24" Von Weise actuator only extends 12"

[sliderule]

Just got a C-band dish last week which has a V76-5 actuator. It's all in great physical condition except for needing some paint touch here and there. Using a 12 volt car battery, the actuator will extend out to only about 12" and then stops. Retracts properly. I understand there's a couple of travel limit switches somewhere. Is the extend switch faulty? Where is it so I can inspect it? I partially disassembled it yesterday.

Thanks!

 

[Titanium]

With the actuator cover removed, you should see a cam wheel (with two stacked layers) that rides against a switch. The cam has two screws that are loosened to allow each of the two cams layers to rotate the raised point to contact and open the switch at the desired point of rotation (tube extension). This switch opens the power circuit and cuts the power from reaching the motor.

One cam is for retract and the other for extend (east / West). Extend the tube until the motor stops then slightly loosen the cam screws just enough to rotate the cam that is in contact with the switch to a different position to allow additional travel. Trial and error will get the cams coordinated with the desired mechanical stop locations.

Be careful not to allow the arm to extend or retract too far as to damage the actuator or the dish!

Attach a photo of the inside mechanics if you have trouble identifying the cam and mechanical switch.

 

[Magic Static]

As Titanium stated there are two cams but only the upper cam (extend limit) is adjustable. The lower cam (retract limit) is set by unscrewing and screwing in the inner tube of the actuator. This lower cam typically would never need to be adjusted unless you ran the actuator motor without it being installed first.

 

[sliderule]

Got it, thanks! I now see that there is a micro switch that rides against the upper cam wheel which has 2 adjustable slots. It is presently set at about 1/2 way from each end of the slots which I imagine means about 1/2 way of the max travel.

 

[wvman]

As Titanium stated there are two cams but only the upper cam (extend limit) is adjustable. The lower cam (retract limit) is set by unscrewing and screwing in the inner tube of the actuator. This lower cam typically would never need to be adjusted unless you ran the actuator motor without it being installed first.

I had a customer years ago that fooled around and got his Von Weise out of adjustment and ran it down and jammed it. We fooled with it for over an hour and couldn't get it broke loose. He messed with it later that evening and buggered up the lead screw and had to buy a new arm.

When I first had trouble with the nylon nut stripping out in these arms, I took a piece of Oil Lite stock and turned out about 20 on my lathe. From that point on, the first thing I did was replace the nylon nut with one I made and never had a problem with another one of them. I had some out there that were 15 years old and still working.

 

[Cham]

Mine (Von wise actuator) must be 20+ years old, new mid 90's. Still works fine, but does have just a bit of play in the nylon nut. I did take it apart a few years ago and cleaned /lubed everything inside, even the motor bushings. Also replaced the motor brushes. These are well made units built to last, especially if taken are of. Never had to adjust the stops though.

 

[wvman]

Mine (Von wise actuator) must be 20+ years old, new mid 90's. Still works fine, but does have just a bit of play in the nylon nut. I did take it apart a few years ago and cleaned /lubed everything inside, even the motor bushings. Also replaced the motor brushes. These are well made units built to last, especially if taken are of. Never had to adjust the stops though.

If you know someone at a machine shop or someone who has a lathe, have them make you a new nut out of Oil Lite Stock. Von Weise uses an Acme thread for their nylon nuts. They will last years longer than the Nylon and if they cut the new nut to tight tolerances, it will be more accurate as well, and they're self-lubricating.

Those arms were originally designed for hospital beds. No need for tight tolerances in applications like that. Great arm, but the nuts were the weak point.

 

[Magic Static]

Lone Gunman made a nice thread on repairing the Acme nuts
Von Weise Actuator Nut Repair?

 

[Cham]

Not sure if I could handle my movable C-band dish being out of service for the time it would take to have a nut made up!
I have another actuator I could use, think it is a ball-screw type...

 

[SatPhreak]

Cham, if you have a ball screw actuator is the best type of mover. They last and last and last.
20 years of use and they still work. Pull it apart, check grease or oil and mount it up.

Sent from my P00A using the SatelliteGuys app!

 

[Inno]

I remember being able to buy replacement Acme nuts for these things maybe 20 or so years ago.....ahhh the good old days. I think at the time you had the choice of nylon or brass......but I may be remembering incorrectly.

 

[SatPhreak]

When I bought a house with a Cband dish in '97, it had a nylon nut included in the deal (because the original nut had failed) so I installed it and got the dish running for 5 years until the motor on the mover died. At the time I was looking for motors the nut was still available. I still have 1 Cband installer in my town (he mostly does Shaw Direct now) so if you look around, especially online, you should be able to at least get the nylon OEM nut.

Sent from my P00A using the SatelliteGuys app!

 

[sliderule]

Thanks for all the advice. I really did get lucky on this dish. Actuator works and nothing is damaged or missing. I am doing some media blasting in the driveway this week for a car I'm restoring and will blast the polar mount assembly and repaint it. Most nuts 'n bolts could be reused but will probably replace them. I looked at a 10' BUD nearby last winter and it looked like a truck had backed into it. I didn't take it but now I kinda wish I had for spare parts.

I went back to the people that were giving it away and dug up the 10' steel post. Whew. I thought I could break off most of the concrete with a sledge hammer but only got about 1/3 of it off. Used a come-along to pull it out of the hole and then I was able to drag it about 100' out to my truck with a long chain +rope. Fortunately the owners were there and helped me lift the heavy end into the truck. I was also able to salvage nearly 100' of Commscope dual coax ribbon cable (has 16 ga. actuator wire). It was only buried an inch or two in the ground along the fence line and all I had to do was pull it up. That also is in good shape. Had to leave some in the ground because it got deeper towards the house and roots were in the way. Weird thing was there was also some Norsat dual ribbon cable but with smaller (#18?) gauge actuator wire. Seems like it was abandoned. Maybe it failed or the smaller actuator wire was too small due the dish being about 200' from the house? I also pulled that up and it looks okay but likely will never use it.

BTW, I was able to get this 10' dish down myself. I lashed an 8' extension ladder to the pole (top and near the bottom) and had the top rung a couple of feet above the top of the polar mount. I used a nylon tie down strap as a winch to take the weight before undoing bolts, after removing the LNB & attachment arms. The dish itself is fairly light but with the dish on the ground it wasn't easy to reach 5' into the center to undo the bolts without damaging anything. All told, I think it was just over 2 hours by the time I got it all on the ground, loaded into the truck and tied down for the short trip home.