Laptop

Maintenance HP 520 1

mahmoud 2020-04-23 3 دقيقة قراءة

When a peer to take over 520 repair, saying it was 1.05 of a voltage did not come out. Power to 0. 16A of the power-down. Blink a bold look at short-circuit. So the board clean-up clean, according to the amount of time that the power switch. Sure enough, yes 1. 05V did not come out. This chip TPS51124 issued a two-way power supply, all the way to 1. 5V, all the way to 1. 05V, several colleagues said the change, and to no avail. Since the initial judgments 1. 5V out, then the chip, the main power supply and 1. 5V of the EN signal to normal, VBST also no problem. The problem is more evident. 1.05 The EN did not come out. Verify the next 23PIN EN signal VCCP-ON does not. The amount of PR180 and PC129OK, determine the VCCP-ON is in front of the circuit gives the signal.

Pursue this line of PVCC-OK after a few transis tors and a linear regulator chip conversion. PVCC-OK with the amount of

U22’s 12PIN a 3. 3V output, +3 VS through a resistor there would be no VCCP-ON signal, is preparing to repair the signal, I suddenly thought of

PWR-GD of this signal, if the U22 is a problem, then the signal does not appear, the amount of PWR-GD not, try to clamp the +3 VS and go to VCCP-ON, the power to the 0.26 power-down, 1.05 out. Almost detours, and seems to issue or lies in the PWR-GD signal here. The PG signal to the CPU-management chip enable signal used to do, J6 is connected with the Q36, and the PER-GD repair them then enable VCCP-ON signal also out. The amount of U22 to 10 feet. 14 feet. 12 foot all 3. 3V output, 6 feet is not. The 6 pin is the diode conduction through a 3.3 for the PG, this is obviously a new problem. Otherwise U22 bad, to be in front of the load does not supply conditions, the volume of supply in this way power transistor +2. 5, +5, +3. 3, +1. 5 a lot. Problem identified, U22 removed look at the original U22 was not bad, is not peer into the following pads are engaged in off-off puzzle puzzle, the following inside of the pad pins are touched together, and to effect positive pad six feet away when the direct, and make up and not come back, the chip that 5.6 feet touched on out. Do not have the material plate ah, Nanjing SB customers never seem to give the time. Night is necessary to, or repair Jiuji others. There is no way, Zhujiang the competition is too high. Only change lines, clamp and U22’s 12 feet 6 feet, take a look at the direct pull-up voltage, power-on to the 0. 9A, hanging open 1. 05V power to the test point 0. 69A, was originally VCCP-ON pulled at the end of the PG, each with 1. 9,1. 6V of. This driver can not load after the class. Then I would be a two-way splitter out, removed Q35, Q36. Q42, the U22 fly line 12 directly connected to the U22 diode D32, remove PR2244 resistance, U22 10 feet directly Q42D very lucky to 5 feet hanging out a little, with the starting line then PR415. OK power-normal, baking machine for a while away. Go back to set a U22, back to the customer replaced, in the dismantling of the transistor to save the original good.

mahmoud

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