Quote:
Originally Posted by gregbradley
Paul you got a dud like so many of us. I can't believe SB are still putting out crap worms. This has been going on for years now.
They will however send you a new one when you ask them which is good. Often the replacement is more like +/- 3 arc secs.
The replacement I got was good. My original worm wasn't bad originally but developed a spike in the PE which resulted in double stars in every image. Perhaps from the gear slippage from the tension rods not being set properly from the factory.
There is a good video by Chris Venter that shows the replacement process and its worth watching first. Its not that hard. The 2 tension rods on either side of the cam pins should be closed and then reopened 2.25 to 2.5 turns. I found it required trial and error to get those tensioned right. I would adjust it, then do a practice slew to see how it was going. If too loose the mount will slip easily if too tight it will stall at some point. So trial and error so its firm without slippage but not so tight as to stall. Too loose and you can also get oscillating guiding back and forth from backlash.
I wonder if they assemble these mounts themselves or if they are done in Mexico or somewhere or the components are made in Mexico. That would explain the QC issues that seem to be ongoing.
However once sorted it does give round stars. I think it will need periodic maintenace though to tighten up the cam and the tension rods. Maybe the mount "breaks in." Last time I used mine I started to get oscillating guiding again and all I did was make sure there was a slight imbalance to the east and it was all good after that. But I notice its starting to slip again with imbalances and it didn't after the last adjustment.
Greg.
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Yep have seen Chris's great video on this and will be doing that once I get a new worm. I am now certain this is part of the problem with the guiding I am seeing.
Those tension rods are spring plunger assembly and I am very familiar with those from servicing my PME. It seems I will not become expert in the PMX too.
