RCCrawler Forums

AC-130 · 07-24-2009, 11:36 AM

So I'm having issues with my DIG servo. It seems to have about 1/8" slop in it coming from the horn when powered up which allows my dig to fall out into free wheel. I am running a HiTec HS 645 MG Servo. I have been told this is normal but there has to be a way to set my epa's and/or trim to fix this. I have an HR dig and am running a DX3R Tx. I am really new to the hobby so if anyone can help me with the proper setup, any advice would be appreciated.

Thanks!

clockworks · 07-24-2009, 12:26 PM

If you can move the horn easily with your finger when the servo is powered, either the horn is loose/damaged (wrong fitting for the servo, damaged splines or not seated correctly) or the servo is damaged - stripped gears or faulty potentiometer.

Hitec servos use a different fitting to just about every other maker. Same diameter, but different number of splines - are you sure it's got the correct number of splines (24)?

The 645 is a moderately powerful servo and you shouldn't be able to move it easily. Are you sure that the slop is at the servo horn, not in the rest of the linkage?

EPA or trim won't fix a loose servo. EPA is End Point Adjustment - how far the servo moves when the Tx stick, wheel or switch is moved end to end. Trim is where the servo sits when the Tx stick, wheel or switch is at neutral.
You might be able to compensate for slop by increasing the EPA, but it'll probably get worse.

AC-130 · 07-24-2009, 01:01 PM

Thanks! I'll try to shorten the linkage and I'll check the splines. Although, my steering servo does the same thing and I was told they all do that.

Nate08 · 07-24-2009, 01:08 PM

Not sure who told you they all do that, but I've yet to have slop in a servo that wasn't related to either a stripped horn or stripped gears in the servo itself.

clockworks · 07-24-2009, 01:43 PM

x2
Only the very cheapest no-name servos have slop. Quality units like the 645 certainly don't.

Scottmisfits · 07-25-2009, 02:31 PM

After you've checked the horn, see if it's the servo itself. If it is the servo, take the top off. You'll see a series of gears. Mark them with a sharpie, all on the same side, such as put a little mark towards the top. Take all the gears out and turn them 180*. This in essense, gives you a new set of gears to work with. All servo's, over time, will develop slop, whether they are metal or plastic gear servo's. You can also get replacement gear sets for most servo's. With a 645, by the time you've flipped the gears and it wears out again, buy a new servo. Everything else is close to being done as well. And for a $30 servo and a $10-15 gear set, it's not worth it to replace the gears.

07-24-2009, 11:36 AM	#1
AC-130 Newbie Join Date: Jun 2009 Location: Vacaville Posts: 32	Sloppy Servo So I'm having issues with my DIG servo. It seems to have about 1/8" slop in it coming from the horn when powered up which allows my dig to fall out into free wheel. I am running a HiTec HS 645 MG Servo. I have been told this is normal but there has to be a way to set my epa's and/or trim to fix this. I have an HR dig and am running a DX3R Tx. I am really new to the hobby so if anyone can help me with the proper setup, any advice would be appreciated. Thanks!

07-24-2009, 12:26 PM	#2
clockworks Rock Crawler Join Date: Feb 2008 Location: UK Posts: 818	If you can move the horn easily with your finger when the servo is powered, either the horn is loose/damaged (wrong fitting for the servo, damaged splines or not seated correctly) or the servo is damaged - stripped gears or faulty potentiometer. Hitec servos use a different fitting to just about every other maker. Same diameter, but different number of splines - are you sure it's got the correct number of splines (24)? The 645 is a moderately powerful servo and you shouldn't be able to move it easily. Are you sure that the slop is at the servo horn, not in the rest of the linkage? EPA or trim won't fix a loose servo. EPA is End Point Adjustment - how far the servo moves when the Tx stick, wheel or switch is moved end to end. Trim is where the servo sits when the Tx stick, wheel or switch is at neutral. You might be able to compensate for slop by increasing the EPA, but it'll probably get worse. Last edited by clockworks; 07-24-2009 at 12:30 PM.

07-24-2009, 01:01 PM	#3
AC-130 Newbie Join Date: Jun 2009 Location: Vacaville Posts: 32	Thanks! I'll try to shorten the linkage and I'll check the splines. Although, my steering servo does the same thing and I was told they all do that.

07-24-2009, 01:08 PM	#4
Nate08 Rock Crawler Join Date: Jul 2008 Location: Port Angeles Posts: 656	Not sure who told you they all do that, but I've yet to have slop in a servo that wasn't related to either a stripped horn or stripped gears in the servo itself.

07-24-2009, 01:43 PM	#5
clockworks Rock Crawler Join Date: Feb 2008 Location: UK Posts: 818	x2 Only the very cheapest no-name servos have slop. Quality units like the 645 certainly don't.

07-25-2009, 02:31 PM	#6
Scottmisfits Rock Crawler Join Date: Apr 2008 Location: Calgary Posts: 913	After you've checked the horn, see if it's the servo itself. If it is the servo, take the top off. You'll see a series of gears. Mark them with a sharpie, all on the same side, such as put a little mark towards the top. Take all the gears out and turn them 180*. This in essense, gives you a new set of gears to work with. All servo's, over time, will develop slop, whether they are metal or plastic gear servo's. You can also get replacement gear sets for most servo's. With a 645, by the time you've flipped the gears and it wears out again, buy a new servo. Everything else is close to being done as well. And for a $30 servo and a $10-15 gear set, it's not worth it to replace the gears.

Sponsored Links

RCCrawler Forums

Thread: Sloppy Servo