Bad BLS251?

[flymustangs]

Can I get someone to verify my troubleshooting? I was just spooling up my Logo 5003D this afternoon and as soon as it got a little headspeed it started to piro. Throttle hold and no damage. When I checked it I had no tail servo control. I have the DS760 and a BLS251. I can move the servo by hand, but it does give resistance at one endpoint. It will also reposition when the receiver is powered on if it's set at one endpoint. Then I can move it freely again. I verified the rudder channel on the receiver with a standard servo. I also plugged a S9252 that I had into the DS760 (after changing the servo type accordingly). It works as well. I have a new DS760 that's going into a TREX500 that I'm building. I guess I could hook the BLS251 up to it for a test, but is there any point? It looks like the servo is bad to me. I only found one other mention of a BLS251 failing here so I guess I'm one of the lucky two. At least it didn't result any any damage.

Thanks.
Ken

[flymustangs]

I went ahead and tried the new DS760 and got the same symptoms as I expected. Of course there is no warranty on the BLS251 because I got it off ebay. I'm reluctant to get another one. Having a servo fail while walking out to the flight line is not a good thing. Any suggestions on a different tail servo?

Thanks.

[BruceW]

Are you sure you set it up with the right timing on the DS760? The BLS251, S9251, S9256, and Logictech 6100G have a frame rate of 760us at 333Hz which is much shorter than all the other servos at 1520us. I think if it gets setup with one of the other modes it will jitter around but not drive.

I've had good results with my BLS251 as well as others on here but its definitely possible to get a bad one. Its also the preferred servo when running V-stabi.

[flymustangs]

I'm sure it was set correctly. The heli was flying fine. It looks like the servo literally failed from the bench out to the flight line. The S9252 has a different timing, which I set before trying it. I also had the gyro configuration saved for the BLS251 and loaded it into both gyros and got the same symptoms. Both gyros run the S9252 just fine with the appropriate timing set. I saw one other post from Shawn where he had a BLS251 fail in flight. I guess two failures isn't that bad. Maybe I will get another one and just buy it from a retailer so I get the warranty.

Thanks.
Ken

[BruceW]

Well I guess a bad one can show up every so often. I would still try to reach Futaba and see if they will repair it though.

[flymustangs]

Thanks. I'll do that. Anyone know what they charge if it's not covered under warranty? All I could find was a $15 charge for a "checkout".

[BarracudaHockey]

If it came from China/Hong Kong/ or whatever they probably wont fool with it.

[flymustangs]

What about this servo for the tail? It looks like it's used quite a bit for cyclic and some have used it for the tail. I think I only found one negative comment with using it on the tail. It's almost as fast as the BLS251 and it will run on 6V, not that it matters right now because I'm using the BEC on the Jazz 80 that's only 5V. That also made me wonder if that contributed to the failure of the BLS251. I wonder if the BEC on the Jazz is running a little high and the BLS251 couldn't handle it. I'll have to check that.

Thanks.
Ken