre-flashed by the seller. After replacement all voltages were fine and the device startsup and charges.
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I decided to order a new IT8528G and give it a try, after couple of weeks waiting the chip arrived, and now the problem is solved.
So the initial problem was the IT8528G.
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Hello,
In this link you can find the schematic and boardview:
[url]https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/schematic-requests-only/99512-lcfc-s550-nm-c811[/url]
Look in the boardviewer for the net 'PLT_RST#' and you will easily find all components that are part of 'PLT_RST#'. You can then measure voltage and resistance to ground.
In my case I fixed the laptop with flashing the bios. This is 1.8v bios, and you have to desolder the chip from the board to...
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If I follow the power sequence, first in line that has 0V is VCCDSW_EN
maybe it is a defective U3601 (IT8528G).
I found this topic on this forum with a comparable problem:
[url]https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/94230-surface-pro-4-doesn-t-turn-on[/url]
I'm just thinking out loud, the changes in voltages after 1 minute must be something controlling this... maybe this IChttps://If I follow the power sequen...is a defective
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Yes, that is the one, but it measures fine when I take it off the board
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VDD_BATA_PACK seems good, I checked PD5501 and D7403, they don't leak.
I checked all PD parts on the board and find a leak on PD7501 (tested with PD on the board).
Red probe on Anode is 0.273 and Red probe on Katode is 1.043
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I just removed those 4 load switches, but the problem remains, I think I have to further investigate this 5v system
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After removing U6403 the short is gone. When plugging in the charger, the symptoms remain the same but the 5V is now 0.91V for the first minute. Then goes back to 0V.
I probably have to source replacement for U6403 to do further tests.
I measured resistance between all pins of U6403 on the bench, but find no low resistance between pin 5/7 (gnd) to other pins.
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I injected 1v @ 3a, but nothing is heating or warming up (not even after 15mins). The system only pulls 0,09amps.
Some parts are difficult to reach because they are underneath the frames that hold the metal caps. But I used IPA alcohol to check for heat dispense.
I don't know if raising the voltage is safe? Otherwise I'd think to remove the load switches one by one and test if the short is gone.
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I checked the above components very close, but no visible damage.
I'm thinking of injecting 1v 3a on this rail to search for a short....
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+3P3VSB_REG = 13kOhms
+5VSB_REG = 12.3Ohms (not sure how I missed this yesterday)
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Microsoft Surface Pro 4 1724 no power
Hello,
This tablet has no power, no visual signs of corrosion or burned components.
I notice V_ALWAY_ON_IN on PD5501 and PD5506 is 12V.
But VDD_BATA_PACK on PD5501 is 2.05V when the charger is plugged in, after a little over 1 minute VDD_BATA_PACK goes up to 6.16V
FANG_PWR_F stays 0V.
+3P3VSB_REG is only 1.98V
+5VSB_REG is 0V
I cannot find shorted coils or coils with low resistance to ground except for the ones close to the PCH/CPU.
Link to boardview and schematics:
[url]https://www.badcaps.net/forum/troubleshooting-ha...
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got it fixed, flashed bios again with a TL-866 II programmer instead of CH341A. System works now.
Which is weird, with CH341A read, write and verify would complete without error
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Ok, found out PLT_RST# is missing, so further looking in to that.
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Lenovo Ideapad 5 15ARE05 - no post
Hello,
I have Ideapad 5 15ARE05 which turns on, but no post or display. No reaction on capslock or numlock.
All voltages seem to be fine on all the coils. I thought bios could be corrupt, but flashed with several versions from this forum with no succes.
CPU gets hot fast, and has only onboard memory, no ram slot.
I'm thinking bad cpu/gpu or ram, but no possibility to test. Or could this be a problem with the EC ?
Thanks
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MSI GL72 Board MS-16J91 - no 1_2VDIMM
Hello,
I'm looking for some assistance for a MS-16J91 board. When the adapter is plugged in, the powerled flashes slowly 3 times.
19v main rail is always present, +3VALW and +5VALW are always present.
+3v and +5v on the coils and +3.3v on bios chip are active untill the powerled goes off.
Following the power sequence after +3 and +5 comes +1.2v for dimm on choke 9 I only have 0.1v.
Drain of Q22 is 19v
Source and gate are 0.1v
I tested Q22 and Q25 on the board in diode mode, and they look ok.
Maybe PU5 is the problem, but don't...
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I replaced the U8050 and PPBUS_G3H stays 13.08v, I have 13.08v coming in on pins 1 + 2 on U8050, but no output.
My probes of my multimeter are not small enough to measure pin 3 and 4 on U8050 without touching other parts.
Pin 5 to 8 are 0v.
I'm not a pro in reading schematics, but if I'm right, U7800 is switching the gates on U8050.
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I removed U8050: measured on the mosfet on table:
I have a 2 Ohm resistance from pin 3 to pin 9 (switching probes is same resistance)
And 1.6 Ohm resistance from pin 6 + 7 + 8 to pin 9
With U8050 removed, there is no continuity from F7000 pin 2 to L8050.
With power to the board I now have 13.08V on both sides of F7000.
So I think U8050 is bad....
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