Hi all, Would someone out there be able to tell me where I can get replacement servos for an old cinestar gimbal. both roll & roll motors are fried. Ive tried to replace the roll with a Savox digital servo which almost works but nowhere near as well as the originals. Thanks in advance. Marc
Hi Marcosss, welcome to the forum. If it's not too much trouble, would you be kind enough to change your user name to your real first name and last name, please? The reasons for this (and how to do it) are explained here: http://forum.freeflysystems.com/index.php?threads/real-names.497/ Regarding the Savox servos, what problems are you having? Provided you have the resistor installed, they should work -- I have a faint memory that FF's servos were from Savox, but I could be wrong. Thanks Andy ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Hi Andy Thanks for the reply & advice re name change. The Savox servo is a SC-1256TG, it is not a continuous rotation model, so it will only do a 100 degree movement, it also only has one lead coming out of it, so no room for a resistor. Like I said it does work but not effectively. I'm looking for a replacement unit that is the off the self equivalent to the original. Any clue on that? Thanks again Marc
Thanks, Marc (for the name change). I checked my "last surviving Radian Gimbal" and there is no clue on the Savox servos what the model number is, I'm afraid. I suspect you may have to drop an email to support@freeflysystems.com and see if either (a) they still have a few in a dusty box in the back, or (b) they can tell you which model of Savox it is. Sorry I can't be of more help. Andy ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Afterthought; I did a search for "Savox" on the forum and I think this is the model number: SAVOX SC-1258TG See http://forum.freeflysystems.com/index.php?threads/wanted-freefly-f360-0866-servos.6922/#post-63607 Andy ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Thank you so much for your time & help Andy. I'll have a look at the link. With some luck this will be the gold I'm looking for. M.
Hi Andy, had a look at the spec for the Savox SC-1258TG & it is not a 360 unfortunately. I'll try to chat with the guy who mentioned it & see if he made mods to it. So close & yet no cuppy doll. Dimensions(mm): 40.3x20.2x37.2 Weight(g): 52.4 Speed(@4.8V sec/60): .10 Torque(@4.8V oz-in): 133.3 Speed(@6.0V sec/60): .08 Torque(@6.0V oz-in): 166.6 Gear: Titanium & Aluminum Bearing: 2BB Case: Aluminum Running current (at no load): 100 mA @ 4.8V Running current (at no load): 120 mA @ 6.0V Stall current (at locked): 4000 mA @ 4.8V Stall current (at locked): 5000 mA @ 6.0V Idle current (at stopped): 5 mA @ 4.8V Idle current (at stopped): 5 mA @ 6.0V Limit angle: 200°±10° Connector wire gauge: #22 AWG Connector wire length: 250 ±5 mm Horn gear spline: 25T Control system: Pulse width modification Amplifier type: Digital Controller Operating Travel: 100° (when1000→2000 μsec) Neutral position: 1500 μsec Dead band width: 3 μsec Rotating direction: Counterclockwise (when1500→2000 μsec) Pulse width range: 800→2200 μsec Maximum travel: Approx 130°(when900→2100 μsec)
I think there's an internal potentiometer that is used to feed back the current rotational position of the servo. I suspect that FF disconnects that and replaces it with a resistor bridge that makes the servo "think" that it's always centered (faint memory, I measured the resistor pack that comes with the servos, and there are two 5.6K resistors with a center tap to the middle pin of the JR connector on the pack). Do a Google search for: modifying a servo for continuous rotation There are lots of results and that might allow you to take any suitable servo and make it spin forever! Andy ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Thanks again Andy, I've already looked at the 360 degree mod for the Savox, a labor intensive operation, but its doable, just need to get me some workshop space....haha! May take a few weeks at this rate, but I'll let you know how I go. Also found that the Radian was originally designed by Carvec & they have an interface called G-lock, sounds awesome until you come to the cost of 300 pound sterling for the update. Have you come across any hacks for the radian?
I'm afraid not, Marc. The Radian is somewhat "last year's technology" and the industry has moved on to using brushless motors because they're so much smoother in operation and have less mechanical play in them than the servos with belt drives. Andy. ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Yeah I hear you Andy, I was gifted a cinestar due to broken servos I'd say. A lovely piece of kit, just to nice to scrap. Maybe I'll convert it to a brushless using an Alexmoss board.....
I tried that route, but I found that I was incessantly having to tweak the Alexmos controller parameters -- to the point that it felt like I was spending more time tweaking than doing anything else! Sorry to rain your your parade! Andy ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Not raining on my parade at all Andy, I'll take it as good advice & go down the road of modding the servos. I've asked the guy who mentioned the Savox servo in the thread you pointed me to for any clues or advice on modding the servos. Thanks again. M
Hi Andy Just to let you know, I carried out the mod on the Savox servo, works almost perfectly. For some reason it will not accept the 30 & -30 degree travel limits, so if the gimbal moves any more than that the belt jumps, not that it will happen. Anyhow just wanted to thank you for your help once again. Marc
That's odd. If the pulley is loosened on the shaft, the servo should spin the pulley indefinitely. Is the belt damaged, I wonder? Or is something out of alignment? Andy ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Alignment is good, belt tension is good. it seems to be an issue with the radian not stopping the servo at the 30 deg + or - position. If it happens quickly the gimbals roll arm slams against the stop & the belt will jump a tooth. Seems odd that the radian is not sending a stop signal at the desired end limits. Current setting. Roll 1 default
Anyone you needs replacement servos look here. http://mymobilemms.com/OFFTHEGRIDWA...C-0252MG-SC-1258TG-Metal-Gear-Servo?cPath=18&
Good find, Marc. Andy ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert