I probably could go directly to EZ Robot with this question but I'm hoping someone here can answer this question simply and quickly.
I have an EZ Robot HD servo that will only rotate one way manually with the power off. With the power off I can easily and freely move it to the right. However it will not move back to the left. It's like there is a block in there. However, here's the weird part. If I power it up and command it to move through ARC it will center and move the full range of motion both ways just fine.
I think this started when the robot arm joint it's mounted in free spun with weight when handling it. The with the power off. Maybe the gears may have hit the end stop inside the servo?
I probably should replace the servo in the arm joint but I'm just curious why it wouldn't move in one direction by hand with power off but acts correctly and moves both ways when powered on. Any insight?
It sounds like you're experiencing an issue with the internal mechanics of the EZ-Robot HD servo. When servos are powered off, they typically can be moved manually in both directions with some resistance due to the gearing. However, if you're only able to move the servo in one direction manually, it could indicate a potential issue with the internal gears or a physical obstruction.
Given that the servo operates normally when powered on and controlled through ARC, the electronics and motor of the servo seem to be functioning correctly. The issue appears to be mechanical rather than electrical.
Here are a few possibilities for what might be happening:
Internal Stop: Some servos have an internal physical stop to prevent over-rotation. If the servo was forced past its normal range of motion, it's possible that part of the gear train is now resting against this stop when unpowered.
Gear Damage: If the servo was forced beyond its limits or experienced a sudden impact, there could be damage to the gears, such as stripped teeth or misalignment. This might not prevent powered operation but could cause issues when trying to move the servo by hand.
Mechanical Binding: There could be a mechanical bind within the gear train that is overcome by the motor's torque when powered but is noticeable when trying to move the servo manually.
Since the servo is still functioning when powered, it may not be necessary to replace it immediately, especially if it's not exhibiting any issues during normal operation. However, if the servo is part of a critical system where reliability is paramount, or if you start noticing performance issues, it would be wise to consider replacing it to avoid future problems.
For more information on servos and troubleshooting, you can refer to the EZ-Robot HD servo product page and documentation: https://synthiam.com/Support/Hardware/EZ-Robot-HD-Servo
If you decide to replace the servo or require further assistance, you can find the EZ-Robot HD servo and other components on the EZ-Robot website: https://synthiam.com/Shop/Products/HD-Servo
Remember to handle the servo and your robot's joints carefully to avoid stressing the mechanical components, especially when the power is off.
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hi dave
you still use the old HD servo ? i got new HDD that didn go less then 20 degree and not further then 150 degree . today it stops working complete . i also notest with the latest ARC servo script doesn work , at the first click of mouse button .
hi dave
found the problem . its a broken plastik tab . i took the plastiek out , still desame problem . i also notest the axel goes way further then normal .
jeremie is this warrenty ? this was a new one .
https://www.youtube.com/watch?v=YgnlyLHztf0&ab_channel=EDP
hi dave/jeremie
i notest somethin arkwart . am gessing this is done delibertly . a tiny hole from 1 MM straight towarts the motor . dave do you have this too? also the circuitboard and rubber on the wire looks , not done properly .
@Nomad, Actually all the servos I'm using from EZ Robot are the new HDD. I really love them. I'm sure what ever is stopping this one HDD servo from manually moving it back to the left is my fault. It probably broke the physical stop inside the servo when I let the joint drop. I can't easily open it as it's embedded in a tight place in the robot arm. However I'm going to pull it out in a few weeks and replace it. I'll open it up and inspect it then.
I've never seen a hole in any of my servos like you show above. That's weird. From the pic the hole doesn't look drilled. It's got an odd shape. it's almost like the hole melted open.
hi dave
i wil open the servo compleet see whats inside . but if it melted what cause that ?
hey dave
it looks like its an contineus rotation servo with the wrong circuitboard or firmwire on it . it spins only in one direction . as soon the middle gear is connected it blocks .
@Nomad, I can't say if the servo is damaged. However I think it is not a continuous servo. From memory, I think the physical stop is inside the top cover that you have removed and set aside. Didn't you show a bit of plastic resting on the gear set in one of your other videos? I think this peace of plastic it that stop that broke off. Also there is a pot inside the servo housing and under the big gear you are turning with your fingers. The motor may be spinning until the pot is turned to a point in the one direction. I see that happening when you turn the gear with your fingers. So it may be that the circuit board is good. Now, you say the servo wont turn the other direction? Perhaps the pot is bad?
I don't know what caused the melted hole. However just a guess; maybe the motor overheated because of the plastic broken stop jammed in the gear set and caused the hole to melt in the servo housing next to the motor?
Time for a new servo unless you have parts from an old servo to replace these damaged ones.