Re: Mach1 (spring loaded vers) has gear slop?

Ron Kramer

The wiggle in RA when I wiggle the counter weight shaft.  There is a instruction page that shows you losen the 2 screws and apply thumb pressure then tighten the two screws. 
I did this a year or two ago and and it worked GREAT.  Now when I try it seems there is no room for me to push on with my thumb. SO doing this does not remove the slop/wiggle in RA. 
Manual titled  Auto Adjusting gearbox no more work meshing. 

This thumb action in photo no longer takes out wiggle.


On Mon, Apr 20, 2020 at 1:11 PM uncarollo2 <chris1011@...> via <> wrote:
Give George a call at AP and he will run you thru how to adjust your mount gearbox. From your description below I do not get a clear picture of what you are trying to adjust.

Roland Christen

-----Original Message-----
From: Ron Kramer <ronkramer1957@...>
To: main <>
Sent: Mon, Apr 20, 2020 11:46 am
Subject: Re: [ap-gto] Mach1 (spring loaded vers) has gear slop?

It's gotten worse and I keep thinking about that slop.  If it doesn't matter like you say, then why does the manual show how to take out the slop and tells me to check it by moving the counter balance weights. I do it  "AS THE MANUAL," tells me to?  but the thumb on the box doesn't seem to have any more play?   Last time I did this is worked, now it doesn't. 
Last night I was RMS 2.0  (really getting super poor).  

On Tue, Apr 7, 2020 at 3:52 PM Ron Kramer via <> wrote:
Thanks Rolando. I wondered if it was "sky" but seems to have been bad a month or more.  But you're sharing pretty much same skies as me. So I'll see how it goes.  Thanks for the reply. 
Still my shots have been fine.  (does this new group allow images?)   I HOPE... Y4 and whirlpool during recent 1/2 moon.

C-2019 Y4 Atlas-Small.jpg  

whirlppool_final---CROPPED 15300.0s-AR_LN_8.0_4.0_9-x_1.0_LZ3-NS-full-qua-mult-sc_BWMV_nor-AAD-RE-noMBB-mod-lpc-cbg-mod-lpc-cbg-lpc-cbg-St.jpg

On Mon, Apr 6, 2020 at 7:44 PM uncarollo2 <chris1011@...> via <> wrote:

So my question is there another method or documentation of what I might do to take that play out of the RA mesh?
There is no reason to take out any play in RA. That axis is always running in one direction and is never reversed, so play or backlash is not an issue. It doesn't come into play at all during tracking or guiding. Leave it be.

Run Guiding Assistant and look at the natural star motion when the mount is not being guided. It will tell you instantly what the stars are doing, how much they are moving due to atmospheric motion. If you get 1 arc sec RMS of natural star motion (scintillation) then no amount of guiding will get you less error. I recently checked my skies here in Northern Illinois when it was clear on Saturday. Stars were moving around so much (probably jet Steam) that i had 0.8 arc sec RMS values of just scintillation. I could not get better then that all night long with any guide settings. It's just the way things are in spring time around here.


-----Original Message-----
From: Ron Kramer <ronkramer1957@...>
To: main <>
Sent: Mon, Apr 6, 2020 5:41 pm
Subject: [ap-gto] Mach1 (spring loaded vers) has gear slop?

I was having superb performance over the last year. Total RMS guiding down around .24 - .32
I had some time away while swapping scopes from V1 RASA 11 to a V2 RASA 11. (very similar) V2 seems heavier. I rebalanced.
My guiding is now at best  .99 and averages around 1.50.  Good enough for decent stars at my image scale but it makes me concerned. The corrections are very abrupt. I've used PHD2 for 3 years and know it quite well for tuning. I can't seem to get it to smooth out.
I believe there was a PHD2 update during this  (good to bad shift). so it's hard to know if it's the mount or phd2. 
With that said - I feel there is a good bit of play in the RA mesh. I have taken the slop out before using the 'thumb pressure" tuning trick.  That isn't working this time.  I move the weights/top of teh scope a good bit that I think is the culprit. 
I opened the RA end of the box where the 3 gears are. (the middle gear turns freely easily). But it too seems to have some slop. ?  Meaning I can wiggle the middle gear1 bit (1/16th?) inch or could say 1.5-2mm or so before it contacts the other gears to make them move.
So my question is there another method or documentation of what I might do to take that play out of the RA mesh? 
I have seen the instructions for (old-style - no spring-loaded vers) which doesn't apply to me I don't believe. As noted above, the thumb/finger pressure on the release lever doesn't seem to work this time. Could this mean a new gear is needed in the box?  What else could I try?

Ron in Grand Rapids, MI



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