LA-C501P No ACDRV??

[dspok]

Hello,

I have LA-C501P Mainboard in which VCC, ACDET are ok but NO ACDRV. Can anybody let me know what I'm missing?


Thanks,

[mon2]

Re: No ACDRV??

Hi.

1) post all voltage values on the charger IC @ PUB01. It is important to review. I posted a request for the detailed operation of the TI charger ICs on the TI forum and their engineer group replied with a great response.

You can find it here:

https://e2e.ti.com/support/power-man...114776#4114776

2) often faults are with the first 2 mosfets. You can confirm the status of the first 2 mosfets (aka DCin mosfets) by removing all power.

Meter in resistance mode.

Measure the resistance of each of the 2 x dcin mosfets as follows:

Source (1-2-3) & drain (5-6-7-8)
Source (1-2-3) & gate (4)
Gate (4) & drain (5-6-7-8)

Post each measurement and the meter scale used.

Repeat for the next mosfet.

[mcplslg123]

Re: No ACDRV??

CMSRC present??

[Udemzy]

Re: LA-C501P No ACDRV??

If PQB1 doesn't switch,how then will CMSRC generate? To switch the MOSFET then ACDRV must be generated.

The practical way to generate ACDRV.

Check the impedance of the ACFET and RBFET( on diode mode,it should be above 0.400)
ACN and ACP communication with CLR(very important)
Impedance of CMSRC
Impedance of CLR
Impedance of REGN,ACDET,ACOK

Voltage on VCC,ACDET,REGN and ACOK

[Udemzy]

Re: LA-C501P No ACDRV??

The reason why it's advisable to check the impedance first is because from experience, ACN and ACP communication with CLR is important, the communication line of ACN with CLR was broken (not communicating) and this caused the chip not to generate ACOk.

[mcplslg123]

Re: LA-C501P No ACDRV??

@Udemzy, The OP has not given any measurement for dc-in fets voltage readings, so not possible to conclude whether CMSRC is present or not. Say if dc-in mosfet is partially shorted, there will be cmsrc present but no ACDRV. This way we can get an idea whether dc-in fets are wrong or not as OP has not given any measuremnts which @mon2 advised.

[Udemzy]

Re: LA-C501P No ACDRV??

I was replying base on post #3 and how the architecture works,ACDRV will come before CMSRC.

[mcplslg123]

Re: LA-C501P No ACDRV??

I was replying base on post #3 and how the architecture works,ACDRV will come before CMSRC.

We all know the theory part.

[Udemzy]

Re: LA-C501P No ACDRV??

We all know the theory part.

We are both here to help.

[mcplslg123]

Re: LA-C501P No ACDRV??

We are both here to help.

Agreed friend

[dspok]

Re: LA-C501P No ACDRV??

If PQB1 doesn't switch,how then will CMSRC generate? To switch the MOSFET then ACDRV must be generated.

The practical way to generate ACDRV.

Check the impedance of the ACFET and RBFET( on diode mode,it should be above 0.400)
ACN and ACP communication with CLR(very important)
Impedance of CMSRC
Impedance of CLR
Impedance of REGN,ACDET,ACOK

Voltage on VCC,ACDET,REGN and ACOK

Thanks for reply, both ACFET and RBFET is +0.500 on diode mode source to drain only. Didn't understand CLR but ACN and ACP continuity is ok.
VCC=19v
ACDET=2.6v
REGN=6.0v
ACOK is missing.

Plz note: I fixed hp machine where ACFET wasn't ok, fixed with replacement. Now same issue on NM-B241.

[mcplslg123]

Re: LA-C501P No ACDRV??

SDA/SCL present?? What is the voltage on ILIM?? DK1-voltage on both sides?? Try removing DK1 and see if ACOK appears on charging IC.

[Sephir0th]

Re: LA-C501P No ACDRV??

ACOK will be pulled up from +3VL in this case so it can't be up if the LDO isn't working.

Imho best bet is to replace the charging IC right now

[dspok]

Re: LA-C501P No ACDRV??

ACOK will be pulled up from +3VL in this case so it can't be up if the LDO isn't working.

