I had to take a day off from posting yesterday. First off, we were wiped out once we got here and set up, and, secondly, I did not want to jump right in to the problem-du-jour again after our brief success with the engine rebuild. Speaking of which, the folks at Infinity Coach, who have been following the saga here on the blog, called me yesterday to discuss the repairs, and have offered a fair and equitable settlement of the portion attributable to the dirt ingestion.

We are back in San Jose visiting family for a few days. As on our last visit, we are staying at the San Jose Elks Lodge (map), which is convenient to both light rail and CalTrain.

When we arrived here, I attempted to deploy our DataStorm internet satellite dish. It elevated, skewed, and began rotating to the correct azimuth, only to stall at about 28 degrees. Several stow-and-deploy attempts yielded the same results. When the azimuth motor stalled around 28 degrees, the degree indicator would immediately jump to 370, and the dish would stop hunting.

I suspected, based on this behavior, that something was physically halting the rotation of the dish. The way the DataStorm dish controller knows that the dish is at the travel limit at either end of any of its three axes, is that the motor current increases as the motor stalls. At some preset current, the controller stops trying to move the dish, and assumes the dish is at the pertinent travel limit. This would explain why, even though the dish had only moved 28 degrees, when the motor began to stall, the controller suddenly indicated 370, the far clockwise travel limit.

Up to the roof I went, screwdriver in hand. After removing the weather cover over the azimuth mount, I removed the azimuth drive motor. This consisted of a small electric motor with an encapsulated gear train, driving an aluminum pinion gear. The pinion travels against a ring gear the entire diameter of the mount. What I found was a bit of plastic stuck in between two teeth on the pinion gear. It was being held there by fairly viscous gear grease.

Removing the plastic allowed the pinion gear to continue its travel around the circle of the ring gear. However, the bit of plastic turned out to be one of the teeth of said ring gear, and, specifically, the tooth at zero azimuth. This makes perfect sense, of course, as the pinion gear exerts extra force on that tooth every time the dish stows, as the motor stalls out against it.

Once I removed the tooth from the pinion gear, the dish could not stow. This is because, as it attempted to return the azimuth to zero, eventually the pinion landed on the now-broken tooth, whereupon the pinion continued to rotate, clicking against the remaining bits of tooth. Since the controller is depending on the motor to stall out, drawing stall current, when the dish reaches zero azimuth, and the controller never sees the current go this high, the controller never stops rotating the azimuth motor.

Unfortunately, the dish must stow (and indicate as properly stowed) before the controller will begin another "find satellite" pass. So the broken tooth on the plastic azimuth ring gear effectively means our DataStorm can not perform its intended function of automatically deploying the dish and finding the satellite.

I was able to get us on-line last night by "manually" positioning the dish using the motor controls. Once the azimuth motor began rotating the dish clockwise, the broken tooth on the stationary ring gear was no longer involved. By using the satellite aiming parameters automatically determined by the program, I was able to point the dish at the satellite well enough for the software to recognize that the dish was approximately aimed at the right bird. Hitting "find satellite" from this point bypasses the need for the dish to stow fully before attempting a pass -- instead, the controller goes right into the "peaking" process, where it fine-tunes the aim and skew, and begins a dialog with the network operations center across the satellite to finish the alignment and go on-line.

Now that we are on-line, we're fine until it comes time to leave. At which point, the "stow dish" command will no longer work, and we will again need to use the manual controls to return the dish to travel position. We will need to stop the azimuth motor just shy of its zero point to avoid the broken tooth. Presumably, we can continue to get on-line and stow by repeating these two processes, but it is very tedious indeed.

After several frantic posts on the DataStorm users group forums, and two calls to MotoSat customer service, I learned that MotoSat will replace the azimuth ring gear at no charge. We just need to send the unit to Salt Lake City, which we will accomplish by driving there.

Some of you may already know that this is a used dish, and we are actually the third owners. It is one of the very earliest DataStorm dishes ever installed, and was initially installed as part of the beta test program. As it turns out, later dishes were fitted with an aluminum ring gear, precisely because of problems with the plastic one such as ours. I suspect our ring gear only lasted until now because neither of the previous two owners really used the dish very much. We've used it daily for six months, and the plastic ring gear just had enough.

On my first call to MotoSat, they had indicated that we would have to cover cost of repairs. After I learned of the plastic-to-aluminum ECO and called them on it, they agreed to cover the repairs. So we'll have our dish fully operational again, but it will cost us a trip to Salt Lake. We're still noodling through whether to head straight there from here, so we can have our dish working ASAP, or hold off until we are en-route from Forth Worth to Oregon and Washington at the beginning of July, when we have to go right through Salt Lake anyway. In which case, we'll have a month or so of manual fiddling with the dish every time we park.

At this point, our plans from here are very much up in the air. We may head back to PEDCO for follow-up, or we may head to Salt Lake for dish repairs, or we may head to Tucson, which is where we were headed (to visit friends) when we first diverted from Phoenix for the engine repairs.

What we know for certain is that we will be here at least until Wednesday, and we need to be in Fort Worth on June 22nd.