Hello guys.
I am IT guy, but from time to time, I try to learn new things.
The problem is that in our company we have some ATM with shutter, like in banks.
The shutter does not fully open, but close normally, because it use springs to close.
This pcb has also 2 position sensor to identify the position of shutter, open or closed.
I did try to feed 12V motor with external power, 12V and 9V, shutter opens and close without problem.
In my opinion, pcb feed motor with pulse voltage, and if the voltage time is low, motor does not have enought time to close the shutter.
Please check my pcb if you can identify any component which use this method.
Thank you all.
I see a 1ohm resistor.
That could be a sense resistor for motor current.
The shutters might have some safety mechanism.
If the motor draws too much current while opening/closing (e.g. hand under shutter), the motor stops.
Are you sure the shutters move freely (no excessive friction).
Leo..
U2 appears to be an ATMEL microcontroller, and I would expect that it would be handling any timed events on your circuit board.
Can't tell what S1 is, but wonder if it gets hot when the motor is operating? Checking that might help you confirm Wawa's thought regarding that 1Ohm resistor.
All just guess work though on my part.
Thank you gentelman for your reply.
S1 is a button to operate manually the shutter, ie. without data cable.
I cannot find where is the 1 oh resistor. Can you tell me, so i can try to check it
Chip is Atmel, seems like model tiny26 dmu1234, but cannot read it for sure.
I'm uploading 3 photos, 1 is shutter in closed position, 2 in closed position.
When shutter is closed, I use S1 button to operate, and shutter try to reach opened position, but goes only till middle of operation. If I try with hand to open the leveler, motor goes till open position. Looks like it is because motor does not have power to open it, but when I feed motor with 12V or even 9V, it has enough power to open the shutter. So I think that shutter operate with pulse voltage, let's say 1/2 sec draw on. If this time is lower, motor does not get enough power. This is just e theory.
1R0
But I didn't tell you to check the resistor (which looks fine).
I asked if the shutters move freely.
Is that paint near the C4 printing, or did someone cut the circuit board trace there (going to 1R0).
Leo..
The shutter does not move freely, cause there is distancator, but even the working shutter does not move freely. C4 is not cut, it is just a dust. In total, I have 7 PCB with the same problem.
I'm trying to upload a video of normal operation and from shutter with problem in youtube. I will post the link here.
Working shutter:
Broken shutter:
Is the position sensor working properly? Does the motor work well till half way, or just stagger to that position?
Can you put a scope across the motor to see what volts it's getting?
Allan
Position sensor work well. I block manually sensor A and B, and led stay green. Looks like the motor does not have enough force, but I did try with external voltage, 12 and 9V and shutter opens and close without problem.
Cannot meassure voltage, cause output voltage to motor, does not stay on for long time. Meaning as soon as metal part reach bottom place, draw should be cut from PCB, since it has reached sensor position.
In the video with broken shutter, when I help shutter door with hand, motor goes to open position.
Maybe the motor draws too much for the current sensor. Try adding another 1 ohm resistor in parallel with the big 1R0 resistor on the circuit board.
Allan
Output voltage from PCB to motor is 12V for both, working and non working PCB. This is strange, cause when i connect working PCB with motor from shutter which is not working, shutter opens and close without problem. Also I connect in reverse motor from working shutter with non working PCB, and it does not work.
So problem is with board, but cannot understand why.
I will try also to add a second 1R0 to see the difference.