Imho best bet is to replace the charging IC right now

I already changed charging IC still PQ311 isn't switching. There is 0v on gate.
schematic attached.

[mon2]

Re: LA-C501P No ACDRV??

See attached.

1) Charger IC is a typical TI (BQ series) IC and is driving n-channel mosfets.

2) Carefully, with the power adapter connected - measure the voltage of:

pin # 4 = ACDRV (PU301)

This is the same voltage that is used to ENABLE / DISABLE the DCin mosfets.

3) Confirm that the resistor @ PR310 is present. With the power OFF -> confirm this resistor is ~4k ohms and that it does indeed mate with the mosfets.

4) Carefully, measure the voltage on each pin of PU301.

Do you have a voltage @ REGN ? (pin # 24)

This pin should be ~6 volts if all is well with PU301.

Post each measurement.

[Udemzy]

Re: LA-C501P No ACDRV??

Thanks for reply, both ACFET and RBFET is +0.500 on diode mode source to drain only. Didn't understand CLR but ACN and ACP continuity is ok.
VCC=19v
ACDET=2.6v
REGN=6.0v
ACOK is missing.

Plz note: I fixed hp machine where ACFET wasn't ok, fixed with replacement. Now same issue on NM-B241.

Check CLR communication with ACN and ACP with continuity, check impedance of CMSRC and impedance of ACOk.

This is all you need to release ACOk and when ACOk is available then ACDRV will come and by the way the IC you replace it with,is it good? Are you 100 percent sure about it?

[Sephir0th]

Re: LA-C501P No ACDRV??

Also in my opinion I can only think of colder solder joints around at charging controller and surrounding components left. Of course missing or failed resistor possible too.

Especially because we don't have seen any pictures about your work and the area in question so far.

[dspok]

Re: LA-C501P No ACDRV??

See attached.

1) Charger IC is a typical TI (BQ series) IC and is driving n-channel mosfets.

Yes it is.

2) Carefully, with the power adapter connected - measure the voltage of:

pin # 4 = ACDRV (PU301)

This is the same voltage that is used to ENABLE / DISABLE the DCin mosfets.

0.00v

3) Confirm that the resistor @ PR310 is present. With the power OFF -> confirm this resistor is ~4k ohms and that it does indeed mate with the mosfets.

Confirmed, and yes it is 4kohms.

4) Carefully, measure the voltage on each pin of PU301.

Do you have a voltage @ REGN ? (pin # 24)

This pin should be ~6 volts if all is well with PU301.

Yes it has 6.0v

Post each measurement.

Pin1: 0v
Pin2:0v
Pin3:0.0v
Pin4:0.0v
Pin5:0.0v
Pin6:2.71v
Pin7:0.0v
Pin8:0.0v
Pin9:0.0v
Pin10:0.0v
Pin11:0.0v
Pin12:.00v
Pin13:0.18v
Pin14:0.16v
Pin15:0.0v
Pin16:0.0v
Pin17:0.13v
Pin18:0.13v
Pin19:0.13v
Pin20:0.13v
Pin21:0.0v
Pin22:0.0v
Pin23:0.0v
Pin24:5.99v
Pin25:5.66v
Pin26:0.13v
Pin27:0.13v
Pin28:19v

[dspok]

Re: LA-C501P No ACDRV??

Also in my opinion I can only think of colder solder joints around at charging controller and surrounding components left. Of course missing or failed resistor possible too.

Especially because we don't have seen any pictures about your work and the area in question so far.

Here are the pictures the are I have worked so far.

[mon2]

Re: LA-C501P No ACDRV??

Pin20:0.13v

From the voltage on pin # 20 (VCC), the charger IC @ PUB01 is not being powered.

See attached.

Review the parts that have been highlighted.

The dual diode and series resistor must be present and working to allow for the raw ~19v to reach this charger IC to power up this logic board.

On a normal logic board, pin #20 should be ~19 volts. Confirm it and update this thread.

Start with the voltage check on each pin of PDB1 (dual diode). Pin #1 should be about the same as the adapter voltage.