Thompson Saginaw actuator

[dunnsept]

The saginaw actuator on my dish finally gave up the ghost. I replaced it with a venture.. ok, back in business.
I want to check out the saginaw to see if it's possible to fix and worth fixing.
I have the motor apart, aside from a ton of dead bugs, everything seems okeedokee in there.
but as I was unscrewing the tubes, at 2 different points well before full extension, the tubes got really difficult to turn and it made some squeaky/grindy noises. I think the threads may be trashed in those places.
But, how do I get the tubes completely seperated?
(I know, I know careful of the balls in there but at this point the things is useless anyway)
at full extension, the inner tube basically quit turning. I put a little pressure on it and can not turn it anymore. also didnt want to get a cheater and put more force on it because I don't want to break it if there's something else I need to do first.
should the tubes just unscrew and come apart? If so, anybody have any ideas why it would just stop?

it also kinda surprised me that the sensor is actually a 6 point "star" wheel and micro switch. Switch sits on a small PCB with +5, gnd and pulse. unless the spring in the switch is weak, I don't really see how the thing could lose counts when moving. it's mechanical. just for fun I think I'll hook it up to my o-scope and see what it does.
TIA

 

[gabshere]

on the regular actuators there is a nut or screw at the base ( where the actuator arm connects to the motor). if yours has this then you can remove it and the arm should come loose (but still be attached) this would reveal a shaft inside the actuator arm with a pin that connects it to the motor . if your has this pin then removing it will completely disconnect the actuator arm from the motor. now on all the ones i've had apart and you've completed the above the outside arm should come offf by moving it up the inside arm shaft ( plus you would have to remove anything at the end of the smaller part of the arm that connects to the dish like bolts and spacers). this should reveal a good portion of the arm and maybe you could oil it.

 

[dunnsept]

ok, any tips on how to drive that little roll pin out?
I talked to the previous homeowner, he said that from the new install, he had to replace the actuator once. so this is the replacement .. would make it around 18-19 years old or so

 

[gabshere]

i tapped it with a very small screw driver and a 1/4 size ballpin hammer so it should work with other combos - ice pick and hammer

 

[dunnsept]

cool.. thanks! I'll give it a try and see what happens

 

[tvropro]

My old Saginaw gave up the ghost last January after 19.5 years. It was the brushes in the motor that wore out. I had my machinist friend rebuild it. He cut the commutator, and made new brushes from carbon stock. We greased it up and it works like new so I have a great spare. The new Sags are close to 4 bills so if you can get the old one going it's worth it. They are a workhorse and last a long time.

 

[dunnsept]

yea, I read that post and looked at mine. the brushes are fine. commutator is a little scored but not badly.
but there's definitely something wrong in the linear portion. as I unscrewed the inner tube, it suddenly got really difficult to turn, I could also feel it sort of 'grinding' inside. that's why I want to get the tubes seperated so I can inspect the threads

 

[dunnsept]

nope! went out and looked when I got home tonight. there is no pin on it. It looks like the shaft that pokes out the back of the arm has the coupling threaded on. completly rusted too.. I put some pblaster on it.. we'll see if I can break it loose