#iEXOS-100 altitude knob loose #iEXOS-100

Jaimie Murdock

Hi all,

After moving my mount to a new location, two odd things happened to the altitude axis:
1. The screw on the left side of the mount’s altitude dial shook loose and came out. I reinstalled it but am unsure of how much tension to apply. It seems to move smoothly, except…
2. The altitude knob now has quite a bit of play before it “catches” and adjusts the axis - I’d say about 1/8 of a turn. Before it was tight and the altitude axis adjusted immediately.

Any ideas to retighten the axis? I’ve found 2 set screws on the knob itself and a screw on the base, but am unsure of which to adjust.
Mount: ES PMC-8 iEXOS-100
Scope: William Optics ZenithStar 61II w/ UniGuide 32mm
Cameras: ZWO ASI533MC, QHY-5-III-462C
Software: KStars on Astroberry, DeepSkyStacker and Photoshop

Jennifer Shelly


Tighten the set screws on the knob. Just make sure you are not using the rounded end Allen wrench (usually the long end) and use the flat end (the short end).  The set screws are aluminum and it is very easy to strip the hex socket.

Jennifer Shelly
AstroPorch, VA

Mounts: ES PMC-8 G-11, PMC-8 EXOS-2, PMC-8 iEXOS-100
Scopes: ES ED127 FCD-100 f/7.5, N208CF f/3.9 / Askar FRA400 f/5.6, FRA600 f/5.6 / Meade LX850 10” ACF f/8 / QHY Mini Guide Scope f/4.3 / Solomark F60 Guide Scope f/3.6
Cameras: QHY600M, 128C, 168C, 183M, 5III174C
Misc: MoonLite CFL 2.5, High Res Stepper, V2 Mini Controller / Baader SteelTrack NT, SteelTrack SC, SteelDrive II, UFC, 2” LRGBSHO CCD / Optolong 2" L-Pro, L-eNhance, L-Extreme, 1.25” LRGBSHO CCD / QHY CFW3-L, CFW3-S, OAG-M / Primaluce Lab Sesto Senso 2
Imaging Software:  NINA, APT, SharpCap Pro
Processing Software: PixInsight / Adobe Photoshop, Lightroom, Premiere Elements

James Ball

Also, if you wiggle the knob side to side as you slowly tighten the setscrew, it will move less and less as you tighten.  Once it stops moving side to side you should have the setscrew centered on the flat section of the altitude screw shaft, so after  you tighten completely it will be the most secure.
James Ball
Dawson Springs, Ky
Mounts: iEXOS-100
Scopes: Meade ETX90RA(deforked now) Sky Watcher 150MCT
Camera: ZWO ASI 120MC-S
Software: Explore Stars Android, ASCOM, Stellarium Scope, Stellarium, AS!3, SharpCap, RegiStax6.