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-   -   Digital Servos from China (https://www.rctech.net/forum/radio-electronics/1003830-digital-servos-china.html)

frewster 03-02-2021 04:40 PM

I decided to compare the A86BHM, on the left, to the A80BHSW, on the right. The A80 is shorter, both in case size and motor length. The gears are almost identical although the A80BHSW servo spline gear does not have a pin to keep it from rotating 360 degrees. The A86BHM has a pin and a a slot that keeps it from rotating more than about 220 degrees. The encoder for the A86 cannot rotate continuously but the one for the A80 can, of course.

The A80BHSW has the encoder and the motor held in with the same white epoxy as in Bill's, so that's another difference from the A86BHM.

The board is identical to the A86BHM but, like on Bill's, the codes on the FETs has been removed so I can't identify them.

The biggest difference I noticed was the pin for the center gear. It's 2.0mm in diameter for the A86BHM and only 1.6mm for the A80BHSW.
https://cimg7.ibsrv.net/gimg/www.rct...a6497886b0.jpg
​​​​​​

billdelong 03-02-2021 05:53 PM

It's also worth noting that the FET's are considerably larger on the NitroPro servo as compared to the AGFrc servo.


So quick list of NitroPro upgrades that I'm aware of:


1) Upgraded FET's

2) Upgraded POT's

3) Upgraded circuit board and all the installed components

4) Redesigned case to prevent motor pinion gear from sliding off the shaft

5) Redesigned installation of the POT to prevent it from sliding out of place


Simply put, the pricing for the AGFrc branded servos is not worth what they are charging. spend the extra $40 to save you $80 of frustration, been there done that!


What's sad is that I considered selling the repaired servos, but I just can't in good faith pass forward these potential time bombs :(

Losiracer12 03-02-2021 09:55 PM


Originally Posted by frewster (Post 15759915)
I decided to compare the A86BHM, on the left, to the A80BHSW, on the right. The A80 is shorter, both in case size and motor length. The gears are almost identical although the A80BHSW servo spline gear does not have a pin to keep it from rotating 360 degrees. The A86BHM has a pin and a a slot that keeps it from rotating more than about 220 degrees. The encoder for the A86 cannot rotate continuously but the one for the A80 can, of course.

The A80BHSW has the encoder and the motor held in with the same white epoxy as in Bill's, so that's another difference from the A86BHM.

The board is identical to the A86BHM but, like on Bill's, the codes on the FETs has been removed so I can't identify them.

The biggest difference I noticed was the pin for the center gear. It's 2.0mm in diameter for the A86BHM and only 1.6mm for the A80BHSW.
https://cimg7.ibsrv.net/gimg/www.rct...a6497886b0.jpg
​​​​​​

is the board the same as Bill’s Nitro Pro?

the wrench 03-03-2021 01:42 AM


Originally Posted by billdelong (Post 15759888)
Do yourself a favor and take a Lexus for a test drive, then you will quickly understand the differences that I'm talking about:

https://www.lexusgwinnett.com/2019-l...yota-camry.htm





Lexus is 302 / 203 = 49% more powerful among a slough of other features, no less different than the improved quality that NitroPro offers above AGFrc branded servos.

Yeah, I've been able to address some of the defects with the 40KG servos, but I've got a 36K (AGFrc) servo that still can't provide any load after resetting the pinion on the servo motor :(

ill never lease a gloirfied corolla, or fall for emotional marketing Bill, if you need to justify your purchase than so be it, but nothing about a lexus is 50 percent more valuable than a corolla.... using the same drivetrain and unibody, so please with all due respect, i disagree yet again with this analogy, maybe agf revised the original boards and found a cheaper component set for their a81 series, none of us know if the board is improved or if its a further cost cut, not machining the motor gear boss saves time, it takes away a machining step... all i know is my servo isnt here and i think were just running in circles about quality vs cheap value chinese servos, if it lasts than its a good servo, thats all im concerned with when buying into a sub 100 dollar component, my only interest in these servos has been the ability to use SSR mode and see if it adds resolution to my mt4s for more steering "feel"

frewster 04-03-2021 05:03 PM

I raced for the first time since October last night.

