Commanding actuator causes servo to move.

[goaliebob99]

I am throwing this up here to see if anyone may know what's going on or what would cause this.

I have been working with Brian on an issue with my ASC1. His support has been really good and we are still working on the root cause of the issue on how to correct it.

So when I command the ASC to move east or west, the servo motor does a rotation with it. When commanded west the servo will also do a counter clockwise rotation. When the asc is commanded east the servo will do a clockwise rotation. This is an issue because the servo hit's it's hard LNB limit and causes the asc to begin a voltage draw on the 5 volt dc port, going down to 3.5 to 3.8 volts before the unit resets.

I am not understanding why the servo motor has to move at all when the dish is commanded to move, and really should only move when commanded to via selecting the H or V pol, or when commanded to move to a certain position within the pol. When the 5volt line is disconnected from the ASC the dish moves fine and obviously the servo doesn't move because no power is applied to the servo.

The other weird part was tonight when I was rewiring everything (soldering) versus screwing the wires on to the wire bridge, I could hear the servo move a bit when the reed switch was connected. Is there any way that the reed switch is causing issues with the servo? Coincidental?

Thanks.

 

[primestar31]

Most important question: Did it EVER work right, or has it always been like this? Maybe a shorted shunt capacitor you installed for false counts in the line?

How was this originally controlled? Old IRD?

 

[goaliebob99]

This was originally controlled via a Vbox. I was running an orthomode C band. I wanted to add KU and not spend 400 bucks on an orthomode KU / C combo. LNB. It's been like this sense I put in the ASC. No shunt capacitor at all. All wiring is 1:1. No bends or anything in line. Wiring connects directly from the ASC to the actuator and servo via a direct connection. The LNB wiring is LNB to a 22khz switch. Nothing fancy.

 

[KE4EST]

Does it do this if you manually press east or west to move the dish?(With the receiver coax still hooked to the ASC1)

Does it do this if not hooked to your receiver.(Disconnect the coax leads from the ASC1).
In other words if you had it set for a stand along unit and you have to manually move the dish.
I know this would negate the purpose of having the receiver communicate with the ASC1 to change polarity. I am just curious.(but leave the servo wires hooked up, obviously to see if the servo rotates with dish).

 

[primestar31]

I'd like to see you take the ASC1 right out to the dish, (long extension cord) and connect to the actuator and servo with a different SECOND short piece of cable (after disconnecting the original long one). Then try it...

I suspect your regular (buried?) house-to-dish cable has a problem of some sort. Or did you bond the wires together somewhere, to extend them? Somehow you have a short of some sort... Maybe pinched some wires under a metal screw-down cover?

 

[goaliebob99]

Yes, when manually moving the dish with the receiver coax hooked up and it does it as well as if the coax is disconnected it still does it.

 

[goaliebob99]

I'd like to see you take the ASC1 right out to the dish, (long extension cord) and connect to the actuator and servo with a different SECOND short piece of cable (after disconnecting the original long one). Then try it...

I suspect your regular (buried?) house-to-dish cable has a problem of some sort. Or did you bond the wires together somewhere, to extend them? Somehow you have a short of some sort... Maybe pinched some wires under a metal screw-down cover?

The wiring is all brand new. Ran through PVC pipe. It's about a 100 foot run. It's all PVC from the dish to where it enters the house. It's a standard grey cable box. No wires pinched. I all ready double checked the system. I am beginning to think about ordering new wire and re running it.

 

[primestar31]

If you take the ASC1 out to the dish, and use a separate wire(s) (different), you can possibly eliminate a LOT of trouble-shooting very quickly...

 

[Magic Static]

Sounds like a poor ground issue. Check your "F" fittings. Look for wiring problems. Do you have a electrically noisy fluorescent light fixture?

 

[Titanium]

I have also suggested that the ASC1 be taken out to the dish and connected with temporary jumpers to confirm if this problem continues. I propose the same suggestions and cause like the other members .

As you have both the original ASC1 and the advanced exchange unit and both had the same issue, please test with both before returning the replacement. If the servo circuit is not connected, do both the original and the replacement ASC1 units operate without error? If so, this is the same configuration that worked on your Gbox before adding the servo and introducing into the distribution wiring.

The servo circuit is always active, not just during a movement. The only time the servo command changes is if the polarity is changed. The ASC1 does not issue a polarity setting command when the motor is moved.

Since you have replaced the generic servo with a Chaparral servo we can compare operations. If the servo is moving when no polarity change is called on either servos, the cabling is suspect. Did the cheap servo flutter after a polarity change? Does the Chaparral servo flutter after a polarity change? The main difference between a Chapparal and a generic version is the Chaparral already incorporates additional isolation (like the capacitor mentioned in the ASC1 FAQ).

