HP Pavilion x360 Convertible - Identify shorted Power IC

[CircuitRehab]

I've been working on a HP Pavilion x360 convertible that is showing no signs of life; It was brought to me by an IT repair shop as they do not work on motherboards.

The first component on the board I replaced was the KB9028Q Power Management Chip. The chip was getting very warm as soon as power was connected to the board, but it seems fine now after replacement.

I've now identified another chip on the board that is getting very hot, but I cannot seem to find any information about the chip anywhere. The chip has the name "BABARB" but no other information. There are some numbers surrounding the chip (PU4501, ED6304, PL4501) but I haven't had much luck looking up those numbers.

I definitely believe this chip is on the main power rail, as on one other pins I'm getting 19V (same as DC in), I just can't seem to find a replacement anywhere. I've removed almost all caps in the surrounding area to see if a bad cap was causing the heat, but it's definitely the chip.

Any help and or advice would be appreciated!

[SMDFlea]

Re: HP Pavilion x360 Convertible - Identify shorted Power IC

Possibly a silergy SY8288BRAC - https://www.badcaps.net/forum/showpo...23&postcount=1

ID your motherboard by looking for a white silkscreened part number and use the forum search to find if the schematic is available or has been posted

https://www.badcaps.net/forum/showthread.php?t=88758

1.1.3 Motherboard model number .

Test the voltage on all pins then without power test exact resistance to ground on all pins and post your measurements .

[CircuitRehab]

Re: HP Pavilion x360 Convertible - Identify shorted Power IC

Possibly a silergy SY8288BRAC - https://www.badcaps.net/forum/showpo...23&postcount=1

ID your motherboard by looking for a white silkscreened part number and use the forum search to find if the schematic is available or has been posted

https://www.badcaps.net/forum/showthread.php?t=88758

1.1.3 Motherboard model number .

Test the voltage on all pins then without power test exact resistance to ground on all pins and post your measurements .

Thank you for your reply. Here are some measurements I've just taken.

PIN 1 - 2.95V
PIN 2 - 19.36V
PIN 3 - 19.36
PIN 4 - 0.50
PIN 5 - 19.36
PIN 6 - 0V
PIN 7 - 0V
PIN 8 -0V
PIN 9 - 0V
PIN 10 - 0V
PIN 11 - 0.27V
PIN 12 - 0.3V
PIN 13 - 0.08V
PIN 14 - 0.04V
PIN 15 - 1.27V
PIN 16 - 3.23 V
PIN 17 - 3.27V
PIN 18 - 0V
PIN 19 - 0V
PIN 20 - 0V

Resistance to Ground

PIN 1 - 0.5 MΩ
PIN 2 - OL
PIN 3 - OL
PIN 4 - OL
PIN 5 - 2.0MΩ
PIN 6 - GND
PIN 7 - GND
PIN 8 - 100 KΩ
PIN 9 - 100 KΩ
PIN 10 - 0.9 MΩ
PIN 11 - 0.9 MΩ
PIN 12 - OL
PIN 13 - 18 Ω
PIN 14 - OL
PIN 15 - 9.2 KΩ
PIN 16 - 9.2 KΩ
PIN 17 - GND
PIN 18 - 2.2 MΩ
PIN 19 - 2.2 MΩ
PIN 20 - 2.2 MΩ

[CesarTurboPC]

Re: HP Pavilion x360 Convertible - Identify shorted Power IC

Thank you for your reply. Here are some measurements I've just taken.

PIN 1 - 2.95V
PIN 2 - 19.36V
PIN 3 - 19.36
PIN 4 - 0.50
PIN 5 - 19.36
PIN 6 - 0V
PIN 7 - 0V
PIN 8 -0V
PIN 9 - 0V
PIN 10 - 0V
PIN 11 - 0.27V
PIN 12 - 0.3V
PIN 13 - 0.08V
PIN 14 - 0.04V
PIN 15 - 1.27V
PIN 16 - 3.23 V
PIN 17 - 3.27V
PIN 18 - 0V
PIN 19 - 0V
PIN 20 - 0V

Resistance to Ground

PIN 1 - 0.5 MΩ
PIN 2 - OL
PIN 3 - OL
PIN 4 - OL
PIN 5 - 2.0MΩ
PIN 6 - GND
PIN 7 - GND
PIN 8 - 100 KΩ
PIN 9 - 100 KΩ
PIN 10 - 0.9 MΩ
PIN 11 - 0.9 MΩ
PIN 12 - OL
PIN 13 - 18 Ω
PIN 14 - OL
PIN 15 - 9.2 KΩ
PIN 16 - 9.2 KΩ
PIN 17 - GND
PIN 18 - 2.2 MΩ
PIN 19 - 2.2 MΩ
PIN 20 - 2.2 MΩ

I know it's a little late but it may help.

PIN 1 -Boot-strap pin. Supply high side gate driver.
PIN 2 - PIN 3 - PIN 4 - PIN 5 - VIN
PIN 6 - PIN 19 - PIN 20 - The VOLTAGE depends on the circuit, commonly connected to the output coil. In the example image we have 3.3V. This happens when the equipment is turned on, while it is in stanby it has no voltage.
PIN 7 - PIN 8 - PIN 18 = GND
PIN 9 - Power good Indicator.
PIN 10 - PIN 16 - NC
PIN 11 - ENABLE2 = (STB = (R2/R1+R2) * Vin)
PIN 12 - ENABLE1 - EN2 and EN1 are required at high level for the circuit to start operating
PIN 13 - Output current limit threshold selection.
PIN 14 - Output feedback pin EJEMPLO (STB=0V / PW_SW=PIN6)
PIN 15 - External 3.3V bypass power supply input. Leave this pin floating if it is not used.
PIN 17 - Internal 3.3V LDO output. Power supply for internal analog circuits and driving

In the example image we see a SY8286 circuit and the voltages would be:

PIN 1 - STBY=3V
PIN 2 - PIN 3 - PIN 4 - PIN 5 - STBY=19V
PIN 6 - PIN 19 - PIN 20 - STBY=0V / PW_SW= 3.3V
PIN 7 - PIN 8 - PIN 18 = GND
PIN 9 - STBY=0V / PW_SW=3.3V
PIN 10 - PIN 16 - NC
PIN 11 - ENABLE2 = STBY = 4.5V
PIN 12 - ENABLE1 = STBY=0V / PW_SW=5V
PIN 13 - STBY=0V / PW_SW=1V
PIN 14 - STBY=0V / PW_SW=3.3V
PIN 15 - NC
PIN 17 - STBY=3.3V



Espero que sea de utilidad para ti ya que las computadoras nuevas, casi todas tienen estos circuitos