RC10Talk - The Net's Largest Vintage R/C Community

Hello all,
My Rc10 came with an Airtronics Impulse ESC.
I never got it to work properly. It turned on a few times but only worked right once.
I haven't gotten it to turn on in a while.
I put a Novak 17.5 system in my Rc10 last year, but now I'm getting a Traxxas Hawk 2 and it would be cool to get the old ESC I have working for it.
I opened it up and found a fried transistor. Attached are pictures of the whole ESC board and the pitiful remains of the transistor. It had 3 wires going to it, and the place it was attached is circled on the board.
Any idea where I can get a new one?
I have very limited electrical knowledge.
Thanks!

Can I just use any 3 wire bipolar transistor?

Without knowing what part you need, it will be pretty hard to get that working. The new one would need to be the same type as the original. If you can make out any numbers on it, you can try looking at places online. But my guess would be if that blew, something else is wrong as well.

Thanks for the help.
Did you look at the picture of the blown transistor? I can make out a B, and a Q underneath it. I think there was also an R somewhere. Can anyone help me narrow it down? I don't even know what categry of transistor it would be under.
Does anyone else have an old Airtronics esc like mine?
Is this even worth my time?
Why wouldn't a similarly sized but not identical transistor work?

85Edinger wrote: Why wouldn't a similarly sized but not identical transistor work?

It depends on what it's funtion was. My guess with it blown out like that it had to do with voltage. Maybe an accidental polarity arc or something made it pop.

From the pictures that you posted and position in the board it is most likely a voltage regulator not a transistor. If you reversed it you would have blown out a cap for sure. Sometime you can use a substitute modern part but the specs have to be rather close.

Can you post a good photo of both parts of the blown part.

But before you go though a bunch of trouble do a multimeter check of the fet bank. If your fets are gone you may be out of luck.

also had this problem on my Novak 410mxc, when I plug the leads in reverse, the fuse pop but had no more breaks. will try to post some pics....

slow_jun wrote:also had this problem on my Novak 410mxc, when I plug the leads in reverse, the fuse pop but had no more breaks. will try to post some pics....

Unfortunately that speed control look pre reverse protection. Also when ever you reverse any of these old esc's they always blow at least 1 cap. There is no detectable cap damage in those photos.

Hang on, are you saying that I ran it in reverse, blowing the transistor?
Edit: oh, it might be a voltage regulator? I'll keep that in mind.
I sent a message to a guy on ebay with an Impulse ESC asking very nicely for help getting the code on the part, but I'm not expecting much.
Okay, I've done a little research. A voltage reg is a transistor and a diode?
It has a heatsink on the back. My dad says that makes it a power transistor?
Thanks!

85Edinger wrote:Hang on, are you saying that I ran it in reverse, blowing the transistor?

No, I am saying that you did not reverse it. If you reversed it the first thing that blows up 90% of the time is a capacitor. In your pictures there is no capacitor damage that I can see. That does not mean that a capacitor is not bad. The first thing that you should check is the MosFet. There are six of them in your speed control. Make sure that they are still good before you go and start chasing parts that surely obsolete. I have successfully repaired many ESC's. The most common problems are pots and fet's. If either of these are bad it is not always easy to get an equivalent spec part. They have to be a very close match or else it will not work properly or not at all. The voltage regulator is used in the BEC built in the ESC. Most of the time it is used to drop the voltage to something between 4.0 and 6 volts and keep it stable. The function varies with the spec of the speed control. The little bit of metal is a heat sink. Just because it has a heat sink that does not make it a power transistor aka MosFet. There are lots of components that look similar but have completely different functions. Once again you have to have an equivalent part that has a very close spec or else it may not work or burn up something else like your receiver when you plug it in and try to test it.

urban hype wrote:

slow_jun wrote:also had this problem on my Novak 410mxc, when I plug the leads in reverse, the fuse pop but had no more breaks. will try to post some pics....

Unfortunately that speed control look pre reverse protection. Also when ever you reverse any of these old esc's they always blow at least 1 cap. There is no detectable cap damage in those photos.

for mine, one is evident (broken) i'll post some pics later... hope someone can advise a replacement parts for it. when I reversed the pol the brake was gone...

Good news! The guy with an Rc10 and two Airtronics Impulse ESCs says he'll crack one open and tell me what the component says! Fingers crossed. . .

Nice, hope it pans out.

I'd like to try an FET test, but I don't know how. Are there guides available?

85Edinger wrote:I'd like to try an FET test, but I don't know how. Are there guides available?

Here is another thread that I explained how to this test and how to do the repairs.

http://www.rc10talk.com/viewtopic.php?f=78&t=31772