Using LM2596 DC-DC for N900
 

BL-5J is dead.
Converted a 19V charger to 4.0V using LM2596, attached to + and -. Added a 4.7K resistor between + and the third terminal.

Now, the phone is in boot-loop - repeatedly Nokia logo keeps on showing.


Any ideas?

Re: Using LM2596 DC-DC for N900
 

EDIT: Now it is not a bootloop. Nokia shows up as seen in the image. and then dies again.

Re: Using LM2596 DC-DC for N900
 

Buy a new battery?

Re: Using LM2596 DC-DC for N900
 

I would suggest the same before doing/trying anything else.

Re: Using LM2596 DC-DC for N900
 

I am not getting good batteries locally. Also, my use-case makes it compulsory to be plugged-in all the time. Last battery ended up getting the bulge in a month. Hence.

Re: Using LM2596 DC-DC for N900
 

As far as I know you need this small chip from an old battery.
So use the connector and small PCB from an old battery remove the battery and solder your voltage supply to it.

Re: Using LM2596 DC-DC for N900
 

For a full battery there is roughly 100kOhm between minus and third pin. This is measured by BME through twl4030-madc.
When the resistance is to low the watchdog kicks in. So remove the resistance between plus and third pin and try to solder a bigger one between minus and and third pin. At least 80kOhm.

Re: Using LM2596 DC-DC for N900
 

Yes this is what I did - use ~110K Ohms.

Found it here: https://electronics.stackexchange.co...some-batteries

&& ChatGpt (~100K Ohm)