9920 let out smoke...seems fine? - RC-Monster Forums

lydiasdad · 04:48 PM

I recently grabbed one of the bk 9920's Mike had on sale. I installed it in my rustler with 6s a123 and a 9xl using a receiver pack. When I took it for it's first test run everything was working great, then smoke out of the side where the motor wires come out. I unplugged it immediately to double checked everything. It all looked fine. I plugged it back in and it seems to be working fine. I did some searching and found others had similar problems with smoke leaking out of their bk's. It is not stuttering or acting funny at all. Some people reported that their power was reduced even though the controller still worked. My question is, how do I know if it is reaching full speed? With 6s and a 9xl it could only be at 80% and it would still be crazy fast. Thanks.

aqwut · 11.14.2007, 05:09 PM

maybe a capacitor went on ya....

jokerjustin · 11.14.2007, 07:41 PM

taht or you might have blown a couple fets. its would still run but it would heat up a great deal faster and not be able to transfer all of the current

lydiasdad · 11.14.2007, 08:05 PM

I was actually watching it when it smoked. The smoke came from the opposite side of the caps. Any way of knowing for sure it's putting out full power besides switching out esc's and comparing?

squeeforever · 11.14.2007, 08:11 PM

Are you using a UBEC?

lydiasdad · 11.14.2007, 08:16 PM

Im using a battery pack. Yes, the black jumper is removed.

kulangflow · 11.14.2007, 09:48 PM

Interesting .. I had the same thing happen to mine. It was on my first use too, but I was only using 4s lipo. It smoked after 10 minutes. I didn't think to try it after it let the smoke out though. Too scared. Now I just need to get ahold of BK and see if it's worth going through the warranty process.

Good luck with yours!

kulangflow · 01.21.2008, 11:22 AM

Quote:

Originally Posted by kulangflow

Now I just need to get ahold of BK and see if it's worth going through the warranty process.

Quick follow-up:

BK did warranty my 9920 with no fighting necessary. Irene Becker handled the claim. I got it back one day shy of two months. That's a long time, but a lot better than the 6 months I had heard about in the past.

The funny part is that I had forgotten about it by the time it arrived on my doorstep. I guess I had mentally written it off, so it was a fun surprise to have it back.

lydiasdad · 01.21.2008, 01:22 PM

Quote:

Originally Posted by kulangflow

Quick follow-up:

BK did warranty my 9920 with no fighting necessary. Irene Becker handled the claim. I got it back one day shy of two months. That's a long time, but a lot better than the 6 months I had heard about in the past.

The funny part is that I had forgotten about it by the time it arrived on my doorstep. I guess I had mentally written it off, so it was a fun surprise to have it back.

Thats great news! I have several runs on mine now and it's still working fine. (knock on wood)

I haven't been pushing it real hard though, only pulling 66 amp spikes with my current setup.

sleebus.jones · 11.16.2007, 10:25 AM

Quote:

Originally Posted by lydiasdad

Im using a battery pack. Yes, the black jumper is removed.

Can you send me a pic of where that dang black jumper is? I looked all over and I must be an idiot because I can't find it.

ObOnTopic: I'm running one of those "selloff" 9920's with 18 cells. I pulled the red wire on mine, (see above problem) and I've had no problem. I know I've run it past 25v, wasn't thinking about full pack charge voltage. I don't know what a fully charged a123 is, but I think you should still be under the max voltage.

Sleeb

01.21.2008, 12:07 PM

Quote:

Originally Posted by sleebus.jones

Can you send me a pic of where that dang black jumper is? I looked all over and I must be an idiot because I can't find it.

ObOnTopic: I'm running one of those "selloff" 9920's with 18 cells. I pulled the red wire on mine, (see above problem) and I've had no problem. I know I've run it past 25v, wasn't thinking about full pack charge voltage. I don't know what a fully charged a123 is, but I think you should still be under the max voltage.

Sleeb

the black jumper is near the red programming jumper, but further back under the shrink wrap.

J.

jokerjustin · 11.15.2007, 11:11 AM

well that may be your problem... the red wire is the one that you need to diconnect...or is that only in the mamba max?

kulangflow · 11.15.2007, 11:29 AM

With the BK controllers, pulling the black jumper disables the BEC. You also have the option to pull the BEC wire.

sapper_triple6 · 11.15.2007, 02:11 PM

Mine did the same thing. I sent it to BK and they said it was the fets.

Serum · 11.15.2007, 02:29 PM

My guess is some of the fetts went bad.

it happens with larger arrays of FETTS, it can work for years..