EQ5 RA knob has vibration on it.

[Spacehead]

Hi All.

Disaster has struck tonight.  I track using a fitted RA motor and its been great for about three years.  Then tonight, I noticed that the control knob on the mount for the RA was "thudding" very slightly with each motor pulse - ive never felt this before.
On looking at the photos, I have trails on stars at 1min exposure 

Can anyone advise me what may be wrong?  I changed the batteries but the result was the same.  When moving the RA manually with the control knob it seems ok - smooth etc.  But when the motor clutch is tightened, the thudding starts

[cletrac1922]

I have EQ5pro mount

Not sure how motor assembly is constructed internally

Now use SynScan WiFi adapter, with SynScan APP

Takes lot of guess work out of GPS, date/time

I also use car jump start battery pack to power my EQ5 mount

 

[almcl]

Is this the Skywatcher upgrade kit with the brass gears and steel brackets?  

If so, I found that occasionally the grub screws on the gears would slacken off, all by themselves. 

Also the positioning of the brackets and the motors on the brackets, while not readily adjustable, could make a difference to how well the system performed.  Making sure everything was square on and tight helped.