Cheap "high voltage" esc Quest

[rschoi_75]

Ok, I just heard back from Modellfun and they offered to replace my esc. Good news. It shows that they are not just a chop shop. However, in the interest of science, I've sold off my esc to Sikeston34m so he can run some experiments on them.

[sikeston34m]

I received the ESC in the mail today. Thanks.

I cut the shrink off and took a look.

The power board looks ok. I haven't removed the heat sink, but I can see the edge of each FET and they look fine. Usually when a FET goes, it makes a mess.

The caps are bulging and the insulation on their leads is almost fried off. There are 2 of them and they are rated at 35v @220uf. These are VERY small IMO. It would do much better with larger ones or at least multiples of these. About 5 of them at least instead of 2.

The Brain board has problems. It smells burnt. I can see one small component that is fried. I will spend some time carefully unsoldering and lifting the power board to discover exactly what the problem is.

Here's what I think. The BEC circuit on the power board is gone. This has dropped power to the brain board. Thus making it "brain dead". LOL

To test this theory, I was hoping it would become functional being powered with an external BEC. No Dice. So the internal BEC isn't even putting out enough power for the Brain to function.

With external BEC power, the brain board heats up quickly. It definately has a BEC problem.

Were you using an External BEC with this on 5S? Or just the built in one?

[snellemin]

On mine I used a Ebec, when it blew. When the brain was taken out there was a mess on some of the chips. It looked burn at first, but it was just nasty flux.

Those caps are small huh. The heatsink just pops right off, as it's just sitting on a thermal pad.

[sikeston34m]

Originally Posted by snellemin

On mine I used a Ebec, when it blew. When the brain was taken out there was a mess on some of the chips. It looked burn at first, but it was just nasty flux.

Those caps are small huh. The heatsink just pops right off, as it's just sitting on a thermal pad.

Yes, these caps are small and overloaded IMO. It's pretty obvious when the power lead insulation melts like this. They were running very hot.

So what blew on yours?

[rschoi_75]

I was running an external bec, which also fried at the same time the esc did. I think it may have been partially my mistake since I forgot to disable the internal bec. whoops.

[sikeston34m]

Originally Posted by rschoi_75

I was running an external bec, which also fried at the same time the esc did. I think it may have been partially my mistake since I forgot to disable the internal bec. whoops.

Hmmmm............

What voltage was your external BEC set at?

[BL_RV0]

hey, do you guys think this esc could work with a large outrunner in my direct drive tmaxx?

[rschoi_75]

6v. its was the koolflight ubec from here.

[sikeston34m]

Ouch!

With the External at 6v and the internal at 5v. This is probably what took them both out.

The external probably went first, then the shearing heat of a 5S battery set in on the internal BEC.

[BL_RV0]

si there a way to disable the internal bec?

[sikeston34m]

Originally Posted by BL_RV0

si there a way to disable the internal bec?

Yes. All you have to do is lift the center "red" wire from the ESC to receiver plug.

[BL_RV0]

just cut it out? and can someone answer my question, will this esc work for my t-maxx on 6s? (large outrunner)

[sikeston34m]

Originally Posted by BL_RV0

just cut it out? and can someone answer my question, will this esc work for my t-maxx on 6s? (large outrunner)

You can either cut it, OR just pull it from the connector and tape it back.

Taping it back makes this easily reversible.

6S with this ESC is probably pushing it. Direct Drive with an outrunner? Hmmmmm............... It might work.

[BL_RV0]

well for $85 and free replacement i dont see why not!

[rschoi_75]

any news on this?

Hey sike... this is off topic, but I just saw a little show on your hometown. Looks nice! They showed the restaurant where the waiters throw dinner rolls at you... looked like fun and good food. It makes me hungry for some chicken fried steak. mmm.....