Anonymous at Fri, 29 Mar 2024 16:15:06 UTC No. 16103333

>>16103330
might be Q4 base current protection.

Anonymous at Fri, 29 Mar 2024 16:19:41 UTC No. 16103336

>>16103333
huh? i though it would have to do with droping voltage

Anonymous at Fri, 29 Mar 2024 16:24:57 UTC No. 16103342

it biases the transistor that supplies charging current to the batteries when there is a charging voltage detected. biasing the transistor just means turning it on so that the amplified current runs perpendicular along the collector-emitter. Build the circuit online and see what happens
https://www.falstad.com/circuit/

Anonymous at Fri, 29 Mar 2024 16:32:03 UTC No. 16103355

>>16103342
>amplified current runs perpendicular along the collector-emitter.
I get what you mean but don't say perpendicular lmao

Anonymous at Fri, 29 Mar 2024 16:50:26 UTC No. 16103367

>>16103330
You can do this because there is a second 100 Ohm in series.

Anonymous at Fri, 29 Mar 2024 16:53:00 UTC No. 16103370

>>16103330
>what about replacing with a 220ohm resistor?
depends on charging current. increasing R31 will decrease the current through Q4 and Q9

Anonymous at Fri, 29 Mar 2024 17:05:28 UTC No. 16103385

>>16103342
so it just drops voltage not to open the transistor as fast? that was my guess

anyways i welded another 100 ohm resistor (actually two 230ohm resistors in paralel, but whatever) in that place but the charging still never ends for some reason. maybe i burned the charge control logic board when i shorted the transistor and resistor previously

Anonymous at Fri, 29 Mar 2024 17:13:59 UTC No. 16103393

>>16103385
>but the charging still never ends for some reason
huh? the IC senses if you connected power source, via pin 34, and turns on Q4. if the cells are Li-Ion they will charge at fixed current until they reach 4.2V, then current lowers. IC doesn't know the state of cells, see no sense line. what's the logic for turning Q4 off apart from disconnecting charge source?

Anonymous at Fri, 29 Mar 2024 17:55:39 UTC No. 16103466

>>16103393
how do you know it works like that? i think it checks cells' voltage somehow and stops when they reach 1,3V (NiCd batteries). anyways it doesnt ever cut now for some reason. i wonder if a burnt transistor would short or open. proabbly one is shorted

Anonymous at Fri, 29 Mar 2024 17:59:10 UTC No. 16103473

>>16103466
>somehow
yeah that's what I'm saying, based on what you posted there's no other sensing.

Anonymous at Fri, 29 Mar 2024 19:29:31 UTC No. 16103625

>>16103473
my point is how do you even know that bbic does what you said and not control voltage? im pretty sure it does the later bc the light turns on only when i plug it in

Anonymous at Fri, 29 Mar 2024 19:53:32 UTC No. 16103663

>>16103625
>im pretty sure it does the later bc the light turns on only when i plug it in
really bro

Anonymous at Fri, 29 Mar 2024 21:01:49 UTC No. 16103744

>>16103663
yeah, otherwise it wouldnt have done that when i shorted the transistor (and it still did). and when i opened the circuit it didnt even load. it definitely checks battery voltage
whatever i'm just gonna put some resistor in series with the batteries to protect from overvoltage

Anonymous at Fri, 29 Mar 2024 22:03:58 UTC No. 16103854

>>16103744
you can check with dmm on continuity between battery + terminal (without battery connected) and micro pins. might have a resistor in series, so maybe check resistance not continuity. if nothing comes up it might not be sensing the battery.
the led could be it with a resistor in series connected across battery. it would light up when you connect the battery. but maybe it does detect it somehow