HS-65MG Rebuild Instructions

[Dr. Memory]

Originally Posted by giskard

Thanks :o)

Now I just have to find a file small enough to open the screwholes a little!

Hmmm... I mount a drillbit of the appropriate size in the handle of a hex wrench (mine have removable shafts that are held in with a setscrew) and then auger the hole out manually.

Works really really well. I use this technique to enlarge all manner of small holes for my heli hobby as needed. This technique is especially good for up-sizing servo arm holes.

[offroader]

Originally Posted by trickybit

did you make sure the potentiometer is engaged properly?

How can I check that the potentiometer is engaged properly, not sure what to check?

[trickybit]

in the instructions, you'll see that you should center the shaft before you put on the gear with the little tab which engages it.

just re-read this forum carefully, and see if you had noticed all the steps.

[matchless]

This week, I got metal gear sets to replace the Karb. sets that came in my 65hb's. I rebuilt the servo like I would any other (I've been flying for 30yrs and replaced a lot of gearsets). When I tighten the case screws, the servo will not operate and feels bound when I try to turn the gears using the servo arm as a lever...(not something I normally do). I've also verified that there are no teeth left in the case from the previous stripped Karb. gearset.

If I loosen the case screws significantly, the servo operates as normal. If I remove the bearing from the output shaft and reinstall the case, the servo operates as normal. That tells me the bearing is binding.

I have checked that the gears are all meshing correctly, pressed into place correctly and seated in the case. Unfortunately, the servos simply won't operate with the metal gearset and the case properly installed.........

Any ideas or suggestions? Do I have the set installed wrong?

[carlyle]

After a crash this summer with my 450SE, I took out all three gear sets on the head using plastic gears in my HS65's. I ended up just replacing the servos with brand new 65MG's, but did get myself some new metal gears to repair my old servos.

After reviewing the videos, I just changed the gears on all three servos just as described. One servo works perfectly, another servo works, but not very well, and another servo hardly works at all.

Interesting enough, with the case off, all three servos work perfectly, but it is putting the top case on that is draging them down.

Any ideas on what could cause this?

[carlyle]

after taking a closer look at the servos, I found that the bearing wasn't totally seated on one of the servos. I was able to press it down tight, which helped quite a bit, however, I am still not totally happy with the performance of the servo. It just seems that the motor is working too hard for a no load application.

One servo is perfect, but the other two seems to be draggy.

[matchless]

Carlyle, I ended up making a hybrid geartrain to get mine to work. I have the metal output shaft, along with carbonite 1-2-3 gears. It works, but I'd still rather have the correct full set in my heli.

[carlyle]

seems to me we are doing something wrong. It must be possible to get these servos to run totally properly using the metal gears. I am going to continue working on mine and try and figure out what exactly is wrong. I agree that it must be something to do with the case causing the servo to bind.

[matchless]

My experience with them tells me the stack height of one of the gear stacks is too tall.... that is then binding with the case and keeping the whole thing from running......

[Mac_Heli]

My elevator 65MG had way more slop than the other servos, and after taking is apart I noticed that the problem was the bearing, plus is was really notchy. Looks like the repair kit doesn't include the bearing... is there a replacement for it? Anyone else had this issue?

[mfremont]

Originally Posted by Shef

So the other day, I stripped the Pitch and Aileron servos and replaced with MGs (finally). My elevator is still Karbonite...is there a reason to switch them out now too in order to keep everything consistent, or does it not matter?

Thanks.

I'm in the reverse situation. Stripped the karbonite gears in the elevator servo, but pitch and aileron are OK.

Same question. Should I take the time to upgrade the other two servos now? If I don't will it make a difference in how the heli flies?

[rdlohr]

OK, I uploaded all the pictures to helifreak so they shouldn't disappear anymore.
Rick

[Crash549]

uh posted by mistake.

[reaaz]

Hi, had 2 crashes this year with my trex, on both occations, HS65MG servo's never stripped. seemed to work perfectly. However after rebuild, testflights showed that the heli would lose alot of power after maybe 30-40 seconds in the air. kept on doing this, even after trying many different batteries, motors, speed controllers & even receivers.
Thus, I checked back the servo's & found 1 of the 3 servo's to be slightly stiff in movement, assumed gears were damaged, replaced gear set, even though original gear set looked perfect.
Test flew again, same thing is happening.
What do you think is happening here?? seems something is drawing so much current from the speed controller, that just maybe it is going into some kind of failsafe & lowering output to the motor.
could the problem lie within the HS65mg servo's ?? warped cases maybe?? should I try replacing gear set for the other two? It is definitely not a mechanical problem for sure.

[terry05]

hi bro ,,, i am terry from malaysia
i saw the video about hitec sevor repair
i have a futaba s9257 i change my gears but now it is making some noise bezz
y thats happening ? pls email me or do u have a video for that
thanks
terry

[Starcruiser]

check and see if the servo horn was pulled out a bit, I had this issue when I used a screw that was too long which pulled the horn up a mm which caused binding. use a pair of pliers to gently re-seat the horn.

[Halfdevil333]

Here is my drawing of servo gears , the numbers show the fitting order in which each gears. hope this makes sense.

https://www.helifreak.com/album.php?...ictureid=43201

[trickybit]

Originally Posted by Halfdevil333

Here is my drawing of servo gears , the numbers show the fitting order in which each gears. hope this makes sense.

https://www.helifreak.com/album.php?...ictureid=43201

Nice diagram.

It doesn't show clearly which gear is which, but I think the rule is that the 3 similar gears are installed in increasing order of the height of the inner gear portion. Stubbier hub area goes on first.

[HeliShredder]

Ok, I followed the instructions on the to rebuild a HS-65MG after a gear had stripped in a crash. After putting the heli back together while leveling the swash plate I noticed that the rebuilt servo moves slightly slower than the other cyclic servos, i.e., when going from full negative pitch to full positive pitch, the servo lags slightly behind (but the swash is level everywhere, after the slower servo catches up).

I don't know what the issue could be other that I somehow messed up the rebuild (the servo arms are all perfectly level at zero pitch, links same length etc.). Has anyone an idea what could be causing this problem and how to fix it?

Thanks!

EDIT: I found the problem: It seems like I forgot to put grease on the shafts before putting on the gears. I took the servo apart again and greased the shafts and it works fine now. While greasing the shafts is quite obvious, looking back at the instructions on the first page it doesn't say anything about that. Maybe someone could add it?

[walkera4g3]

I just bought 4 of these! I hope they're good?