New to the forums and I require your help regarding a problem I’m encountering.
I recently acquired a CCPM servo consistency tester and I tried it out on two MG996R servos but something isn’t going right. Instead of being able to switch modes on the servo tester all three LEDs just light up and blink and the servos just run odd. In pulses. I know it’s not supposed to behave this way. I should be able to select the modes to test the servo.
My guess is one of two things: They are digital servos so the tester is having issues with them or it’s the way I’m powering the tester.
The setup consist of:
Soderless breadboard
YW Robot breadboard power supply 5V max output
CCPM Servo consistency tester
Mg996r servo
6v power supply
Am I doing this right or do I need to power the servo tester directly and not use any type of power board/bridge?
The max power output of the board is 5v.
The minimum/maximum power needed to run the servo is 4.8v/6v.
I’m not familiar with this servo tester or power supply, but power supplies in general require a minimum input voltage to provide the rated output.
You don’t state what kind of “6v power supply” you are using. That’s important.
But, if this is the YW breadboard supply you are using, notice what it says:
Product Specifications:
Locking On/Off Switch
LED Power Indicator Input voltage: 6.5-12v (DC) via 5.5mm x 2.1mm plug
Output voltage: 3.3V/5v
Maximum output current: 700 mA
Independent control rail output. 0v, 3.3v, 5v to breadboard
Output header pins for convenient external use
Size: 2.1 in x 1.4 in
USB device connector onboard for power output to external device
You also have to consider the current capability of the “6v power supply” as well as the breadboard supply, and how much current the servo tester AND the servos need. A max of 700 mA (from the breadboard supply) is really pushing it with two servos, not even counting the tester.
I suspect if you use a better supply your problems will go away.
You are right. I should have explained the power adaptor a little better. It is a AC power adaptor.
I have also used a 9v battery connector with a barrel jack on the breadboard power board and got the same result.
To eliminate the breadboard I’ve also used a Multi Output Voltage Conversion DC-DC 12V to 3.3V 5V 12V Step Down Power Supply Module:
One input: DC 6V - 12V (input voltage to the output voltage must be higher than 1V.)
Output: 3.3V (+ - 0.05v error), 5.0V (+ - 0.05v error), 800mA (load current can not exceed 800ma),
12V (12V input directly converter to the output)
PCB board size: 4.5cm * 4.5cm
Even with a 9v battery attached to this type of board I’ve gotten the same result.
Maybe I should bypass power boards all together when using the tester?
Full sized servos typically take a couple hundred milliamps to operate, minimum. A 9V battery is lucky to provide 200 mA on a good day (try it. Set a multimeter on 10 Amp current range and connect directly across the 9V battery.)
The servos need 4.8V to 6V. Four AA batteries can provide that. I don’t know what voltage the servo tester needs. But it probably needs to be fairly “clean” (i.e. without noise and other stuff, just smooth DC.) I would power the servos from four fresh AA batteries and if that voltage is suitable for the tester, use it for that also. If the tester can take the (up to 6.5V) voltage of the AAs, there’s no need for any voltage regulator, power converter, power supply, whatever. AA alkaline or NiMH can provide plenty of current.
The servo tester needs 4.8v-6v to operate. I believe you are correct though. I will acquire a 4 AA battery holder or something akin to that for the servo testers needs and just run it without boards.
I didn’t think the breadboard or the power supply module would interfere with the current so much as to cause a problem with a simple tester.
You’re welcome. Hope it helps.
In situations like that I would estimate something like 80 to 90% of the problems are power related.
If that doesn’t fix the problem let us know and we’ll go from there.
Good luck!
Well I used a 4 AA battery holder and behold, it worked just fine. Now I’m just dissapointed my servos turn about 120° instead of 180°. They are full metal gears though and I imagine that they are designed more for torque than anything. (MG996R)
The original servo “specs” (there weren’t really any, it just became most common) was for 90 degrees. So you could consider anything beyond that as “extra” Not very many will do a full 180. In my experience about 120 to 150 is common.
glad you got it working!