I've still got the Blue Bird BLS-30A in my ebuggy. It's so quick and strong that I run it at 7.3V to tame it down a bit. Tons of crashes but it's still going strong and I took 3rd place in my main.

Still running a couple of AGF A80BHSW servos in my nitro buggy. Still no problems with them, either. Plenty strong and precise. Was able to take 3rd in my nitro main as well.

I'll try to remember to post updates when I race in order to find out how reliable these servos are.


frewster 04-12-2021 07:21 PM

Servo update:

Couldn't race my nitro buggy with the AGF servos this past Saturday - not enough people - but I did race my ebuggy with the Blue Bird and my etruggy with another A80BHSW for steering.

The truggy broke a steering link in a tumble during the first round of qualifying, and I wasn't able to make my main, but the servo is still working well.

I took 3rd in ebuggy after a lot of tumbles and crashes with no problems from the servo. The Blue Bird is still doing fine and is more than fast enough on the lower voltage I run it on.

billdelong 04-12-2021 08:59 PM

CT1 update:


After 17+ race days the pin in the CT1 eventually snapped... not really surprised because that's about the only thing that hasn't been upgraded yet. I spoke with NitroPro and they are testing softer (more flexible) pins that should handle a little flex and be less likely to snap.


https://live.staticflickr.com/65535/...a9987335_b.jpg



Although I could've sent the servo in for a free warranty replacement pin, I opted to make a quick repair myself and figured I would start my own testing by using a body clip which is the exact same 1.6mm diameter I need, and I believe these body clips are about as soft of a metal as I can get in this diameter :)


https://live.staticflickr.com/65535/...217c5257_b.jpg


I've got 4+ race days with the repaired servo installed in my recently built E8T evo3:

https://www.rcgroups.com/forums/show...0#post46791599


I have already bought an SRT 9032 servo to replace the CT1 when the pin snaps again... only question is will it go longer than 15 race days with the softer metal???


Good news is that a snapped pin has never caused a DNF, but I make it a point to check for a locked servo after every race just to be sure as the symptom for a snapped pin. If you continue to use the servo after the pin has snapped, then you risk bending the shaft of the servo motor which could make the servo un-repairable... been there, done that with an AGFrc servo already :(

frewster 04-12-2021 09:37 PM

Thanks for the update, Bill. If you're looking for something else (I know you just bought the SRT) I can't recommend the 2nd gen Blue Bird's highly enough. Just make sure it has soft start and stall protection like the BLS-30A does and you'll know it's one of the new ones. 1st gen had some issues but fortunately Flight Comp refunded me when mine failed.

Shawn B 04-13-2021 12:11 AM


Originally Posted by billdelong (Post 15775739)
CT1 update:


After 17+ race days the pin in the CT1 eventually snapped... not really surprised because that's about the only thing that hasn't been upgraded yet. I spoke with NitroPro and they are testing softer (more flexible) pins that should handle a little flex and be less likely to snap.


https://live.staticflickr.com/65535/...a9987335_b.jpg



Although I could've sent the servo in for a free warranty replacement pin, I opted to make a quick repair myself and figured I would start my own testing by using a body clip which is the exact same 1.6mm diameter I need, and I believe these body clips are about as soft of a metal as I can get in this diameter :)


https://live.staticflickr.com/65535/...217c5257_b.jpg


I've got 4+ race days with the servo installed in my recently built E8T evo3:

https://www.rcgroups.com/forums/show...0#post46791599


I have already bought an SRT 9032 servo to replace the CT1 when the pin snaps again... only question is will it go longer than 15 race days with the softer metal???


Good news is that a snapped pin has never caused a DNF, but I make it a point to check for a locked servo after every race just to be sure as the symptom for a snapped pin. If you continue to use the servo after the pin has snapped, then you risk bending the shaft of the servo motor which could make the servo un-repairable... been there, done that with an AGFrc servo already :(

So your Nitro Pro only lasted a couple of months until it broke. That’s still unsatisfactory in my opinion.

billdelong 04-13-2021 09:16 AM


Originally Posted by Shawn B (Post 15775771)
So your Nitro Pro only lasted a couple of months until it broke. That’s still unsatisfactory in my opinion.

