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Feb 11, 2009, 08:46 AM
Team Wack-a-Mole
Melnic's Avatar
Discussion

HXT900 vs. Tower Pro 9g vs. Mystery 9g


I'm starting this thread to compare the Hextronix HXT900 sold by HobbyCity to the Tower Pro 9g servo and the Mystery 9g servo because there has been talk that these 3 servos are the same.
HXT900's are only available (that I saw) from HobbyCity
Tower Pro servos are everywhere.
Mystery servos are sold by dealextreme as well as on ebay and other places.

I will start off by saying that I purchased the Mystery and Tower Pro servos in the spring of 2008. The HXT900's were purchased in the early fall of 2008. So if the HXT900's had a production change, that might explain some differences.

I happened to have some of each. I have no scientific tests to compare the 3 servos but I will add that I have used all 3 to some extent. The Tower Pro servos are only in small electric airplanes and the HXT900's are in 2 of my EXI 450 helicopters. I also have HXT500's on all 4 of my servos in my Gaui EP100.

The first things I noticed is the case of the Mystery Servo is not even close to the Tower Pro and HXT900 cases. The coloring of the translucent case of the Myster is marketly different than the other 2. The Tower Pro and HXT are identical cases as the best that I can determine (except the label of course). Taking it apart, the coloring and mold markings of the Tower Pro and HXT are identical. The servo arms of the Mystery DO NOT fit on the tower pro or HXT. The case design of the Myster is different and no parts of the case of the Mystery is interchangable w/ the HXT or Tower Pro.The HXT and Tower Pro arms are interchangable. The gears of the HXT and Tower pro are interchangable and I could not notice a difference between the two.

Electronics:
It was the Electronics of the HXT and Tower pro where I noticed the difference. As you can see in the photos, the circuit board and controller chip of the Mystery, HXT and Tower Pro are totally different in size. It is not apparent by the photo but the HXT controller chip is narrower than the TP (that does not mean they are not the same though, just maybe a different chip package size. Both chips had the chip numbers on them scraped off.

Motors:
The motors are slightly different between the HXT and TP. One has the shaft of the bearing exposed, the other is covered. The case clamping on the motors are different as well which makes me think they are likely different motors. They may perform the same, but look different. The Mystery motor was shorter and had a plastic motor pinion.

Pots:
As you can see by the photos, the POTs are different. I don't think it makes much of a difference but the TP pot was 3K across and the HXT as well as Mystery pot was 3.5K across. The copper rivits in the HXT just seems to breath of quality to me. Mystery also has the same copper rivots as the HXT and the wiper looks the same but the plastic case of it is slightly different on the back.

Stickers:
Not shown are the NEARLY identical QC stickers on the HXT and TP servos. On the inside, however, the Tower Pro servos says "Tower Pro" with a mfg month/date on them. The HXT servo just has the mfg mont/date on them and the ext (QC Passed). The Tower Pro servo was dated 11/09 (funny, am I back to the future? or do the numbers mean something else?) and the HXT was dated 5/08.

BTW, I had one Mystery brand servo that never made it to a heli. It would "bounce" when returning to center. I did my test w/ a 3 position switched channel on a spare Rx I had. Switching to another Mystery 9g it did not do this.

Aircraft I have these brand of servos in:

Mystery 9g : GWS Slow Stick
Tower Pro : Sapac 330L Electric foamie (replaced the original junk servos that were chatty)
HXT900 : Blueray/EXI MA450 with Scale fuse Cyclic and Tail w/ Futaba GY240 gyro
HXT900 : EXI 450 Squadron Cyclic only
HXT900 : Esky HBK2 cyclic and tail w/ Esky 704A gyro
HXT500 : Gaui EP100 (originally had Mystery 3.7g servos but were not strong enough) on cyclic and tail w/ Imax Gyro
Last edited by Melnic; Feb 11, 2009 at 12:29 PM.
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Feb 11, 2009, 08:57 AM
Heli Humbled Daily
$5 each today:

http://www.xheli.com/topromisesg9.html

Lets hope they are worth something, I am getting 4 for an EXI450
Feb 11, 2009, 09:08 AM
anarchist
frac's Avatar
is it possible the difference in the TP and HXT is due to different production runs...different raw material? would they do that?

did you get a good look at the pots?

I want to see the equivalence issue settled



frac
Feb 11, 2009, 09:18 AM
Registered User
dude_109's Avatar
Melnic,
Thanks for the doing the physical comparison!!! I've always read in different places that they are different but now you've proved it so what I've read is not entirely hearsay after all. Being that my reading might not be hear say, I've also read that HXTs are more reliable than TowerPro. Testing to failure would be much more difficult. One would have to consider...material of the gear, quality of motor, quality of circuitry, etc...

