16.11.2020

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Monday 16th. Rain and gales! The postman came early, bringing new toys. I have a smart little fuse box and sweety bags of assorted, blade fuses. From 2A to 7.5A. These will protect my mounting and associated equipment from the new PSU. 12V at 12.5A.

A big, round, graduated bubble level is fun and was cheap and cheerful. There were no useful surfaces for a builder's level on the mounting.  So I will lay the round bubble level on the mounting base plate. This will allow me to quickly and easily check any change in level of the massive pier. 

Two 40mm cooling fans for the PSU are on their way and will also arrive today. [Delayed in transit] The plastic PSU case hasn't been dispatched yet. So that job is on hold.

I can drill and fit the U-bolt to the PA motor plate for the longer turnbuckle. It is probably best to remove the motor plate. Which is trapped by the lower, PA, flange bearing. That should be fun! I'll have to take the newly added weights off the wormwheel and spacers. Then undo the four 16mm nuts to allow the flange bearing to slide off. Only then can the motor plate be freed. 

I hope the weight of the instruments and their balancing counterweights will allow me to remove the lower flange bearing without a struggle. I may have to employ the pulleys to help relieve some of the top-heavy weight. 

Next time I should remove the telescopes! It was a real struggle to remove and replace the flange bearing and motor plate. Only when I relieved the pressure on all the fixing, including the latitude pivots, was I able to get the bearing on and off. Just as I intended when I designed it all in my head. Compression in all planes via the contacting studs. [All threads.] 

The new turnbuckle seems to work much better than the previous one but I shall still oil it. Helping to reduce friction even further. It did. I can now adjust the PA altitude more finely by hand strength alone. The old turnbuckle needed a lever to turn the body.

While I had the drive separated I counted the number of teeth on the timing belt pulleys.[Several times.]  I must have done this several times before in a desperate bid to discover why the Goto slews are so utterly hopeless. But no, they were to spec. 14:34T. The overall drive ratios seems to be okay too. The AWR factory build sheet shows 14/34T x 287T x 200 = 139400. 287 is the  number of teeth on both wormwheels. 200 is the number of motor pulses per rotation. I'll check the factory specs again on the AWR IH2 handset/paddle tomorrow. 139400. Okay. It is correct on both axes. So that's not the problem.

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