cracker39

I emailed the place where I bought the boat online but haven't gotten a reply yet. Here's my problem.

After I finally got batteries and installed them, I found that my sail winch servo isn't working properly and I'm afraid to try to sail it. I set up my RX battery pack and radio transmitter with 12 new NIMHrechargeable AA batteries that I ran through a discharge and charge cycle four at a time, with my Triton field charger, using a batter holder I bought at Radio Shack. When tested four at a time after the charge cycle, I got a 5.4V reading, normal full charge for this type of battery.

When the switches are turned on (radio 1st, then receiver as I always do) the sail servo has a buzzing noise in most positions. My experience with servos is that buzzing unsually occurs when a servo arm is positioned too far in one direction or the other, not throughout the entire movement range as mine is doing. At full down or full up, it buzzes continuously and in other positions, it buzzes intermittantly, less when centered.

Then, MORE IMPORTANTLY, the servo tends to "freeze" up and refuse to move at all, mostly in the full down stick position. This occurs with or without a slight pressure is on the sail (as if wind were pushing on the sail). It mostly sticks when the sail is fully retracted, but sometimes it freezes when the sail is in the center positon and no pressure is on the sheets. When the servo is fully retracted, the main and jib sheets are not fully tightened, so they are not restricting the servo movement. This freezing problem occurred before I even connected the sheets to the sail booms. When it does freeze up, I usually have to nudge the arm to get it to move again.

I thought it might be the battery voltage, so I changed the RX NIMHs for four fresh Enegerizer alkilines for the full 6 bolts, but it still has the same servo problem. Any suggestions as to cause of this problem and a fix?

mfr02

If you swap the steering servo connection with the sail servo and check behaviour, this should indicate whether there is a problem with the radio channel or the servo.
Assuming the problem stays with the servo, its a broken one, and the best cure is replacement.
I have had a fault in one servo affect the power, and give problems elsewhere, but that was a one-off in the last twenty years.

cracker39

Question for anyone with a Nirvanna II. My receiver is in some type of shrink wrap and the wires are coated with some type of caulking where they come out of the wrap. Does the receiver have plug in connectors for the servos inside the wrap or is it all hard wired?

LtDoc

Dale,
I've never had my hands on a 'Nirvana' so honestly can't say anything about them for sure. Having said that, I can say that your description of the receiver means it is not a 'standard' off-the-shelf type of thingy, sounds like a very proprietary type thingy. Beats me.
A 'standard', 'normal' R/C receiver has two or more 'slots' where servos can be plugged into it. Also, usually at least one more 'slot' for the battery/power. If it's covered with 'shrink-wrap' and has some kind of 'goop' sealing the ends, it sounds like it's probably water-proof, which ain't bad. That 'water-proofing' can also be not such a good thing, as you are finding out. (The typical R/C radio system is very, very seldom water-proof, that's up to the user to 'fix' if necessary.)
Part substitution is one method of finding the bad part. Not always the easiest method since you may not have something to substitute or be able to do that substituting if you had the thing (very common though).
I think your best bet, all things considered, is to contact whoever you bought the thing from, see what they have to say.
- 'Doc

(sounds like the servo, but not making anyu bets on it.)

Bilge_Snipe

Dale, it sounds like you may have purchased the Ready to Run Nirvana that MegaTech distributes. They have been known in installing weak servos on their sails. They even have springs on the sail arm to keep from stripping their servos. Sometimes these springs pop off or fall off. Now http://sailrc.com/ where I purchased my Nirvana installs better servos and modifies the sail arm, to do away with the springs and stripping problems. The boat is a real good sailing boat, once the problems are corrected. I hope you resolve your problems so you can enjoy her.

cracker39

I did buy it from SailRC.com. It has no springs on the sheets. I'm familiar with RX equipment as I have some RX planes. I'm pretty sure that under the shrink wrap, my TX has connectors, but I don't want to start removing parts and checking them until I hear from SailRC about my problem. My boat is a "rigional", so it may not have any of the mods that SailRC makes. If the upload works, here's a picture of my electronics.

Bilge_Snipe

Dale, I talked to Steve last week, he's in the process of moving his business, but his new phone number is:

303-955-2784

He should be able to resolve your problem or let you know how to correct it yourself.

Good luck,

hiljoball

Hi Dale, and other Nirvana owners.

When I look at the sail servo installation, it looks as though there will be a lot of pressure on the arm at close hauled.

I would try to turn the servo around and then reseat the arm to be in line with the case at close hauled. Now, at close hauled there would be no force acting on the servo electronics as the load would be in column with the arm and the case. This would reduce the servo load and prolong battery life and gearing. This arrangement also gives the effect of fine tuning at close hauled as the amount of sail movement is smaller for each move of the transmitter lever.

cracker39

John, I'm not sure I understand what you are telling me. The servo could only be turned 180 degrees and the arm would still be in the same relative position as it would have to be placed back in the same position relative to the cockpit. The servo can't be turned 90 degrees as it has only one area. I reposted the original photo below showing the arm in close haul position on the left, then the next photo is with the arm fully extended (stick full up) to let the sails out. Due to the cockpit design, everything is in it's place and cannot be repositioned. In the 2nd photo, the battery pack is in place where it was out of the cockpit when I took the first photo.

hiljoball

Hi Dale,

What I am suggesting is to bring the servo to close hauled. Then remove the servo arm. Then turn the servo 180 degrees. Now the shaft is further away from the port side of the box. Now, if ithere is enough room, place the arm on the shaft so that the arm in perpendicular to the axis of the servo (when the servo is closehauled).

That puts the highest load (closehauled) in column with the servo shaft, so there is zero torque on the servo.

cracker39

OK John, now I understand. My problem with that is that the boat is new and I need to hear from Steve first before I go messing around with it, although doing what you suggest would take little work and would tell me it that's the problem.

Later.....

I did as you suggested and worked the servo for several minutes with no freezing. It still buzzes slightly at either end of the arm movement, but not as badly as before. Reversing the servo caused a slight, but fixable problem.

The servo arm cannot be adjusted on the servo as it has two tiny springs and two slots that fit onto two protusions on the servo shaft, so it has to go in the prescribed postion. Now that the servo shaft is closer to the starboard side of the cockpit, the servo arm hits the side when fully extended in that direction. The fine tuning on the TX won't take out enough to keep it from hitting the side. So, if I keep the servo in this position, I'll have to put a restrictive device on my TX so that the stick cannot be moved up all the way. This can be done easily enough by taping a little piece of lite ply above the stick, restricting it's upward movement.

Meanwhile, I'll get in touch with Steve to see what he has to say. Maybe in the meanwhile, I'll put the servo back as it was to see if the problem reoccurs. Thanks for the suggestion.

cracker39

I phoned Steve and found out that due to a lot of problems, Megatech has a new sail servo that is more dependable than the one in my boat. I'm calling them tomorrow to see if they will send me a replacement servo. With the sail servo out of the boat, when I hold it and operate the TX, I can feel a very heavy and irregulat grinding inside. It feels like the gearing is stripping, so I'm convinced that it is a bad servo.