I purchased an EAF and a Starizona adapter to try the EAF on my TEC140 FT3545 focuser. So far the results are completely unacceptable. I have backlash over the maximun allowed in the ASCOM driver. Given the step size the backlash is approaching 1,000 microns! In contrast, my Microtouch focuser on the same focuser with same load had ~85 microns backlash.
On CloudyNights another user said he too had trouble with the EAF on this focuser and this suggests that the motor and gearing may not be siufficient to move this focuser accurately.
Has anyone here used the EAF on a large focuser with a decent, but not excessive load?
Hi Peter, I was using the ZWO EAF on an Askar 300mm refractor for a while and yes, it did have a noticeable backlash. I was however able to manage this ok with the backlash settings in SGP Pro focus routine.
I found the problem....my fault, but also a pretty stupid adapter mistake (in my view) by Starizona. The two mounting holes in the adapter that mate to the EAF are quite oversized. The bolts were rather tight, certainly not loose, but not as tight as possible which allowed the housing to slightly rotate on the EAF when reversing motor direction. I'm going to try to find or make a washer that can take up the completely unnecssary space in the adapter holes.
Either that or you could crimp the rivnut first if you have the tool and space/configuration then drill the thread out, I've done that on several occasions. Without knowing the bracket I couldn't tell you the best way but I know you are a very smart gentleman and it wouldn't take much inspection to work out what's best.
If using the aluminium rivnuts they will be easy to drill the thread out.
Sorry Peter for my lousy answer but I don't have the EAF, nor am I familiar with it, were I to have the stuff sitting in front of me I'd have a solution in minutes.
If that's a plastic adapter be gentle if you do use rivnuts.
If I had the exact size I could probably turn up some spacers out of some scrap round bar, steel, brass or aluminium if I have it (I may, I don''t know with the brass and alloy, I could have it) which would fit precisely and have the right hole for the mounting bolt.
That would only be OD, ID and thickness, it's a simple job on the lathe even for an idiot like me and I could chuck them in the post, you're not that far from me (but Auspost would have to send it via Sydney and Queensland first). They wouldn't be anodised or look like anything Joshua Bunn does but I am close and could get them there reasonably fast if you haven't found something yet.
Or you could pick them up if you were heading via Lithgow to the city sometime.
Apologies for going silent to your two messages. I've been rather ill for the past week, but fortunately have turned the corner...worst gastro in my memory!
In any case, the EAF is packed up and returned. While there are issues with oversized holes on the bracket device that clearly wasn't the problem. Under no load, the EAF appered to have little to no observable (to the eye) backlash, but under load had uncorrectable backlash. Given the same focuser runs acceptably well with a different brand motor I don't see how the focuser could be at fault.
Anyway, I wasted quite enough time! Thanks for your input!
I hope you are feeling better now Peter!
There's nothing worse than time wasted trying to figure out issues with any equipment, especially when the equipment itself is faulty and you search for every answer assuming the goods to be as marketed.
