Simblaster problem

[digigarb]

Been using the Simblaster USB interface with Planemaster and FMS but am having trouble with the controls jumping around.
Its connected to a Futaba 6XA. Even after calibrating in the control panel I can see the cross jumping around.
Has anyone had this trouble. Searched around but couldnt find an answer.

Thanks Graeme

[Zaragon]

I don't know anything about the Simblaster or the 6XA but I would check for good connections on all the plugs especially into the TX as a broken wire could have that effect as could dirty connections.

Also if you still have the 6XA transmitting RF then this could also have an effect, make sure the crystal or RF module is removed.

[digigarb]

Thanks for the reply Zaragon. I've checked all the connections and everything looks fine. I take out the crystal also. The strange thing is after I callibrate the controller and watch the little cross in the callibration box it jumps around slightly with almost perfect timing. Every second it 'pulses' around??

Graeme

[Zaragon]

Is it noticable in the sim, if not then I wouldn't worry too much about it. I can't remember how sensitive FMS is to tiny control movements, other sims may show it up more.

Of course you could just pretend it is local wind :-)

But seriously, some other things to check out. Tiny movements in the position could be because the converter is digitising the signal. There is only about 120 ish different levels and it could be just right on the edge of chosing the next one. Minor variations in power levels or anything else going on in the TX could just tip it over. Try adjusting the trims slightly (you can negate the effect of trim by recalibrating).

Does it do the same thing on a real receiver/servos. If it does then it would be worth having the transmitter checked out.

If you have access to an oscilloscope you could also take a look at the output signal to see if it is stable. There are some software ones around that work with the sound card but these may not be accurate enough for this purpose but worth a try.

If you are running the USB interface into a USB hub try plugging it directly into the computer especially if there are also other devices plugged into the hub. Though this would tend to just make things slow to respond not be unstable.

[digigarb]

Thanks again for your help. Yes it is very noticable when flying any sim with it. As I fly around the model will start jerky movements. As an example the model will start to bank with the ailerons by itself. But not smoothly. It does jerky movements as if it&s doing a 200 point roll.
I&ve sent an e-mail to simblaster to see if they can help but no reply yet?
The strange thing is it is intermitant but it will always do it at some stage.
I&ve even elliminated any chance of static as I read some other people solved their problem this way.
Graeme

[digigarb]

Just for anyone else who may have a problem moving the trims to one side seems to have fixed the problem!! :eek:
I will only get a small glitch on occassion now. It is now flyable in all my sims!! :)
Thanks Zaragon for the tip!
Graeme