TV 85 R&P issue!

[Chaz2b]

Hi,

my TV85 has a problem with its focuser, it’s the two speed version and as I rotate it it gets quite stiff/ sticky, then it rotates nice and freely before going s&s again, those words don’t sound right do they?

If I rotate the finer focuser there’s not so much of a problem, mainly with the main wheel. I tried adding some wd40 to see if there was wharf in there or to feel if one of the cogs is distorted but it didn’t really help.

This is a nice hunk of metal but it’s not doing it’s job well, is there a service centre in the U.K. that could help remedy this focuser?

chaz

[Peter Drew]

The description suggests some form of eccentricity, either on the drive shaft or one of the faces of the operating thumbwheels, I have experienced both in the past.

Eccentricity of a drive shaft can be caused by overtightening the pressure on the bearings in an attempt to cure slippage, that of a thumbwheel by having too little clearance from its face.  Has this always been a problem or a recent issue?

[Chaz2b]

I’ve not long bought it, second hand, the overall condition is good which hasn’t made me suspect misuse. The top pic shows a small screw hole to which I have no Allen key that fits, the second pic shows two silver grub screws, they go up and down, but I know not why and the third is as close I can focus on that small screw hole.

At first I though it was tight due to being un used, but it’s got slightly worse with the larger of the two wheels, same side, getting so stiff it won’t turn the shaft but itself rotates, then I turn the smaller wheel which frees up the larger one.

Edited June 8, 2021 by Chaz2b