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-   -   Cheap "high voltage" esc Quest (https://www.rc-monster.com/forum/showthread.php?t=9624)

rschoi_75 02.05.2008 12:26 PM

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 02.09.2008 01:52 PM

I received the ESC in the mail today. Thanks. :yes:

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 02.09.2008 01:57 PM

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 02.09.2008 02:05 PM

Quote:

Originally Posted by snellemin (Post 147979)
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 02.09.2008 02:11 PM

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 02.09.2008 02:13 PM

Quote:

Originally Posted by rschoi_75 (Post 147982)
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 02.09.2008 04:40 PM

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

rschoi_75 02.09.2008 05:08 PM

6v. its was the koolflight ubec from here.

sikeston34m 02.09.2008 05:45 PM

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 02.09.2008 05:58 PM

si there a way to disable the internal bec?

sikeston34m 02.09.2008 06:00 PM

Quote:

Originally Posted by BL_RV0 (Post 148028)
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 02.09.2008 06:04 PM

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

sikeston34m 02.09.2008 06:07 PM

Quote:

Originally Posted by BL_RV0 (Post 148031)
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 02.09.2008 07:26 PM

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

rschoi_75 02.20.2008 07:25 PM

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.....


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