acer aspire nitro an515-54 missing 3v

[dqtech]

i have an acer nitro 5 with problem no power....ive check on 19v and 5v is normal reading...only missing 3v...here i attach boardview and schematic

[mon2]

Re: acer aspire nitro an515-54 missing 3v

Which 3v is missing ? Each is based on a local EN (enable pin) -> measure the voltage to ground of these EN pins.

Also, with no power -> meter in resistance mode -> check the resistance to ground of the 3VALWP and also the LDO rail for 3V.

If the resistance is low, the local regulator may be shutting down. Low resistance could mean a shorted cap downstream or some other high current event.

For now, do not consider voltage injection - which must be kept low @ 1 volt or under. This is just in case the CPU rail is shorted to this rail so we do not want to inject a higher voltage.

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

Which 3v is missing ? Each is based on a local EN (enable pin) -> measure the voltage to ground of these EN pins.

Also, with no power -> meter in resistance mode -> check the resistance to ground of the 3VALWP and also the LDO rail for 3V.

If the resistance is low, the local regulator may be shutting down. Low resistance could mean a shorted cap downstream or some other high current event.

For now, do not consider voltage injection - which must be kept low @ 1 volt or under. This is just in case the CPU rail is shorted to this rail so we do not want to inject a higher voltage.

no 3v on PL301....EN1 (pin 12) read 3.3v and EN2 (pin 11) read 4.35v....ive check resistance on PL301, 3VALWP and LDO reading 0.5v and no short

[mon2]

Re: acer aspire nitro an515-54 missing 3v

19V is reaching the IN pins on PU301 ?

What is the resistance to ground of the LDO and 3VALWP ?

If the readings are not low, then PU301 is defective and should be replaced.

When shopping for a replacement (recommend Hong Ming on Aliexpress - they have been good for our past purchases) - be sure to share the full part #. Often the suffix of the part number will define the enable pin logic levels, etc.

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

19V is reaching the IN pins on PU301 ?

What is the resistance to ground of the LDO and 3VALWP ?

If the readings are not low, then PU301 is defective and should be replaced.

When shopping for a replacement (recommend Hong Ming on Aliexpress - they have been good for our past purchases) - be sure to share the full part #. Often the suffix of the part number will define the enable pin logic levels, etc.

yes 19v reach on PU301....reading resistance on LDO and 3VALWP not low...ill try to replace PU301 first

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

19V is reaching the IN pins on PU301 ?

What is the resistance to ground of the LDO and 3VALWP ?

If the readings are not low, then PU301 is defective and should be replaced.

When shopping for a replacement (recommend Hong Ming on Aliexpress - they have been good for our past purchases) - be sure to share the full part #. Often the suffix of the part number will define the enable pin logic levels, etc.

update....i already replace PU301 with new ic but also not work...3valwp not present

[mon2]

Re: acer aspire nitro an515-54 missing 3v

See attached.

Post your voltage reading to ground after the short / solder blob is removed.

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

See attached.

Post your voltage reading to ground after the short / solder blob is removed.

no reading on +3VALWP (pin 1) sir

[mon2]

Re: acer aspire nitro an515-54 missing 3v

1) is the replacement part a known good part?

2) same part number as the original?

3) what is the voltage to ground of the LDO rail on this regulator?

4) confirm the soldering with lots of flux, enough hot air and air pressure to make this part swim and naturally rest onto the pads. When the solder is in liquid state, gently push the IC at the corners and the IC will push away and return back onto the pads. This process will fix any potential solder shorts. Then allow it to cool and test again.

5) if the parts on this regulator circuit are not missing, the voltage should be present if the solder blob is removed. That is, a no load should allow for the proper voltage output.

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

1) is the replacement part a known good part?

2) same part number as the original?

3) what is the voltage to ground of the LDO rail on this regulator?

4) confirm the soldering with lots of flux, enough hot air and air pressure to make this part swim and naturally rest onto the pads. When the solder is in liquid state, gently push the IC at the corners and the IC will push away and return back onto the pads. This process will fix any potential solder shorts. Then allow it to cool and test again.

5) if the parts on this regulator circuit are not missing, the voltage should be present if the solder blob is removed. That is, a no load should allow for the proper voltage output.

1) yes, new ic

2) yes same with original part

3) LDO on pin 17 got 3.3v

4) yes everything good

[mon2]

Re: acer aspire nitro an515-54 missing 3v

Check the resistance of the parts and reflow these parts at the output stage of this regulator that link with PL301.

Compare the resistance values against the schematic values.

The LDO working is a good start. The switching regulator leg of the regulator should be on as well.

With no power, measure the resistance to ground again of PL301. What is the reading?

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

Check the resistance of the parts and reflow these parts at the output stage of this regulator that link with PL301.

Compare the resistance values against the schematic values.

The LDO working is a good start. The switching regulator leg of the regulator should be on as well.

With no power, measure the resistance to ground again of PL301. What is the reading?

PL301 resistance read 0.348v sir

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

reading on all part that link with PL301 is normal...accept PR305 that should be 100k but only read 89k...is that okay?

[mon2]

Re: acer aspire nitro an515-54 missing 3v

PL301 resistance read 0.348v

Can you double check this? Resistance checks will be with no power, meter in resistance mode.

One meter probe on PL301, other meter probe to ground.

Resistance will be in ohms. If you read '1' or 'OL', then the meter scale is too low. Select the next higher scale on the meter till you have a reading.

After the above, meter in DC volts mode (10 volts or higher). Then check the voltage to ground of PL301.

What is the measurement?

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

Can you double check this? Resistance checks will be with no power, meter in resistance mode.

One meter probe on PL301, other meter probe to ground.

Resistance will be in ohms. If you read '1' or 'OL', then the meter scale is too low. Select the next higher scale on the meter till you have a reading.

After the above, meter in DC volts mode (10 volts or higher). Then check the voltage to ground of PL301.

What is the measurement?

am i right?



i only have this multimeter

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

in DC volts mode, no voltage reading at all on PL301

[mon2]

Re: acer aspire nitro an515-54 missing 3v

The meter has 3 functions in the yellow setting.

You are currently in DIODE mode. Press the yellow button till you see the greek symbol OMEGA for the resistance scale.

Then take your measurement again.

[dqtech]

Re: acer aspire nitro an515-54 missing 3v

The meter has 3 functions in the yellow setting.

You are currently in DIODE mode. Press the yellow button till you see the greek symbol OMEGA for the resistance scale.

Then take your measurement again.

sorry my bad...this one?

[mon2]

Re: acer aspire nitro an515-54 missing 3v

Good reading at 8k34 ohms. That is not a short. The regulator should be on. Will review the details of this regulator deeper after the soccer game. Fairly sure it is active high enable which you have.

Post close up pics of this regulator and parts. Any burnt looking parts in this region?

[mon2]

Re: acer aspire nitro an515-54 missing 3v

Wow. Quite the game.

Remove all power. Meter in resistance mode. Check the resistance across the PL301 contacts.

What is the measurement?