NEW MOTOR DOA??

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MikeinBaja

SatelliteGuys Pro
Original poster
Sep 9, 2008
869
15
San Diego area (CA)
Finally taking some time to get the SG9120B motor project going. Mounted the dish on my test stand - tuned in my true south (SM5) with good S & Q on both the Birdog and direct to receiver.

Shut everything down - connected LNB to LNB in on motor - reciever to receiver outlet on the motor. Power everything up. No S or Q! Recheck connections - all right and tight. No light at all on the motor. Went through DiSEq settings on receiver - nothing.

No motor light, no movement with the manual button.

Reconnected straight line from LNB to receiver - works fine.

Did I miss something or is this motor DOA?
 
Got all the satellites set up with motor control also? A couple of my receivers you have to activate motor control and pick USALS or Diseqc, in one menu, set your latitude,etc. Then under each satellite entry again you have to activate motor control . Just a thought...
 
Got all the satellites set up with motor control also? A couple of my receivers you have to activate motor control and pick USALS or Diseqc, in one menu, set your latitude,etc. Then under each satellite entry again you have to activate motor control . Just a thought...

Did all that - nada. Not getting a signal through the motor at all, but when I put a barrel in line & bypass the motor - good S&Q. No lights or power at the motor.

I think it's DOA.
 
Finally taking some time to get the SG9120B motor project going. Mounted the dish on my test stand - tuned in my true south (SM5) with good S & Q on both the Birdog and direct to receiver.

Shut everything down - connected LNB to LNB in on motor - reciever to receiver outlet on the motor. Power everything up. No S or Q! Recheck connections - all right and tight. No light at all on the motor. Went through DiSEq settings on receiver - nothing.

No motor light, no movement with the manual button.

Reconnected straight line from LNB to receiver - works fine.

Did I miss something or is this motor DOA?

Did all that - nada. Not getting a signal through the motor at all, but when I put a barrel in line & bypass the motor - good S&Q. No lights or power at the motor.

I think it's DOA.

Mike,

You pretty much nailed it. It is obvious that the motor is defective right off. It may be a very simple problem, but since it is brand new, I wouldn't mess with it.

Since it is NOT even passing the signal from the LNBF, and the motor LEDs are not illuminating, I would say that the electrical connection at the "FROM RECEIVER" port on the motor is broken. It could be a simple thing to repair. A bad solder joint or a solder joint that simply never got wetted with solder at all. There are some older SG2100 motors that had poor quality solder connections at the F-connectors to the circuit board inside. These usually witnessed some time in the field for the poor quality solder connection to start displaying itself. Yours may have never even seen solder! Oops.

But, like I said, don't bother with it as it could be something worse, like a cracked or broken PC board. Take advantage of the seller's warranty (or mfgs warranty) and get a good one. No need starting out in the hole.

RADAR
 
I have a sg2100, if I connect the single line from receiver to motor, nothing more, my LED works, I would imagine this should be true with your model as well. If you have a volt meter, might want to check voltage on receiver, make sure it is correct as well, depending on your stb?
 
Radar, last weekend I got a chance to fix my spare 2100 with just the solder joint problem you described..oh what fun. Word to the wise on these motors hand tighten the coax to the fitting on the motor...if you get it stuck..the whole fitting comes out in your hand...Blind
 
I'm not disagreeing with the diagnosis above, but...
- could ya state for the records, what receiver you are using?
- could you try another receiver?
- can you test the LNB voltage with the motor between it and the receiver?

I'm thinking...
- the motor could simply be shorted
- the receiver's regulator could be overloaded
- some brand/model FTA receivers never really worked a motor, even though they were supposed to.
 
Radar, last weekend I got a chance to fix my spare 2100 with just the solder joint problem you described..oh what fun. Word to the wise on these motors hand tighten the coax to the fitting on the motor...if you get it stuck..the whole fitting comes out in your hand...Blind

I hear that! If for some reason the cable connector binds on the threads, stop and get two 7/16" wrenches and hold the F-connector on the motor from turning. It may be beneficial to take one of your wrenches and grind it thinner to have more clearance to fit better (so that there is more clearance between the cable connector and the hex nut on the female part of the F-connector on the motor housing). If there isn't a hex "nut" on the connector, use a needle nose vice grip or something to hold it below the used portion of the threads - but don't clamp it too tight. You just don't want that connector to twist and start spinning and break the soldered electrical connection inside.

I had a cable connector on one of my motors that evidentally had become a bit oxidized or had some grit or wasn't perfectly threaded and although I had only tightened it finger tight, it was much more difficult to remove than that. I noticed the F-connector on the motor start to turn on me (maybe a 1/16 of a turn) and I stopped myself before doing any harm and applied two wrenches to remove it before causing any damage.

It is always a good thing to apply some dielectric grease to the threads and the center conductor as well. This keeps the threads from seizing or fretting together and deters oxidation. It is also a good idea to occasionally unscrew your connectors and put them back on throughout the year, especially if you are in a salt water or moisture prone environment. Reapply the brease when you do. Even with finger tightening the cables, you will find that they seize eventually due to corrosion and oxidation. Not to mention that two metals in that close proximity will eventually fuse or weld themselves together, as the metals eventually bond on a molecular scale. Each metal piece can actually start sharing the molecules on the surface. The two migrate together and are basically welded together.

