I might be looking at this wrong but if the resistors on your ESC are the same as mine that little transistor "T7" will never turn on because R20 which is in series is 100k (+ the resistance of R7, R8 or R9) and R19 which is a pull down immediatley after is 10k
Ah yes, sorry for not being clear enough earlier. I seem to have all of the same silkscreen markings (component names) over here. For which resistors, capacitor etc.
But the value of R20 i measure is not same as yours (
not 100k):
R19 = 8.9k
R20 = 25.1k
R7 = 8.9k
I do not believe the other 2 hall sensors, R8 and R9 matters for A1. Because they do not connect to R20. Instead they connect to +5v (pulled up HIGH), which is for the bldc controller IC only.
But those are similar:
R8 = 9.7k
R9 = 9.7k
So maybe that can help you to get yours working.
I think they messed this up in the design.
Yes, or it could maybe be a component error in manufacture. My board is dated:
BST-2019.4.23. Perhaps the issue was specific to earlier models only. Or to a bad batch.
Did you try do disconnect A1 only and check if the blower works that way?
Thanks for explaining this part. What i did was to moved the A1 pin to GND, on next header. Because it seems active LOW (pull up otherwise).
* The blower does not work, however I did see some PWM signal squished. This means it's almost 0v. But you can still see a very small increase (few mV) bumps, when the PWM is high.
* So I think that is my next area to focus on.
What I have also done is to rule out the blower bldc FAN itself. This is not anything about the handle. This is only the FAN:
* Removed the fan housing and inspected the fan blades
* They are all fine. So the fan did not explode
* Checked all 3 motor coils - all coils are about 12 ohm. They connect circular in a loop to each other
* Checked all 3 hall sensors [HA HB HC], (for shaft position) all the position sensors are working
The hall sensors inside the motor become active during rotation. And the closed magnet reads about 12 ohm (same value as the coil resistance). And off is high impedence.
* Problem is somewhere else on esc board
* I cleaned the board with IPA, to remove tin whiskers
* Found they did put some white paint between the MOSFET legs
* It looks just like the other silkscreen, white lines. However it not!
* It is an extra layer of paint after above the silkscreen
They did on the top side the mosfets. But not on the bottom side, where the motor connector is. They missed that
My next focus is to look for why the PWM signal is killed, and drained to almost nothing. That is not normal operation, is it?
So maybe there is a bad (shorted) capacitor? Or other active component like small transistor? Maybe that is worth to investigate