Big Help need with 9252 problem

[nightstalker]

Hi All

I have just got my hands on 3 9252 servos there brand new,
now i have then installed in my airskipper 50 on a ccpm set up,
now when i mover the Ailerons they judder, there not smooth and crisp,

so what i did next was unplug all servos and just connect 1 9252 in to the throttle servo and its perfect smooth and fast, so i tried all 3 and yep all fine,

So next i installed 1 servo in to channel 1, then 2, then 6 and it still kept juddering,

so i changed my swashplate types to standard eg: like raptor, just channel 6 for pitch and again pucker nice and smooth and crisp

does any one have any ideas what i can check?????

i had on there before hi-tech HS6635s and they was smooth and i retried them and still are,

TX is FUTABA 7CHP
BATT is 3600 MAH 4.8V
FUTABE PCM RX


SO any hints of times would be so helpful right now as i want to fly tomorrow,


One thing il say is there servos are fine so i know it cant be them as they work great on any other channel





What i have tried so far:
i have removed everything from the rx apart from 1 servo and the BATT lead i moved it from channel 1, 2 and 6 and it still juddered, i tried all 3 servos and still the same, i also tried it on the throttle channel and the tail channel and still the judder,

now made up another model as you said and reset it up and still it does the same,

next i changed the swash plate type and hey they worked perfect but i cant us that swash type, so i know its not the servos,

the swash type i use when i get this judder is HR3 but it does not judder when up moving the pitch up and down only when move the aileron and elevator that its juddering


i wish i could do a video of it, but i tried it on my web cam and it dont pic it up,


Now when i had my old servos in HITECH HS6635s they was smooth with no problems

[jimbob]

Is the battery fully charged? Just a shot in the dark, but maybe all three servos are dropping the voltage too much cos the batteries flat?

Just an idea...

[nightstalker]

yep fully charged, i even juet left 1 servo plugger in and the batt nothing else and it still judders (not smooth)

[jimbob]

is it a PCM Rx?
When i once changed a heli to digi servos I had all sorts of problems like yours, until I changed the Rx to a PCM one - then it all was fine....
Perhaps you have a PCM Rx to try?

Oh sorry - I see it IS a PCM Rx - maybe try another one anyhow? Thats probably the next logical fault finding step...

[nightstalker]

Its a brand new Futaba R-149DP 9 Channel PCM Receiver, the other servos was also digi servos and there fine, i just dont get it

[Steve]

I have 2 x 9252s on my Millennium 90 cyclic with a JR PCM receiver and 3600 mAh battery pack. Always ben absolutely smooth as can be, no problems at all. Have never tried them with any other receiver or battery pack. Not much help to you I know, but they are damn fine servos none-the-less.

[jimbob]

Its really odd that the just changeing the servos makes a difference - Somethings obviously up.
Did you try setting up say a plane, and using the three servos as Aileron, Elevator and Rudder and seeing what happens?

[nightstalker]

I change the CRYSTALs and still the same i then tried a PPM rx and they work spot on, now i have another PCM RX and tried that and its back to the judders, it seems like 9252s dont like pcm

[jimbob]

Odd innit - I had similar to this as I said but I changed non digi Hi-techs to Digi ones - lots of buzzing untill I changed to a PCM Rx - maybe its a frame rate thing?

[nightstalker]

i dont have a clue now, as i cant run PPM at my club as its a rule and i kept getting glitches when i used ppm

[Ade_Law]

9252s are excellent servos. do you have a battery monitor you could hook up?

tried plugging the battery straight into the rx to eliminate the switch?

Ade

[nightstalker]

Well been beck to the shop i got the RX from, had it checked with another of the same RX and still the same, also while there we tried the same RX with 9C TX and they worked spot on,

so its come down to that futaba 7CHP gives a restriction to servos when using a pcm RX, i know this sounds silly but when we tried a PPM rx everything was super fast and smooth and crisp,

so now iv gone to D/C and this seems spot on now,

[Steve]

My 9252s are running on a synthesised JR SPCM - no problems.

[nightstalker]

Yeah seems fine with Any other radio but with the Futaba 7chp the pcm seems to slow the servos down, we had 2 TX the same one on pcm with the RX i had and one on PPM same servos and the PPM made the servo move faster smooth and crisp, but the pcm made it judder and slow not smooth at all,

Im not sure about jr radios but plug a servo in a jr PPM rx and see if there is a change in speed, i have installed my new RX and the ccpm is awesome really smooth and crisp cant wait to test it,
so i have ordered a fail safe for my throttle so i comply with club rules

[Steve]

You could try a Multiplex IPD receiver.

It's PPM with failsafe.