Dell E5550 No charge (charger unidentified)

[Vesko356]

Re: Dell E5550 No charge (charger unidentified)

Just to clear up the mystery,continuity should only be checked when the board is unpowered .See the attached picture,the board is an LA-9591P ,ive soldered wires to PQ2 pin 1 and 3, the board isn`t powered. PR7 isn`t populated and as theres no voltage at PQ2 pin 2 there`s no flow between D/S S/D and no continuity

With the board powered and PQ2 active then there will be continuity,you just can`t check it with a meter,you know its there though as it has voltage on pins 1 and 3.

Havn`t found my passport yet..

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Please check again the readings for me, set the meter to Ohm reading at the lowest scale (200Ohm). I just get readings from the same as Andreasbest board (ZAM80 LA-A911P Rev1.0 (A00)) and the readings are follows:
1. Unpowered board - no continuity (of course) between PL3 and PU1 pin3
2. Powered board - between pin1 and 3 of PQ2 - 21 Ohms, and 51.5 Ohms between PL3 and PU1 pin3 (this is a plus ~30 Ohms which is the resistance of the PR9 itself), so everything is as expected.

[SMDFlea]

Re: Dell E5550 No charge (charger unidentified)

Please check again the readings for me, set the meter to Ohm reading at the lowest scale (200Ohm). I just get readings from the same as Andreasbest board (ZAM80 LA-A911P Rev1.0 (A00)) and the readings are follows:
1. Unpowered board - no continuity (of course) between PL3 and PU1 pin3
2. Powered board - between pin1 and 3 of PQ2 - 21 Ohms, and 51.5 Ohms between PL3 and PU1 pin3 (this is a plus ~30 Ohms which is the resistance of the PR9 itself), so everything is as expected.

2. Powered board. No,its not the way to test resistance,it should be tested unpowered. The meter puts out a small ammount of current, and any other current from a live circuit will interfere with the readings and you can damage your meter with enough current.

[Vesko356]

Re: Dell E5550 No charge (charger unidentified)

2. Powered board. No,its not the way to test resistance

I agree, but in thins case there is no other way, without power PQ2 is off. Another indirect way to see continuity here is to measure voltage on pin3 of PU1.

The meter puts out a small ammount of current, and any other current from a live circuit will interfere with the readings and you can damage your meter with enough current.

Yes it's true in general, but here we don't measure resistance to ground but resistance in the line, and second it's a low voltage signal line with very small current, powered by ALW low current source through a 2.2K resistor, so I don't see any problems here.

[Ussovak]

Re: Dell E5550 No charge (charger unidentified)

Resistance measurements are always done with power OFF. Basic electronics.

[Inforgalaxie]

Re: Dell E5550 No charge (charger unidentified)

The SIO need to send the GPIO_PSID_SELECT in PU1 PIN6 correct?

I have the same problem on a dell but pin3 and pin 4 have 3.3v but pin6 0V...

It can be a SIO defect correct?

[mon2]

Re: Dell E5550 No charge (charger unidentified)

Attach the official power adapter. Measure the voltage to ground at PL3. Meter in dc volts scale of 20v or higher.

What is the reading?

[Sailman]

Re: Dell E5550 No charge (charger unidentified)

Remove pd5 and check if the laptop identify the charger (with an original Charger)
if it does replace pd5 (Common Problem)