Welcome to Synthiam!

The easiest way to program the most powerful robots. Use technologies by leading industry experts. ARC is a free-to-use robot programming software that makes servo automation, computer vision, autonomous navigation, and artificial intelligence easy.

Get Started
United Kingdom
Asked — Edited
Resolved Resolved by DJ Sures!

Right Shoulder Servo Burn Out

Hi just got my JD today and following build and cal tried a few sit up and stand moves, after several goes smoke from shoulder. Result is servo overheated and locked. Reading back I have seen comment on tight movement and did notice that both shoulders are a lot tighter that other joints. Have now asked shop in uk to send new servo but would like advise on shoulder joints to get my JD dancing again.


ARC Pro

Upgrade to ARC Pro

Your robot can be more than a simple automated machine with the power of ARC Pro!

PRO
Canada
#1  
Hello @kgreaves81, Send a warranty message on our Contact Us page and we'll get it sorted out!
United Kingdom
#2  
Hi Jeremie thx have sent message, should the shoulder joints be tighter than other joints to move by hand when doing cal. As they did seem tight but had nothing to gauge them too. Guess they should move freely by hand, is there any adjustment needed when doing cal on shoulder servo,s
Thx KG
PRO
Canada
#3  
We have seen tight shoulder joints on JD in the past. There's not much you can do in terms of calibration but @Aislinn should be able to fill you in on the rest of the details when she gets in tomorrow, thanks!
PRO
Synthiam
#4  
If they are tight, please ask for instructions on how to modify the shoulder holes to loosen the servos. If you do not modify the shoulder holes then the replacement servos will burn out again.
United Kingdom
#5  
Hi DJ please can give instructions to loosen shoulder joint as both were tighter than other joints during cal, and I don't want to loose another servo, also what controls location of servo position in body and is a bit of lube worth a try. Guys many thanks for the quick response, and do you have UK spares supplier . KG

just to update have removed body and checked free rotation of left servo by hand, it is significantly tighter when in the body with the retaining screw fully tightened. when removed from the body the servo moves freely. so will need to adjust fit for both servos to prevent further servo burn out of replacement right and left thanks

KG
United Kingdom
#6  
DJ
Just done a few checks on the fit of shoulder servo mounts.

Internal diameter of hole in body 13.12 /13.06mm

Diameter of servo mount is tapered an increases in size 13.06/ 13.43mm max with interference fit to body bore.
This results in the servo mount locking when tighten down by servo screw. To solve the issue you need to tighten the tolerance on the servo mount o/d. The scraping of the bore is only a repair but is not the root cause of your quality problem.
Hope this helps solve this going forward. In the mean time I need to get my JD up and running
Thx KG
PRO
Synthiam
#7  
That is correct. We have repaired the issue with the body in the injection mold process many months ago. The unit you have is from first generation of that mold.

There are thousands of JD's out there:) we found out about that issue immediately and resolved it. Sadly there is still original stock on shelves from some retailers.
United Kingdom
#8  
That's fine but the unlucky ones like me end up with a JD with no arms, can you get the spare parts in the post so I can get him built also it would be good to put a note in the build instructions to check the shoulder servos for tightness or locking during assembly
So far there is no way of getting spare parts in the UK that I know of
Thx KG
PRO
Synthiam
#9  
What spare parts are you looking for?

There are only a handful of JD's with the shoulder issue - we caught it quick. You're getting a free replacement shoulder servo, wouldn't say that's unlucky:) enjoy your JD!
PRO
Belgium
#10  
i had same problem ,its an easy fix.i ordered some spare servo's just incase.
now i dont have to wait.i fixed mine whit a new metal drill from 14 mm
looks and sounds drastic,but you see nothing from using the drill.
i drill them by hand whit glove on.also i did bolt just incase.
not many or all first molded has this issue,i seen only about 3 inclu myself.
i bin here almost a year i think.
United Kingdom
#11  
Look forward to new servo and will refit with free movement , will see JD dance again.
Login to post a comment