Help with electronics issue
 

I put the stock Losi Speed T brushless setup and radio in my SC10. Last time I put it away it was working fine, but when I took it to the track this weekend it started not running correctly. It would roll under power for about 30 feet, then stop and become unresponsive to throttle input, then moments later start working again for another 30 feet, repeat. This was true on flat ground, not necessarily only when jumping. Steering remained operational. The problem seems most noticable in forward, and when it happened, it seemed I could still use reverse OK. But I never did try to run the truck in reverse for more than a foot or two.

Things I checked include:

-- Rebind RX and TX
-- replace batteries in the radio
-- use another batter in the car
-- reprogramed the ESC several times using the software on my laptop
-- checked all wires and solder connections

Putting the stock SC10 motor and ESC back in was something I wasn't really happy to do. I wasn't able to get the Losi RX and TX to work at all with the SC10 ESC. So the issue may be in the receiver, maybe.

Any ideas?

ben

I had a Losi DT which came with the 2.4Ghz Rx and tx.....range issues, runaways in empty parking lots, big headache.

Replaced it with a Spektrum DX2.0 system and no more problems.

Not saying that IS your problem, just telling you what fixed ours.

What kind of battery are you running in the truck? You never mentioned anything about the truck's battery. Could it be a lipo cut-off or something like that?

Are you running your new LiFe batts in this?

If you are, sounds like you are using lipo lvc - I would set it off or at no more than 2v/cell. I run my a123s flat like NiMhs and haven't seen any probs. I run them flat in my Dewalt cordless drill and in 10yrs haven't seen a prob.

I thought about the Lipo cutoff. Put in two different Nimh packs after setting the program to Nimh and no cutoff, and it was still doing it.

Weird thing is last night I got the itch to take another look. Setup everything on the bench and reprogrammed the ESC to the Radio as well. It all seemed to be working fine. So I put everything back in the truck and it is working fine now, ripping up and down the street without issue. I'm really baffled by this...

Only thing I can think of is possibly the gear mesh was hosed. My reasoning for this is I took everything out of the truck when it wasn't working. It worked fine on the bench, then it worked fine when I reinstalled everything in the truck.

ben

I don't like probs like that - you never understand what was going on or what 'fixed' it.

I'd worry it would come back when least expected. Hopefully, you won't ever experience it again.

What purpose does the external capacitor play on the ESC? Reason I ask this is I was considering removing it and resoldering the connections. The positive lead came off once a while back and I repaired it at the track, but wasn't really that happy with the quality of the solder job. The negative lead is still attached as it was from the factory, but looks like it could use a resolder as well.

Any chance this is the culprit?

ben

Thats poss - cap is there to help smooth amp spikes due to servo amp draw. If your setup is tight on amps and the cap is helping, its poss you've found the prob.

Sounds like typical Losi electronics. I've had nothing but crappy ESC from them. They've had to send me replacements on every Losi speedo I've had.

I'm not the first owner of this ESC or motor, but it has been reliable up until now. If the problem continues, I'll replace the ESC and hope that the motor still has usable life left in it.

ben