120 SR main motor problems

sonomadiver · Fully Charged Joined: 08 Feb 2011 Posts: 4

I have a pretty new 120 SR (about a month old). I'm new, so I'm still learning the basics of flight. Today the main motor started to rapidly switch on and off during flight. At first it was almost like a "sputter", but eventually it would stop altogether. I know it's not a battery issue because I was flying on a fresh battery; also, the tail rotor would still spin (once the bird was on the ground or in my hand).

Thinking it was the motor, I went to my LHS and got a new one (I'm lucky to have a great shop in town). But the problem is still there. I also tried it with a new DX6i that I picked up today, but the problem was still there.

Is the 5-in-1 receiver going out on me? Any other ideas?

Thanks!

- larry

tombo242 · Posted: Wed Feb 09, 2011 12:32 am Post subject:

Sounds very like a 5-in-1 problem to me. Evil or Very Mad

Tom.

sonomadiver · Fully Charged Joined: 08 Feb 2011 Posts: 4

Thanks, Tom. I have a feeling you're right. Sad

I've replaced nearly everything on my 120 SR since I got it (primarily due to crashing). Perhaps the 5-in-1 is next on my list.

tombo242 · Posted: Wed Feb 09, 2011 3:18 am Post subject:

Keep us posted on how it goes, always good to know the outcome of these problems.

Tom.

sonomadiver · Fully Charged Joined: 08 Feb 2011 Posts: 4

As it turns out, it was the 5-in-1 board on my 120 SR. I took it to my LHS, where they replaced the card and gave it a quick test flight, all for no charge (they'll send the card back to Horizon).

One other thing I don't think I mentioned: I thought the problem was just a loose solder connection of the main motor to the board. So I pressed my finger against that connection to see if that would make a difference when I spun up the bird. It didn't take long for that connection to get very hot. That would explain why everything would be fine at first, then - eventually - shut down.

I'm back in the air!

PS: If it's okay to say... my LHS is fantastic: R/C Country in Sacramento.

Dumb Thumbs · Posted: Wed Feb 09, 2011 8:21 am Post subject:

Ain't it great to have a good old fashion "brick & mortar" hobby shop to run to for help. I hanen't been to mine LHS lately as the weather has been so bad that flying/crashing is out of the question. Think I'll go this weekend and pre order a Blade mCP X and pick up a couple LiPo's for the rex 450's.