bought a 2nd hand mount. paying the price.

[AlexN]

Hey everyone. It's been a few years.

I have been bitten by the Astrophotography bug again and have assembled a fairly modest little setup.

My drama...
I bought a 2nd hand heq5 pro for a few hundred cheaper than a new one. I knew at the time it was probably a poor place to be skimping on price but I did it anyway.

The RA axis is sticky when the counterweights are on the eastern side. It's buttery smooth when the scope is on the eastern side and the weights are on the western, but flip it around the other way and it's sticky. So sticky you can't balance the scope properly with the scope on the wester side of the mount. This in turn makes tracking and guiding unpredictable at best and horrible at worst aiming east ..

I've stripped the axis down, cleaned and lubed it all, as I was piecing it back together I was checking range of motion and tolerances etc. It was all smooth untill I replace the setting circle. If I tighten the setting circle grub screw I can cause the whole axis to bind up. If I remove the circle completely the mount seems totally smooth.

Anyone got any experience with heq5 tuning that could shed some light on this for me?

Preferably if someone in Brisbane could help me nut this one out I'd be much appreciative.

[LewisM]

Alex,

I notice the same thing with my Vixen GPD2 IF - and ONLY if - I lock the polar scope setting circle in place.Seeing I do NOT use the thing, I simply unscrew the screw and place it somewhere safe. Nothing will fall out. I replace the screw at the end of the night.

So,just remove the screw In this day and age of GOTO, is the setting circles even needed, unless you go "old school"

[Eratosthenes (Peter)]

what sort of lubricant did you use on the gears?

Some people believe the setting circles on astro mounts are for show only, and not very accurate

[AlexN]

I used white lithium grease. The grease that was in there was quite thick, clear/very pale yellow. It was applied rather haphazardly throughout. It shows signs that it's been opened up in the past and judging by the meshing of the spur gears and the worms I get the feeling the previous owner didn't know what they were doing.

I've got a belt drive kit coming from the UK now too, but want to get it running 100% before fitting the kit.

[Eratosthenes (Peter)]

Originally Posted by AlexN

I used white lithium grease. The grease that was in there was quite thick, clear/very pale yellow. It was applied rather haphazardly throughout. It shows signs that it's been opened up in the past and judging by the meshing of the spur gears and the worms I get the feeling the previous owner didn't know what they were doing.

I've got a belt drive kit coming from the UK now too, but want to get it running 100% before fitting the kit.

the grease is critical. It needs to to be quite viscous and resist drying out or rubbing off the gears.

It's quite normal for very old grease to be much "thicker" and discoloured.

Inadequate lubrication or using the wrong grease can ruin the mount.

(white Lithium Grease is an excellent lubrication option, e.g Super Lube - Synthetic Grease")

good luck with the belt drive installation

[AlexN]

Just to be clear, the stiffness in RA was present as soon as I unboxed the moun.. It has become better since the strip down and re grease. Not to mention meshing up all the gears. It's better. But there is still a slight difference between balancing east and west side of the mount.. If anything it makes me biased to a slight east imbalance which is a good thing. But still I don't know how much it will affect tracking (I've not tested it since the strip and lube yet.)

[pluto (Hugh)]

My EQ6 does this too and I've read of others having a similar experience with their EQ6s. Even with the stickyness it tracks and guides fine.