nicoar10
Member
Last Activity: 01-30-2026, 07:16 AM
Joined: 12-09-2024
Location: madrid
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Take diode values in LVDS connector focus in EDP lines.... -
HP DAG7HAMB8F0 rev F NO IMAGE/NO BACKLIGHT internal display but works HDMI
Hello! In this case I have an HP with motherboard DAG7HAMB8F0 rev F. The laptop powers on and shows video on an external display, but not on the internal screen. There is no image / no backlight.
I have checked and I do have 3.3 V at the display connector. There is also no short circuit at the display connector. I have checked the 3 V and backlight fuses and they are OK.
What I can’t understand from this schematic is that I cannot find the backlight boost circuit. According to the schematic, this display works with the same VIN supply, which passes through a fuse and... -
great!!Leave a comment:
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It works! Thank you very much for your help. It has been quite a challenge....
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i will use this. looks simillar . is it ok ?...
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PL0201 no voltage
Could be bad PQ0201 too ?...Leave a comment:
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PL0201 no voltage with battery connected
No change
...
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Ok, thank you very much for your help. Unfortunately, I don’t work much with PCs, but with Macs, so I don’t have many spare components. I have checked the charging circuit of a MacBook Pro, and the configuration is quite similar. Do you think this dual N-channel MOSFET could work?...
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About 1.5 , 2v both sidesLeave a comment:
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Not shorted...Leave a comment:
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Yes Sr is BQ25700A both
If i connect battery i have 20v 0 current , orange light and fan spin for some seconds.
I have all pins volt
1- 20
2- 20
3- 20
4- 0
5- 0
6- 2,1
7- 6v
8- 0v
9- 3.7
10-0
11- 0
12- 3.3
13- 3,5
14-0
15- 4,5
16-0
17- 1,35
18-3,49
19-0
20-0
21- 19,68
22- 19,68
23- 20v
24- 20v
25- 20v
26- 0v
27- 0v
28-6v
29- 0v
30-19v
31-20v
32-20v
All...Leave a comment:
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Same measurement with ot without PQ0204
This is a "new" BQ ic charger but i have some more to try.
just a note, laptop arrived with same behavior
thanks...Leave a comment:
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you mean PR0227 = 3.V3 BOTH SIDES
PR0231 3.3 ONE SIDE 3.3 , OTHER 0V
or what other pull up resistor ?
EDIT:
I checked PQ0204 and it´s ok . I found other similar ic in the board...Leave a comment:
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Thanks for your reply
R0227 / R0231 checked and 100k both.
Probably bad PQ0204 ?...Leave a comment:
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CHRG_OK : DIODE = 0.100 VOLT = 0.15MV
VDDA: DIODE 0.554 VOLT = 6V
Is the power adapter of the proper rating? yes
Voltage of REGN? VBUS?
REGN = 6V
VBUS = 20V
VCC3SW = 3.3v
PR0227 = 3.V3 BOTH SIDES
PR0231 3.3 ONE SIDE 3.3 , OTHER 0V
LX1_CHG = 20V
LX2_CHG = 20V...Leave a comment:
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I let you know tomorrow. Just to add, genuine charger, orange light active . ThanksLeave a comment:
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Lenovo T480 20v no current and only works from battery
I’m checking a Lenovo motherboard, board number NM-B901, with the following issue.
When connected to the USB-C charger it shows 20V with a current draw of 0.00, sometimes 0.40. Even so, the charger generates the main voltages, and when the power button is pressed it attempts to turn on — the fan spins for a few seconds and then stops, without displaying video.
With its battery connected it works correctly: it powers on, displays video, and shows an image on the screen. The problem is that it does not charge the battery.
I have checked all the MOSFETs and they are fine.... -
FIXED!
MISSING PBUS SENSE LINE...Leave a comment:
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820-02337 MBP M2 strange behavior. No S2 Voltage present
Hello, I’m checking a board 820-02773 that arrived showing 5V and a consumption of 0.40A. Present voltages: PPBUS: 12.3V, PP3V08_AON: 3.8V, 5V_AON: 5V. I also have 3.3_UPC present on the USB controllers.
The problem is that I don’t have any S2 voltage present on the motherboard. The PMIC U8100 is not sending out the LDO voltages. Even so, the PMIC is being powered correctly with 3.8V, and its 3.8V and 5V boost voltages are present, as well as its 32kHz clock. However, none of the buck or LDO rails are present.
I’ve tried replacing the PMIC, but the result is the...
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