First hop-up goes horribly wrong ...

[KnightAzul]

I have an Thunder Tiger TS-4n Sport 4WD (RTR) and noticed that the steering was not tracking well. After some discussion on a previous thread (thanks SkyMaxx!) I ended up buying as a first hop up:

- HiTec Aggressor CRX digital 3 channel transmitter + receiver combo, which came complete with one HiTec HS-325HB servo.
- Ko Propo FSA-1 Failsafe.

Due to this being my first hop-up and also not having all of the right tools (typical of a newbie!) I managed to take shear off a small (0.5 cm) section of the sleeve off of the antenna near to the receiver. The wire was exposed slightly but not cut. Nothing a bit of electrical tape can't hide!

After having finished with everything prefectly tie-wrapped, a flick of the receiver switch (transmitter off) and my pride and joy is break-dancing! Both servos, steering and throttle/brake, are going mad and tending towards one direction (brake on, steering full-lock right). If I wiggle the antenna wire then this seems to affect the servos even more.

All of the evidence points a thick sweaty finger at the antenna. I though it worth a post in case it could be something else with this being my first hop-up and all. Could there be an appliance in my house which is causing this? and the electrical tape really is doing a fine job?

Thanks,
KnightAzul

 

[KnightAzul]

Just out of curiosity why does the throttle/brake servo return to it's neutral position when the receiver is switched on (without the transmitter being on), but the steering servo stays where it is?
Would this have something to do with the throttle/brake servo being connected to channel 2 on the receiver rather than channel 1? Is channel 2 always used for the throttle/brake?

A very confused ...
KnightAzul

 

[RandyT]

You keep saying without the transmitter on. Does it twitch with the transmitter on also~? You always turn the transmitter on before you turn on the receiver. If it still does it, try removing the failsafe. Did you try the new tx and rx before putting it in the truck~?

 

[Domination]

Originally posted by KnightAzul
a flick of the receiver switch (transmitter off)

first turn the TX on and make sure you have fresh batteries

 

[SkyMaxx]

Prior to placing the linkages on the servos, did you power them up and allow them to center on their own? If not, that might be a part of the problem.

My money is on interference with the failsafe. Sometimes certain failsafes and radios just don't mix well. You may have found just such a combo.

I second or third the advice of the others with respect to always turning on your transmitter prior to turning on the receiver. AND most certainly doing both in that order prior to turning on the engine.

 

[lykan]

If I turn on my car with the TX off in the house, the things goes all weird, and it is totaly dependant on where I am in the house. I have several computers, and lots of other electronics, I couldn't care to guess at what all is in the house (not to mention 110 wires all over inside the walls.)

I can walk to the kitchen and the throttle is pegged, walk to the computer room, and the steering servo twitches like mad.

The second I turn the tx on, everything centers and no more jitters. This is because the TX has a stronger signal than any of the interference in my house. Outdoors it's not as bad, as long as nobody talks on a amplified cb heheheheh.

Anyhow like they said turn on the Transmitter and see if it's still getten jiggy with it. I bet with good tx batteries you want have this problem (just a guess)

It could then again be the failsafe as /\ said

 

[KnightAzul]

Thanks for the replies! It turns out that it may not have gone so horribly wrong as I first thought ...

Prior to placing the linkages on the servos I centered them manually. Bascially turning the arm through the full travel (approx 180 degrees) and returning it back to the centre point. I then attached it to the steering with the steering dead centre. Is this ok?

I tested with the failsafe removed in terms of cabling, but not physically from the chassis. The problem still remained. I also tested with new batteries but to no avail.

When I turned the transmitter on it returned back to normality with full control over the throttle and steering. My money is now on interference from testing the house. As a test, I ventured out to the patio and things got better without the transmitter on.

So, lessons learnt:
1. Inside the house is not a good place for testing due to possible interference.
2. Always turn on the transmitter prior to turning on the receiver.
3. Buy the proper tools!

Now I'll hunt down a shop which sells heat shrink to seal the antenna sleeve, as the electric tape had come off by itself this morning.

Thanks again for the help. Without this forum I would be completely lost. Excellent stuff!!

KnightAzul

 

[RandyT]

It's always transmitter on then receiver on. I still don't understand what your trying to do with the transmitter off. Are your trying to test your failsafe~? With no transmitter signal you will almost always get glitching.

 

[KnightAzul]

Dual Rate and servo installation

Prior to placing the linkages on the servos I centered them manually. Bascially turning the arm through the full travel (approx 180 degrees) and returning it back to the centre point. I then attached it to the steering with the steering dead centre. This was of course before reading in the instructions that the linkage should not be mounted before turning on the transmitter and centering the trims and sub-trims. However, I would maintain that the two methods are equally valid?

After spending a few minutes testing with the transmitter, everything is fine with full lock to full lock working. Steering centre was adjusted slightly with the trim, and left full lock was adjusted slightly with the End Point Adjustment. The adjustments were done with Dual Rate at 125% = maximum steering.

Ok, so now comes the part that I don't understand. I set Dual Rate at 60% = minimum steering (just to see what happens) and lo and behold full lock right is as before, but left turning has been reduced to almost nothing! I assumed that the Dual Rate would reduce the travel equally between left and right steering from the centre position.

Have I mounted the servo wrong? and my theory that the manual method for centering the servo without using the transmitter is not valid.

Thanks for any help!
KnightAzul

P.S RandyT: Basically I didn't know that it was transmitter first and then receiver ... a newbie mistake!

 

[SkyMaxx]

Dual rate as I understand it simply applies steering at different ratios. For instance if you throw in a full turn to the right, the servo moves slowly through the first portion of the turn (based on your rate percentage) and then moves at full speed through the rest. This still should give you full throw to throw movement of the servo.

As for manually centering the servo, I would not recommend doing that. Any time you manually run a servo (with or without power applied) you take a chance that you may strip something internal to the servo.

I recommend placing the servos in their trays without linkages attached. Put the transmitter on with no trim inputs and power up the system. Let the servos settle down for about thirty seconds, then give them full throw to throw inputs and then let them settle out again. This is to make certain that they center or move to their neutral positions.

Once, they are at their neutral positions, attach linkages in such a way that the device being controlled is at its neutral position (steering centered and throttle at idle). From there it is just a matter of adjusting linkages to the best effect and then tweaking the trim to sweeten it up.

 

[KnightAzul]

On the HiTec Aggressor CRX digital 3 channel transmitter, Dual Rate adjusts the overall travel of the steering servo. This is quoting from the manual. Perhaps other manufacturers use this to mean something different, just confuse everyone.

Anyways, I followed your advice and re-centered the steering servo us¡ng the transmitter without any trims, and hey presto everything works as it should do, including Dual Rate!!

Many thanks for the help!
KnightAzul

 

[SkyMaxx]

LOL...glad to hear it is fixed.

As for the HiTec directions, I'll have to recheck my own. I use the HiTec Lynx 3D full synth radio set up. I don't really play with the dual rate part, but read about it.

 

[CorradoPsi]

nevermind