A2159 no power test (no charger)

[marce002]

Re: A2159 no power test (no charger)

Yes mon , 12,26V if fuse is removed , with just 5v from my usb cable standard, although 12,26 seems to be a little low right? seems to be 0,007A draw

[marce002]

Re: A2159 no power test (no charger)

yes I confirm, with just 5v usb standard cable, it is 12,26V at fuse (removed) , and just 0,007A draw

[marce002]

Re: A2159 no power test (no charger)

with fuse soldered back, 0,3v at fuse, and just 0,012A draw

[marce002]

Re: A2159 no power test (no charger)

U4910 is the one that gets hot when 5v is injected at F7000 with fuse ..and 300mah draw.. u4910 seems to be 3.0V MESA.. i have removed it and now seems to be no more short ...of course it does not mean it is the culprit but just to let you know where we are. thnks

[mon2]

Re: A2159 no power test (no charger)

After removing the parts that are heating up...what us the new resistance to ground with F7000 removed?

Since you do see ~12v before the fuse, this confirms that the isl9240 is working as a boost regulator.

However, the load is too much on this line so the voltage drops. Leave the fuse off for now...do not bypass or bridge it. We need to find the part causing this low resistance. Those parts may need to be replaced. AliExpress is the usual go-to place.

[marce002]

Re: A2159 no power test (no charger)

no something got wrong now RES is 11ohm to gnd from removed load part.... put back the IC u4910 and it is also 11ohm... so i should have not energized the board without that u4910 removed maybe.... it still has 12,26v in the other side of fuse... so sad

[piernov]

Re: A2159 no power test (no charger)

If injecting voltage on a power rail causes a part not connected to it to heat up it should give a clue as to what to look for… and definitely confirm that continuing to inject voltage is a bad idea.
Also never a good to work on a board worth a few hundred bucks and potentially holding data without even having the correct power supply for it and basic tools.

[marce002]

Re: A2159 no power test (no charger)

yes yes absolutely, i will put this on pause until i have the proper tools... will keep this updated. thanks to all.