Ferm One electric screwdriver has no power

[Antti]

Re: Ferm One electric screwdriver has no power

put a meter across the battery and tell us the voltage both normally and when the charger is plugged in.

btw, does the motor run if you connect it to something else?

Ok, it was only 3.64 volts, i charged it and waited about 5 mins, and it was still 3.64 volts... weird because last time I checked it, volts were higher and it started almost right away charge the battery.

[stj]

Re: Ferm One electric screwdriver has no power

so what voltage did you see with the charger PLUGGED IN. ??
i asked that for a reason - i wanted to know if it was trying to charge.

[Antti]

Re: Ferm One electric screwdriver has no power

it was still 3.64 volts when the charger was plugged in.

Greenlight was flashing like it does when its charging.... but it didnt charge...

[stj]

Re: Ferm One electric screwdriver has no power

then we are progressing.

[Antti]

Re: Ferm One electric screwdriver has no power

I just tested the motor, soldered the battery and motor off and connected them together, motor started rolling, so atleast motor is working

[stj]

Re: Ferm One electric screwdriver has no power

so it's around the charge/battery controller.

[kc8adu]

Re: Ferm One electric screwdriver has no power

replace the tp4056.
its not charging and the battery is below low voltage disconnect.or is the instant you pull the trigger.

[Antti]

Re: Ferm One electric screwdriver has no power

Ok, Is it hard to solder? its a very small piece...

[kc8adu]

Re: Ferm One electric screwdriver has no power

need hot air.heatsink pad under chip.

[stj]

Re: Ferm One electric screwdriver has no power

not so sure, in the foto it looks like they used thermal paste / glue instead of solder.
interesting method, i may try using it myself next time.

[fzabkar]

Re: Ferm One electric screwdriver has no power

Check the output voltage of the charging IC. It should be 4.20V. If this voltage is present, but the battery voltage is 3.64V, then I would think that either M1 or M2 is not being switched on. ISTM that one is involved in charging, the other in driving the motor. The smaller chip probably controls the charging/operating modes.