ZWO EAF randomly stops during Goto and double beeps

chris_g

Hello,

I've just installed an EAF on my telescope, an EvoStar ED80. I've set the zero position with the draw tube fully retracted and the max number of steps to 60000 using ASI Studio. Now the EAF sometimes stops before completing a Goto and double beeps. If it completes the Goto it does not double beep. Sometimes it will move as much as 10000 steps with no issues and other times it will only go a few steps before stopping and double beeping. It does this in both ASIStudio and APT.

Can someone please advise as to what the problem may be.

w7ay

chris_g Can someone please advise as to what the problem may be.

Insufficient torque to overcome the friction from your OTA's focuser and drawtube.

Among possible fixes:

1) Make sure your focuser locking knob is completely removed -- you don't need that since the stepper motor of the EAF will hold the focuser in place without being backdriven. If you have used the locking knob's hole to hold the EAF, that bolt may be too long and locking the focuser.

2) Make sure the EAF shaft is perfectly in line to the focuser shaft: don't depend on the flexible coupler to rotate the focuser on a badly aligned shaft.

3) strain relieve the USB cable and 12V cable (if 12V model). Use cable ties/velcro straps/Gaffer tape) to hold the cables down tightly. If 5V model, make sure the USB port has sufficient current drive.

4) make sure no cable is holding up the drawtube from moving freely. In the cold, cables can become very stiff.

5) If it is happening when your OTA is pointed high in the sky, it could be caused by the weight of the focuser payload exceeding the capability of the EAF. That will exacerbate the above problems.

Chen

chris_g

Thank you, Chen, for responding and pointing me in the right direction. The issue was with the set screw that holds the shaft of the focuser against the focus tube. I had removed it thinking that was how the EAF bracket would mount to the focuser. When I put it back in, I did not tighten it enough and the EAF was slightly out of alignment with the shaft itself.