I've only used HXT900s bought in August 2008. I've gotten ~50 flights in CopterX450 and ~15 flight in MiniTitan. Cyclic on both. One very very light tip over in grass with CopterX and HXTs were fine.
Feb 11, 2009, 09:22 AM
anarchist
frac's Avatar
melnic, can you improvise some sort of max force test?


frac
Feb 11, 2009, 09:28 AM
Registered User
There is not enough of sampling. Almost all manufacturers have more than one (single) source of materials as long as they meet specs.
Feb 11, 2009, 09:40 AM
Team Wack-a-Mole
Melnic's Avatar
OK, I just ripped them apart and sacrificed the 2 servos for the sake of knowledge....
At least I have spare gearsets out of them

Pictures and original post just updated to show motor and POTs.


Quote:
melnic, can you improvise some sort of max force test?
frac
I have a force gauge at work I might be able to use. I've always wanted to also create some sort of speed test also.

Quote:
There is not enough of sampling. Almost all manufacturers have more than one (single) source of materials as long as they meet specs.
Agree, I'd like to see if anyone has these to at least look at their circuit board from underneith. It is pretty easy to tell the difference between the two as the 3 servo wires come together on the TP circuit board and the HXT, they are spread out. Also the shape of the circuit board is different enough that you should be able to see it on yours. HXT has the U shape on one end and the TP is totally rectangular. Please anyone post differences in their servos if you have some older/newer than mine.

BUT, since there are differences in EACH of the 3 main components inside the guts, that would lead me to believe that they either change each production run or they are just different.
Feb 11, 2009, 09:54 AM
anarchist
frac's Avatar
Quote:
Originally Posted by Telemachus
$5 each today:

http://www.xheli.com/topromisesg9.html

Lets hope they are worth something, I am getting 4 for an EXI450
FYI hobbycity has the hxt900s available from a US warehouse for 4.99
and they ship via priority mail. these we know are good. but exploring is fun

don't forget the gearsets......xheli probably doesn't sell those


frac
Feb 11, 2009, 10:00 AM
LaurenceGough's Avatar
This is a case of spend a little more upfront save a lot later on.

I got two Tower Pro (HXT) SG90's which have failed after just a few flights on cyclic at 4.8V... (No binding, very easy to move all control surfaces, sport 400 size) PCB problem. Cheap and weak gears too.

HS-65MG's, 700+ flights no problem.
Feb 11, 2009, 10:15 AM
Registered User
MrRetro's Avatar
What do you guys feel about the statement on the HobbyKing site about these servos:

Quote:
These servos can be found on eBay and other asian sellers at close to this price, however be warned, they do not contain Taiwan/Japan components. HexTronik (the manufacturers of these servos) have two standards, one is for local sale, and the other is export quality with imported connectors and resin gears from Taiwan and Japan.
Our HXT500 and HXT900 are export only, and not built for the domestic market.
Feb 11, 2009, 10:22 AM
anarchist
frac's Avatar
Quote:
Originally Posted by Technex
This is a case of spend a little more upfront save a lot later on.
.
Technex we understand that there are good servos at a price.stop beating that horse.However there are some who have issues even with the 65s.

we're trying to find things that are quality at a good/better price, and in some cases we have done so.

why do you consistently refuse to comprehend this????

perhaps you would descend from the clouds and test these for us:

http://www.hobbycity.com/hobbycity/s...idProduct=8303



frac
(controlling fist of death....)
Last edited by frac; Feb 11, 2009 at 10:31 AM.
Feb 11, 2009, 10:24 AM
anarchist
frac's Avatar
Quote:
Originally Posted by MrRetro
What do you guys feel about the statement on the HobbyKing site about these servos:
one further point, HC IS hextronic

i dunno why they would short change their domestic market, that's just weird

frac
Feb 11, 2009, 10:37 AM
MasterBlaster runs Bartertown
Well, <you know who> is on the ignore list now. His constant low-level trolling (or incredibly bloated self importance, can't tell which) is getting old. You guys be sure to argue with him to help build his pathetic self esteem.
Last edited by eaterofdog; Feb 11, 2009 at 11:06 AM.
Feb 11, 2009, 10:44 AM
Team Wack-a-Mole
Melnic's Avatar
Stating you have had Tower Pro servos fail is useful information to me and the thread. I want to take samples of people's experiance as well as any info on differentiating the two servos to determine if they are the same or not.
Stating that the Tower Pro is an HXT is a matter of conjecture. If you don't have both and can't show they are the same, don't make the statement based on guessing.

HS-65MG may be better servos, I'm a Hyperion fan myself but that is not what this thread is all about.
Take pics of your Failed tower Pros' if you have them and you want to contribute.

thx.

Quote:
Originally Posted by Technex
This is a case of spend a little more upfront save a lot later on.

I got two Tower Pro (HXT) SG90's which have failed after just a few flights on cyclic at 4.8V... (No binding, very easy to move all control surfaces, sport 400 size) PCB problem. Cheap and weak gears too.

HS-65MG's, 700+ flights no problem.
Feb 11, 2009, 11:06 AM
BeeZaur 480
BowerR64's Avatar
Why wasnt there more images of the mystery?

i have all 3 of these servos thinking they were all the same but just rebadged.

I would also like to see these compaired to the HS55 hitech servo, ive wondered if they wernt clones of that servo that they want $13. for.


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