Monday 19th. Drives stalling during slews.

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Monday: The AWR, RA, stepper motor drive regularly stalls during slews. I have tried tension screws to fine adjust the pressure between the worm and the 11" wormwheel. It didn't help and there was still lots of backlash due to the huge clearance between the worm and wheel.

Today I thought I'd try a tension spring. The theory being that any eccentricity in the worm wheel would be taken up by the spring. Absolutely hopeless! The slightest tension on the spring and the motor stalled. I checked the balance of the OTAs and that wasn't the problem. It poured down so hard during my slewing trials that it was impossible to hear the motor.

The next plan is to slack off the clutch screws in the RA wheel hub. Then I can check for concentricity without adding balance problems as an unknown variable. I can check the balance at the same time of course.

While it was pouring down I have pinned down the worst leakage. It is in the shutter joint half way up. I used a butt joint lying over a 40x40mm timber cross brace. Obviously not good enough despite the expensive filler/sealer. It was impossible to get plywood long enough to cover the entire shutter in one length.

Due to the geometry and position of these seams I cannot use aluminium profiles to ensure the rain passes straight over the joint. Rain would merely collect in the Z-profile. So I will have to strip the paint off and waterproof glue a strip of ply over the top. Once the glue has gone off it can be painted to hide the repair.

Further thoughts suggested sloping the tops of the patching strips outwards and downwards to throw the rain clear. Otherwise it would probably leak under the wide overlapping strip which weather seals the middle of the shutters when they are closed.

Tuesday: I was all set up for some solar imaging and it started raining. Grr? So I made a 15° reclining stand for the AWR IH2 drives paddle out of a larch upstand and a plywood base. I also drilled two leaning holes in the desk for the cables. It's a shame I didn't have any square drills. Or the holes could have been made smaller to just let the square plugs pass through. I have glued a small strip to the plywood base to stop the IH2 from sliding downwards. The IH2 is a nice snug fit so doesn't move about. It is now very pleasant to read and to use compared with upright fixing or lying down.
 

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