Dell Inspiron 14 7437 no power, need schematics

[sellit]

Got Dell Inspiron 14 7437 with no power, didn't find any shorts. Got 19V on input, 9V after power mosfets. No power on 3.3V, 5V, RAM and CPU chokes. No shorts on chokes. Got 3.2V on Power button.
Need schematics please.

[mcplslg123]

Re: Dell Inspiron 14 7437 no power, need schematics

try cmos reset

[BlueMidnight]

Re: Dell Inspiron 14 7437 no power, need schematics

Compare the attached schematic to your board to see if it's the right one. The input MOSFETs in the schematic are PU4201 (page 42) and PU4405 (page 44).

[sellit]

Re: Dell Inspiron 14 7437 no power, need schematics

Thanks BlueMidnight, it's correct schematics.
After input MOSFETs PU4201 PU4405 got correct voltage 19V.
But after charger MOSFETs PU4406 and PU4407 got 9V on DCBATOUT, is that voltage correct?
On 3V/5V controller PU4501 VCC got 9V. No voltage on PL4502 and PL4503.
Injecting 3V and 5V on PL4502 and PL4503 got laptop startup OK.
Can it be IC PU4501 fault, or ICs VCC is too low?

[sellit]

Re: Dell Inspiron 14 7437 no power, need schematics

Attached picture with voltages I get on PU4501.

[BlueMidnight]

Re: Dell Inspiron 14 7437 no power, need schematics

On this board, the BQ24715 (PU4404) doesn't just charge the battery. It also powers the main system rail (DCBATOUT). So the DC jack voltage stops there, and it uses the PU4406/PU4407 MOSFETs to create voltage on DCBATOUT. Anything from 9-20V is fine. And PU4501 can operate on anything from 5-24V.

The most likely bad components are PU4501 and/or PU4502 and/or PU4503. The first thing I would personally do is test PU4502 and PU4503. They are just 2 MOSFETs in one package and they should be testable just like separate MOSFETs would be.

I notice that PU4501 has latched PU4503 in the overvoltage protection configuration (with the upper FET turned off but the lower FET turned on with 5V on pin 11 of PU4501). That might mean there's something wrong with PU4503, but could just as easily mean PU4501 is bad, etc.

[sellit]

Re: Dell Inspiron 14 7437 no power, need schematics

Thanks for help. Purchased PU4501, will give an update after replacement.

[sellit]

Re: Dell Inspiron 14 7437 no power, need schematics

Replaced PU4501, made no difference. Purchased PU4502 and PU4503.

[sellit]

Re: Dell Inspiron 14 7437 no power, need schematics

Replaced PU4502 and PU4503, no difference. The same voltages. Can I inject on some pins voltage to make it work? Like PGood or DRVL1.

[mielta]

Re: Dell Inspiron 14 7437 no power, need schematics

Hi
You must check Pgood Pin7 it must be 3.3v it goes to Side 17 from the schematic
Q1701

[alig]

Re: Dell Inspiron 14 7437 no power, need schematics

Did you fix this

[ronelex]

Re: Dell Inspiron 14 7437 no power, need schematics

try replace the filter capacitor on the 5v and 3v line

[rediii]

Re: Dell Inspiron 14 7437 no power, need schematics

try replace the filter capacitor on the 5v and 3v line

that would have been my suggest, too. it fixed two of these machines already.

[AG Electronics]

Re: Dell Inspiron 14 7437 no power, need schematics

I can confirm that if all conditions above met. Replacing capacitors in 3V/5V lines resolves no power on laptop.

[hirens]

Re: Dell Inspiron 14 7437 no power, need schematics

need bios bin file for dell inspiron 14-7437

[mon2]

Re: Dell Inspiron 14 7437 no power, need schematics

@hirens, bios requests are in a different part of this forum. See above. Can you repost your request there?