+1
Key difference is that with NitroPro you get lifetime warranty on the servo gears, if you go with AGFrc, then it will cost you $33 after shipping to replace the pin yourself... or cut a body clip like I did for free ;)

What I'm more interested is testing the theory that a softer metal in the pin will make it last longer and if the body clip repair stands the test of time, then the CT1 could be one of the best servos on the market for the price.

HaulinBass 04-13-2021 10:17 AM

I dont get why every servo needs an aluminum top case nowadays, for crawlers that often break servo cases due to the way servos mount sure .
A 1/8th car especially nitro imo its a stupid from an engineering perspective unless your designing something too both cost more and fail more often. lots of vibration + flex on a ridged mounted component the force has to go somewhere.
Full aluminum top cases and titanium servo gears are two things that pretty much ensure your servo will have a buttload of slop in short order.
how long do you think the ring and pinion would survive in a 1/8th with aluminum bulkheads? Exact same concept.
Machining the top case from carbon fiber would be just as dumb and twice as expensive to the consumer look for the manufactures to try that next for the guy that needs that extra .00001s a lap for his damn 17.5t 2wd buggy.

Shawn B 04-13-2021 10:49 AM


Originally Posted by billdelong (Post 15775880)
+1
Key difference is that with NitroPro you get lifetime warranty on the servo gears, if you go with AGFrc, then it will cost you $33 after shipping to replace the pin yourself... or cut a body clip like I did for free ;)

What I'm more interested is testing the theory that a softer metal in the pin will make it last longer and if the body clip repair stands the test of time, then the CT1 could be one of the best servos on the market for the price.

But now you are spending more in the long run then if you were to just get a legit servo to begin with. Not to mention the lost treasure of a body clip that can never be found in the pit box when our heat is up and need one in a hurry lol

billdelong 04-13-2021 01:23 PM


Originally Posted by HaulinBass (Post 15775898)
I dont get why every servo needs an aluminum top case nowadays..

They are necessary if you use flat head screws to keep the servo centered on the mount holes like this:





Originally Posted by Shawn B (Post 15775913)
But now you are spending more in the long run then if you were to just get a legit servo to begin with. Not to mention the lost treasure of a body clip that can never be found in the pit box when our heat is up and need one in a hurry lol

Time will tell if the body clip mod will hold up better, I trust NitroPro will sort it out soon and fact remains that NitroPro stands behind their product with a solid warranty unlike AGFrc. So long term cost on NitroPro is nil, but yes... long term cost to maintain AGFrc is astronomical :(

Regardless, all servos fail over time, typically the gears eventually wear out and having a lifetime warranty on the gears from NitroPro is priceless. The warranty on the SRT servos that I recently bought are only 1 year.... there's always going to be a trade off somewhere.

themountain 04-14-2021 05:41 AM


Originally Posted by billdelong (Post 15775880)
What I'm more interested is testing the theory that a softer metal in the pin will make it last longer and if the body clip repair stands the test of time, then the CT1 could be one of the best servos on the market for the price.

https://www.vintagemodelcompany.com/...x-l-457mm.html
;):nod:

Shawn B 04-14-2021 09:22 AM


Originally Posted by billdelong (Post 15775971)
They are necessary if you use flat head screws to keep the servo centered on the mount holes like this:

https://www.youtube.com/watch?v=UnqcI0JkiUQ





Time will tell if the body clip mod will hold up better, I trust NitroPro will sort it out soon and fact remains that NitroPro stands behind their product with a solid warranty unlike AGFrc. So long term cost on NitroPro is nil, but yes... long term cost to maintain AGFrc is astronomical :(

Regardless, all servos fail over time, typically the gears eventually wear out and having a lifetime warranty on the gears from NitroPro is priceless. The warranty on the SRT servos that I recently bought are only 1 year.... there's always going to be a trade off somewhere.

but are the gears covered for normal wear? I believe that if they break then yes but normal wear and tear I don’t think that they will cover


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