Servo help please!! Hobbico CS170

[seph606]

Can anyone provide troubleshooting steps to isolate the torque or power loss in my Hobbico CS170? This servo is on my Enroute Berg Rock Crawler 2.2, with hot bodies tires (lead wheel weights), CKRC OTA steering kit w/knuckles.

Servo: Hobbico CS170

Issues:
1.) reduced torque/power
a.) On a flat smooth surface, such as a hard wood floor, the servo will move the tie-rod with enough torque to move the hard bodies tires with lead weights on the rim. During this test, there is no forward or reverse movement. The berg rock crawler is in the stopped position. The same test on a level grass surface will produce a slight whining noise from the servo and the servo does not have enough torque or power to move the tie rod or the tires. The tires will only move slightly (1/4") in the grass. The same problem occurs on rock surfaces. The berg will turn on grass or rock surfaces when the berg rock crawler is in movement. My steering is the CKRC over the axal (OTA) steering kit with high steering knuckles. I am using an aluminum servo horn (the servo horn was cut too short, or shorter than the average servo horn, or definitely less than 1"), and I recently replaced the plastic internal gear with a metal replacement gear (i stripped the plastic gear during rock crawling practice).

Questions:
1.) Are there setting in the radio that can reduce the servo power or torque?
a.) I may have unintentionally made adjustments to the servo power via the radio while adjusting the turn radius.
2.) Can a shorter than average servo horn cause the appearance of a loss of power or torque during turns or binds?
b.) The servo horn was originally cut a little bit to short to clear the tie rod in front of the axal. Since that time I have upgraded to over the axal steering (OTA) and I now have more than sufficient room for a longer servo horn, but I am still running the super short servo horn. The short servo horn is causing a smaller turning radius, however, it is still enough of a turn not to notice unless you are looking for it (wheels just barely clears the shocks, about 1/8").

Please help me trouble shoot this issue before I send in for repairs. Thanks for your help with this issue.

[Scattman]

You need an external bec would be my bet.

We need more info though. (batts, esc, rec, etc)

[SMR 510RR]

And a pic of how short your horn is.

Leverage increases force for a given torque so yes a short horn could cause this problem. Torque is the measurement or rotational strength not linear force.

And yes, you should run a BEC to power the servo.

[jkwrangler08]

x2 on the BEC..

But, I also have the CKRC BTA steering and if it's not setup just right, it will bind up on you.. The binding I had was mostly trying to come from a full throw left or right.. It would bind up and stick.. I have made little bushings similar to what's on steering knuckles that are slightly thicker than the CKRC material where the screws go through to the knuckles. This insures that that screws don't tighten themselves up as you turn left and right and there is no tension.
to test, loosen the screws at the knuckle to see if it moves better..

Also needed to insure that the rod from the servo arm to the steering are is as straight as possible.. Mine originally had a downward angle to it.. Added some spacers and all is good.

The shorter servo arm will actually give you "more" torque than a longer one..

[oldhippie]

Originally Posted by seph606

Can anyone provide troubleshooting steps to isolate the torque or power loss in my Hobbico CS170? This servo is on my Enroute Berg Rock Crawler 2.2, with hot bodies tires (lead wheel weights), CKRC OTA steering kit w/knuckles.

Servo: Hobbico CS170

Issues:
1.) reduced torque/power
a.) On a flat smooth surface, such as a hard wood floor, the servo will move the tie-rod with enough torque to move the hard bodies tires with lead weights on the rim. During this test, there is no forward or reverse movement. The berg rock crawler is in the stopped position. The same test on a level grass surface will produce a slight whining noise from the servo and the servo does not have enough torque or power to move the tie rod or the tires. The tires will only move slightly (1/4") in the grass. The same problem occurs on rock surfaces. The berg will turn on grass or rock surfaces when the berg rock crawler is in movement. My steering is the CKRC over the axal (OTA) steering kit with high steering knuckles. I am using an aluminum servo horn (the servo horn was cut too short, or shorter than the average servo horn, or definitely less than 1"), and I recently replaced the plastic internal gear with a metal replacement gear (i stripped the plastic gear during rock crawling practice).

The c-170 should easily turn the wheels on any surface!

Questions:
1.) Are there setting in the radio that can reduce the servo power or torque?

I don't know of any radio adjustment that would effect servo torque/power. Only center and end positions plus expo that will change the rate/speed the servo moves in it throw.

a.) I may have unintentionally made adjustments to the servo power via the radio while adjusting the turn radius.
2.) Can a shorter than average servo horn cause the appearance of a loss of power or torque during turns or binds?

A shorter servo horn will provide more torque (but the servo will need to move farther) than a longer horn.

b.) The servo horn was originally cut a little bit to short to clear the tie rod in front of the axal. Since that time I have upgraded to over the axal steering (OTA) and I now have more than sufficient room for a longer servo horn, but I am still running the super short servo horn. The short servo horn is causing a smaller turning radius, however, it is still enough of a turn not to notice unless you are looking for it (wheels just barely clears the shocks, about 1/8").

Please help me trouble shoot this issue before I send in for repairs. Thanks for your help with this issue.

My experience is Hobbico (and hitec) servos tend to lose torque/power over time/use? I would really check for binding in the linkage/knuckles/axles. Everything should move very freely with the servo disconnected. I don't know about Hobbico repair service?