TUF505DT : No charge

[Sephir0th]

Re: TUF505DT : No charge

Okay, so communication between board and batery is ok.

Although 25V at ACDRV looks fine, I guess it doesn't harm to check the DC-IN Mosfets in addition for internal short.

[kurtspirit]

Re: TUF505DT : No charge

I try to find what happened but to be honest, i follow what mon2 and you telI am what mon2 and you tell me. I'm not too electronically savvy.

Anyway, the mosfets seem ok, which bothers me even more... Could the IC I changed, the BQ24780S, be out of order?

[Sephir0th]

Re: TUF505DT : No charge

I try to find what happened but to be honest, i follow what mon2 and you telI am what mon2 and you tell me. I'm not too electronically savvy.

Anyway, the mosfets seem ok, which bothers me even more... Could the IC I changed, the BQ24780S, be out of order?

"The mosfets seems okay" -->> You mean the DC-IN mosfets or the other three mosfets mentioned by mon2? Any measurements?

I don't think the charging controller is the culprit here since the board basically works, except you're not concinced about your soldering skills.

[mon2]

Re: TUF505DT : No charge

The source & drain resistance values = 0.90k = 900 ohms ? That is very low.

Reverse the meter leads and confirm this value again.

[kurtspirit]

Re: TUF505DT : No charge

Ok, to be more accurate :

source (1-2-3) & drain (5-6-7-8)

Left (not on board): black probe on Drain and Red on Source : 1.43K - Reverse : decrease from 13mohm
Top : black probe on Drain and Red on Source : 6K (sometimes 2K oO) - Reverse : decrease from 300K
Right : black probe on Drain and Red on Source : 6K (sometimes 2K oO) - Reverse : decrease from 300K

source (1-2-3) & gate (4)

Left :black probe on SOURCE and Red on GATE : OL - Reverse : OL
Top : black probe on SOURCE and Red on GATE : OL - Reverse : OL
Right : black probe on SOURCE and Red on GATE : OL - Reverse : 82K

gate (4) & drain (5-6-7-8)[/B]

Left : black probe on GATE and Red on DRAIN : OL- Reverse : OL
Top : black probe on GATE and Red on DRAIN : OL - Reverse : OL
Right : black probe on GATE and Red on DRAIN : 1mohm decrease- Reverse : OL

[kurtspirit]

Re: TUF505DT : No charge

Hello,

I hope someone is still here to give me ideas
Took a little time as I ordered multiple items. So I changed the 3 mosfets as well as the BQ purchased from Mouser and the result is no better...
I really do not understand what is happening but I can now rule out 99.99% a problem on these 4 components.
Having no diagram or boardview, I don't know where to look or what to measure :/

Thank you very much in advance. Your help is really much appreciated.

[mon2]

Re: TUF505DT : No charge

Apply the adapter and the battery.

Power on.

Carefully measure the voltage to ground of each pin of the charger IC.

Post your measurements with the pin numbers.

[kurtspirit]

Re: TUF505DT : No charge

Hi,
Thank you for your reply.

Here are the measurements :

1 - ACN : 19.41V
2 - ACP : 20.23V
3 - CMSRC : 20,02V
4 - ACDRV : 25.33V
5 - ACOK : 3.123V
6 - ACDET : 2.741V
7 - IADP : 3,204V
8 - IDCHG : 0.015V
9 - PMON : 0.336V
10 : PROCHOT :0.00V
11 - SDA : 3.280V ~
12 - SCL : 3.280V ~
13 : CMPIN : 2.00V
14 : CMPOUT : 4.921V
15 : BATPRES : 0.00V
16 : TB_STAT : 0.273V
17 : BATSRC : 11.13V
18 : BATDRV : 10.61V
19 : SRN : 10.61V
20 : SRP : 10.61V
21 : ILIM : 3.138V
22 : GND :0.00V
23 : L0DRV : 0.00V
24 : REGN : 5.998V
25 : BTST : 10.34V
26 : HIDRV : 10.62V
27 : PHASE : 10.62V
28 : VCC : 19.90V

[mon2]

Re: TUF505DT : No charge

To me, pin # 10 stick out.

This is an active LOW signal. If LOW, there is something wrong.

See attached from one of the datasheets by TI.

Remove all power. Meter in resistance mode. Measure the resistance to ground of pin #10.

Next, meter in DIODE mode.

Red meter probe, yes RED to ground.
Black meter probe to pin #10 of the charger IC.

Post each measurement.

[kurtspirit]

Re: TUF505DT : No charge

In resistance mode, i find 112,6kohm
In Diode mode : red probe on ground : 0.554 and black probe on ground: OL

[Sephir0th]

Re: TUF505DT : No charge

In my opinion ILIM stands out too. Would more expect something around 1V than even 3V. You could check PR8913 and PR8914 for beeing inside the specs

[kurtspirit]

Re: TUF505DT : No charge

Hi,
Thank you but what is PR8913 / PR8914 please ? I don't have any diagram or boardview :/

[piernov]

Re: TUF505DT : No charge

1 - ACN : 19.41V
2 - ACP : 20.23V

Voltage drop too high

7 - IADP : 3,204V

Saturated as a result

[kurtspirit]

Re: TUF505DT : No charge

Ok and what do you think about ? Have you an idea ? Thanks very much

[kurtspirit]

Re: TUF505DT : No charge

I still stuck with this charging issue :/ Is someone have a boardview for this laptop please?
I don't understand what happen with this case. Thank you very much.

[mon2]

Re: TUF505DT : No charge

Remove all power. Meter in resistance mode.

Check the resistance to ground of ACN pin.

Post the measurement.

[kurtspirit]

Re: TUF505DT : No charge

I find 85kohm between ground and ACN

[mon2]

Re: TUF505DT : No charge

So no short on the main power rail.

Measure the resistance between ACN & ACP pins. What is the resistance of the current sense resistor?

There should not be such a large voltage drop from ACP to ACN pins.

Perhaps you can measure the voltage to ground again of each of these pins and post your updates.

[kurtspirit]

Re: TUF505DT : No charge

Ok, so resistance between ACN and ACP is : 168.5kohm

Here are the latest measurements from ground to each pin :

1 - ACN : 19.41V
2 - ACP : 20.23V
3 - CMSRC : 20,02V
4 - ACDRV : 25.38V
5 - ACOK : 3.123V
6 - ACDET : 2.741V
7 - IADP : 3,204V
8 - IDCHG : 0.100V
9 - PMON : 0.030V
10 : PROCHOT :0.00V
11 - SDA : 3.280V ~
12 - SCL : 3.280V ~
13 : CMPIN : 2.00V
14 : CMPOUT : 4.924V
15 : BATPRES : 0.00V
16 : TB_STAT : 0.100V
17 : BATSRC : 11.12V
18 : BATDRV : 11.12V
19 : SRN : 11.12V
20 : SRP : 11.12V
21 : ILIM : 3.141V
22 : GND :0.00V
23 : L0DRV : 0.00V
24 : REGN : 5.999V
25 : BTST : 10.84V
26 : HIDRV : 11.12V
27 : PHASE : 11.12V
28 : VCC : 19.90V

[mon2]

Re: TUF505DT : No charge

OMG...can you check the acn to acp resistance again?

Waaaay too high. Check the schematics (not at my desk now) but it should be ~1ohm or less.

This is a serious fault if the reading is accurate.