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[dpbarry]

Hi folks.

Just a query on Servos.

Are servos matched to particular Frequency modulation. i.e FM or AM.

I know this is a boating forum but since there are quite a lot of intellegent folk on the forum, I thought I'd post it here.

The servos and RX system I have is for a Monster Nitro truck (27Mhx), so I thought I remove them and replace it with a 40Meg setup.  I then discovered that the receiver I have (40Meg) wouldn't fit properly into the RX cradle. I left the S148 servos in the truck and plugged back in the 27Mhz RX but got no joy in getting the 27Mhz RX to work with the Futaba S148 servos.  I then though I had damaged the RX somehow so plugged it back into my Nitro car and lo and behold, it worked fine.

So, as above, are servos somehow matched to FM or AM.  All pinouts look the same on the Koyosho KS-3 servos (signal, red, black) as the futaba.  The 148 work fine on the 40meg RX but not with the 27Meg Rx.

Any ideas?

Declan

[Fast Electricals]

All servos are pretty much standard and can be used with any type of radio system. The only real difference is the servo plug which can vary between manufacturers. If the plug you are intending to use does not fit it can usually be adapted by trimming the plastic with a craft knife. If you do modify the plug, check it is inserted the same way round as the original manufacturers equipment. The plug will have 3 wires red, black and another colour. The red and black wires power the servo and the third wire carries the data telling the servo which way to go. Just make sure the same coloured wires are connected to the same pin as with the manufacturers original equipment.


Neil

[Fast Electricals]

I have found a couple of links that you may find useful:

http://www.servocity.com/html/connector_types.html

http://www.rccaraction.com/articles/ht_uprgradio3.asp


Neil

[dpbarry]

Doh!! What a plank I am  ::)

Connected the 27Mhz RX up again to the Nitro Racer car I have to ensure that the RX was indeed working okay.

Doh! i thought.. nothing happened.  Not even a switch on glitch. That's weird.  Changed the batteries and still nothing.

Bit of headscratching.  What have I done wrong?? So, connected to the S148 servos.  Same thing.  Right, has to be a logical explanation so started to do a bit of electrical tracing.  Still nothing..  Everything seemed fine.

Now, this is where I went wrong and need a good slap around the chops given that I also fly aircraft. I wasn't following proper procedure for switching on TX then RX.

I wasn't actually using the flippin TX at all as I was seated at my bench and expecting some sort of initial moment from the servos which I appied power to the RX but something at the back of my mind niggled at me about an article I had read on a HPI TX and RX on ebay.  It said that the RX had a failsafe which is a must for RC card and boats etc and I thought to myself, does this RX need to have the presence of a TX signal in initiate itself.

Guess what.  I connected the RX up to the original Koyosho servos and switched on the TX then the RX and everything started to work as it should.  Hells bells I thought, I wonder is that the same for the S148 servos. I repeated the same procedure for the S148 servos and hey presto, everthing worked.

Gawd.. What I D**k I feel.

Many thanks to all who replied to my query. 

Moral of story.  Don't buck procedure.. even if it is in your bedroom or garage!  :-[

Regards

Declan

[Doc]

Declan,
Everything to do with frequency/bands/AM/FM/etc stops at the receiver.  The receiver then converts the received signal to something that makes sense to the servos.  So, servos are interdenominational, if that makes sense?
 - 'Doc

PS - No, it doesn't make sense.  But, neither do I, so what.  I do have an excuse.  It's called coffee deprivation.  And that's just dumb enough to make sense.

[BobF]

Hi,

I once had the same problem (servos that is)

I always check gear before going to the pond, as I can't quite get the whole workshop in the back of my car.
On arriving, I turned on and nothing worked. I checked all connections and batteries but still nothing.
This was using a bec system and electronic speed control.
I swapped to a new receiver and also connected a new servo. Dead, so I replaced the ESP, still dead.

I finally spotted the problem had been caused by the servo reverse being knocked on the throttle side of the transmitter on the way to the pond, and it was exactly half way between settings. Once it had been set to the up position again, everything worked.? The ESP was not able to set as it was not getting a signal, so no power back to the receiver. So simple, but so hard to spot.
Bit like me really being thick and small.

Bob

[dpbarry]

Glad to see there are better mortal than me who can make mistakes.  As you say Bob, its the one's smacking you about the gob that appear to be the most difficult to get the brain to register on. 

Declan

[cbr900]

Declan,

One thing you do have to watch out for is that some servo's have the positive and negative wires reversed so always check that those two wires are in the same position, it can cause a lot of replacment parts bing required, as a mate found out...


Roy

[dpbarry]

Declan,

One thing you do have to watch out for is that some servo's have the positive and negative wires reversed so always check that those two wires are in the same position, it can cause a lot of replacment parts bing required, as a mate found out...


Roy

Cheers Roy.

Yes, I watched out for that one. As you can see, it was my own stupitidy in the end.

Declan

[Fast Electricals]

I had a similar problem the other day. My ESC is fitted with a safety device which will only "arm" the unit if the throttle stick is in the neutral position. The throttle trim lever had been knocked in transit and the motor would not run. After much head scratching, I finally worked it out.

Neil ???