DG280B Backlash adjustment

[c_perrone]

Just a quick question for all the experts on this forum.

I'm sure some of you know of the motorized problems I had with my setup. The new motor (DG280B) has taken care of all of the moving problems I had in the past. Thanks again to all who replied and helped!

I noticed the other day that the motor shaft appears to have a bit of movement to it which it did not have when I installed it a while back. If I am standing at the dish I can "wiggle" the shaft back and forth which can cause the quality to drop or increase depending on which satellite I am locked onto.

So, I see this "Backlash adjustment" mentioned on Sadoun's page. Could this be my problem? What exactly does this adjustmet do and should I attempt it?

I have attached a picture taken from Sadoun's page of the adjustment screws and also I noticed that the 2 screws that are referenced in the picture also wiggle when I touch the dish with the slightest of pressure. Is this normal?

 

[Fizbi]

I don't have this motor, but just for fun I looked up the owners manual.

There are five screws involved; Read page 3:

http://sadoun.com/Sat/Products/PowerTech/SADOUN_DG240_User_Manual.pdf

I think this may fix your problem.

 

[Machman]

I've done the backlash adjustment as described in the manual on one of these motors and the problem hasn't returned so far. You'll need a 3mm wrench for those bolts, unless you can find a 15/128" somewhere. Don't use a 7/64" or you could damage the bolts. Just loosen the four of them up about two turns, tighten the screw on the side of the motor until the shaft no longer has any slack, and then re-tighten the bolts. Only tighten that little screw as much as necessary or you could shear it off (that's experience talking ) or even damage the gears.

 

[c_perrone]

Machman,

I know what you mean about that little screw....I did the same thing on my first motor(DG240)... My real question is should the four allen screws be tightened as much as possible after the adjustment? It appears on my new motor the allen screws "wiggle" a bit which appears to be causing the "loose tube" problem. Should they wiggle at all? I knew my first motor had a problem from the start as it was not moving at all from time to time, so I decided to try this adjustment. I am a little gun shy about messing with the new one... The manual is a little vague as it say loosen a little/tighten a little....

--Clint--

 

[Fizbi]

Clint,

My guess is that those screws should not move. I would tighten them until they stop moving. Based on your previous post, they probably did not move until after the motor got some run time.

One thing you could do is pull one screw out at a time and inspect them for damaged threads.

Another thing you could do is contact the manufacturer and get their advice.

I've broken my share of bolts, so I understand your concerns.

 

[Machman]

Clint,

The four bolts should be tight enough that they "stick" when you try to loosen them. I think it would be very difficult to damage them as they are fairly thick and appear to be screwed into metal sleeves inside the motor housing.

The way it works is that those four bolts are what hold the gearbox to the outer housing. When you tighten the little screw, it pulls on a metal wedge that pushes the gearbox more firmly into the gear that's attached to the dish shaft. This causes the gears to mesh more tightly so that there's no more slack. Tightening the four bolts clamps the gearbox into the desired position. If they are not tight enough, the backlash problem will appear again later.

If you want help fixing the broken screw, please let me know. I did it successfully on my DG-240 last night.