Servo movement is likely caused by extreme noise masking the control signal at the servo. Once again, I will ask about the wiring. Please describe the type and configuration of each of the servo and sensor wire bundles including the ground shield and exact connections. Maybe include a photo of the wire bundles?

If you disconnect the servo that is installed on the feedhorn and instead connect the servo inside directly to back of the ASC1, does the servo flutter or drive to the limit when the motor is moved?

How is the dish grounded? Is the dish ground bonded to the structure ground?

 

[FaT Air]

Is the drain lead (braided) of the servo group grounded? If so, I'd try moving the gnd connection directly to a cold water pipe. If you're running the coax thru a grounded ground block, maybe try grounding the servo drain lead there/ and only there(?)

 

[Corrado]

Mine used to have a capacitor at the servo motor leads to prevent the servo flutter many years ago. That solved the problem I had.

 

[Cosmo Blatz]

I agree with the others here! Take the ASC1 out to the dish.
Disconnect ALL the cables running to the house. Take off everything!
Splice on new cables (right at the components) for the servo, actuator pulse, and actuator drive.
I'm betting everything works fine at the dish.

 

[Titanium]

One important thing that I just noticed as I reread the first post about connecting the reed switch. The Master Power must be OFF when making connections. No better way to toast a component or scramble logic than to hot connect.

Hot connecting is sending noise through the wiring. I would think that it would be quite normal for the servo to react to both switch contact as well a motor noise.

 

[KE4EST]

The wiring is all brand new.

What kind of wire did you use?

 

[Cham]

Sure sounds like a noise issue, are you using the shielded servo (polarotor) cable or an unshielded cable? If it is shielded make sure the shield is only connected at one end, to the ASC1 ground lead, I think that is the best grounding point other than directly to the house wiring groung (which in theory you would be doing if connecting to the ASC1 ground lug/screw, the power cord and socket has the third grounding prong to do this). Connecting the shield at a second grounded location might actually introduce noise.
Don't think there is cointinuity to ground through the feedhorn/dish since the servo is in a plastic case.

 

[goaliebob99]

Sure sounds like a noise issue, are you using the shielded servo (polarotor) cable or an unshielded cable? If it is shielded make sure the shield is only connected at one end, to the ASC1 ground lead, I think that is the best grounding point other than directly to the house wiring groung (which in theory you would be doing if connecting to the ASC1 ground lug/screw, the power cord and socket has the third grounding prong to do this). Connecting the shield at a second grounded location might actually introduce noise.
Don't think there is cointinuity to ground through the feedhorn/dish since the servo is in a plastic case.

The dish is grounded at it's own grounding block on its own ground. I cant wrap the house in ground wire to connect to where the service ground is. It's completely on the other side. I had to put in a ground rod specifically for this. I am using standard 14 gage wire found at the hardware store. It came pre rolled with 7 wires together at ace. You can buy it by the foot.

I agree with the others here! Take the ASC1 out to the dish.
Disconnect ALL the cables running to the house. Take off everything!
Splice on new cables (right at the components) for the servo, actuator pulse, and actuator drive.
I'm betting everything works fine at the dish.

I wanted to do this tonight but with the storms we are having, I am going to wait until tomorrow or later on this weekend.

What kind of wire did you use?

Standard 14 gage wire that came prepackaged by the foot. It was bought at Ace. See pic. This was a discarded part of the cable I cut earlier because when I stripped the jacket of the cable I cut into part of the wires that were around where I stripped the jacket. I am most likely going to order new cabling. I am not sure if Brian sells it or I am going to have to email Skyvision for a quote on 100 feet.

 

[KE4EST]

That wire is not at all good in this application. Your Sensor and servo wires need to be shielded from the motor wiring. Motors are very trashy! They are like a spark gap generator and that noise is transmitted back up the wire like an antenna. With the wires being all together like that, all that noise is induced into the other wires, kinda like the way a transformer works.

As an amateur radio operator imagine if you had a transmit and a receive long-wire installed 1/8" apart and wondering why your receiver front end is overloading.

 

[KE4EST]

This is what you need:
http://www.ebay.com/itm/Commscope-8...224?pt=LH_DefaultDomain_0&hash=item4179927b68

 

[goaliebob99]

That wire is not at all good in this application. Your Sensor and servo wires need to be shielded from the motor wiring. Motors are very trashy! They are like a spark gap generator and that noise is transmitted back up the wire like an antenna. With the wires being all together like that, all that noise is induced into the other wires, kinda like the way a transformer works.

As an amateur radio operator imagine if you had a transmit and a receive long-wire installed 1/8" apart and wondering why your receiver front end is overloading.

I totally understand that and didn't realize the motor is that noisy. I never had issues in the past because I wasn't running a servo. So I guess in hindsight the amount of noise made by the motor really didn't matter then. I do plan on ordering some ribbon cable later on this week. I will run it and report back.