RADAR
 
I'm not disagreeing with the diagnosis above, but...
- could ya state for the records, what receiver you are using?
- could you try another receiver?
- can you test the LNB voltage with the motor between it and the receiver?

I'm thinking...
- the motor could simply be shorted
- the receiver's regulator could be overloaded
- some brand/model FTA receivers never really worked a motor, even though they were supposed to.

Anole,

I agree with your further options for the problem.

Well, not the shorted motor part, though... Not without exhibiting some other behaviors indicative of an overcurrent shut down that would be detected by the overal box operation. Like a continually rebooting receiver. But, that would also have to be a dead or direct short, and still a problem with his new motor.

Furthermore, since the motor isn't moving off target, it should still pass the sat signal from the LNBF regardless of the motor/receiver compatibility. Unless, as you state, it is actually shorted, which is killing ALL the signals. Then, it would be back to my previous statement about overcurrent shutdowns and rebooting.

The short circuit protection operation depends upon the individual receiver, of course. If there is a circuit that protects just that area of output alone, and not the overall unit, then you might not notice any other indications. A highly expensive receiver might offer this kind of protection (and still keep the other areas of the box powered). But, all my boxes usually shut the main power supply for the whole box down and then seems to come back up to recheck if the overload condition has gone. Thus leading to the repeated rebooting of the box.

RADAR
 
I'm not disagreeing with the diagnosis above, but...
- could ya state for the records, what receiver you are using?
- could you try another receiver?
- can you test the LNB voltage with the motor between it and the receiver?

I'm thinking...
- the motor could simply be shorted
- the receiver's regulator could be overloaded
- some brand/model FTA receivers never really worked a motor, even though they were supposed to.

I tried with 2 different receivers - CS6000 and GeosatPro DSR200C (which is 1.2 Disqc). Neither would see any Q or S when run through the motor - but both showed good SM5 numbers when I took the motor out of the loop with a connector. Used the Geosat to start - pulled out the CS when I ran into problems. Even changed to a different mfg LNB - no change.

Can't run a voltmeter on the motor - took it down this afternoon and boxed it up - they are sending a replacement :) Not sure there ever was any voltage though - never got any lights on the motor at all.
 
Short follow up - whatever is going on with the motor - it fried the LNB.

Took the motor off this afternoon & moved the dish back to AlJaz - LNB was toast. Changed it out with a spare and all was good.

Can a shorted motor fry an LNB??????????????
 
Short follow up - whatever is going on with the motor - it fried the LNB.

Took the motor off this afternoon & moved the dish back to AlJaz - LNB was toast. Changed it out with a spare and all was good.

Can a shorted motor fry an LNB??????????????

Mike,

No. An open (or shorted) motor connection wouldn't harm the LNBF. That would have simply taken the LNBF out of the circuit. There has to be another reason.

I don't know what could have caused this problem. It is awfully coincidental, but I cannot see a logical connection between the two. Unless you had an electrical storm that got to both the new motor and the LNBF? If you experienced such a storm recently, I would be monitoring the receiver for damage, too. Rare time of year to have an electrical storm, but anything is possible.

RADAR
 
Have you checked the SAT IN port on both receivers for correct voltage? 13vdc -vertical / 18vdc - Horizontal (+/- 10%).

There was a thread a few months ago that members mentioned a particular brand / model LNBF with high failure rates when used with a motor. Thought it was strange, as one normally does not associate LNBF failures to electrical influences associated with motors.
 
Have you checked the SAT IN port on both receivers for correct voltage? 13vdc -vertical / 18vdc - Horizontal (+/- 10%).

There was a thread a few months ago that members mentioned a particular brand / model LNBF with high failure rates when used with a motor. Thought it was strange, as one normally does not associate LNBF failures to electrical influences associated with motors.

Brian,

Have you ever been witness to a receiver, any receiver, that output a detrimental AC signal on the LNBF line that could possibly damage both a motor and an LNBF, without showing symptoms of a problem on the receiver itself? I have not, but I was just curious... I haven't seen or heard of every failure yet. So, unless some external power was at hand, such as lightning, I cannot fathom anything that seems reasonable to cause Mike's motor and LNBF failure other than just pure coincidence.

RADAR
 
Oh, I guess I can think of one failure that might explain this... It is the receivers output for control of the motor and LNBF. This would explain it. The output voltage and power is too weak and borderline to operate the motor. It dies, but the receiver itself isn't shutting down for an overcurrent fault. The receiver doesn't detect such the failure as the current limiting circuit isn't tripping out, but it still isn't enough to drive the motor or the LNBF. It is borderline failure. The power circuit for the motor and LNBF within the receiever was weak and it would operate the LNBF alone, but when the motor was installed, it couldn't supply enough power. The overcurrent protection circuit did not kick in because the problem may be ahead of that circuit, it didn't realize that there was an overload, it was actually an "underload" or an "undersupply"???

Mike, if you experience the same troubles with a new motor and your current LNBF, you should check your cable first and then start looking at the receiver. Do yoiu have an additional receiver to play with? If the problem arises again, swap out the receiver.

If you are adept at electonics, you could also make up a tap in your line so that you can put a voltmeter and even an ammeter branch circuit to check this. You can do this without degrading the signal quality coming in too much. That would tell us a lot, if you can do it.

RADAR
 
We have benched many receivers with voltages present on the SAT IN port that could easily damage an LNB. The Fortec Star Lifetime Ultra receivers often output 30+ volts when the power supply fails.
 
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