They are working now :).

bump.

first, AAngel pm'd me asking the weight. truck weighs 7.5lbs RTR on a bathroom scale, with buggy tires on it.. give or take 3lbs because bathroom scales aren't very accurate for weighing light stuff =\. not sure how much more w/ MT tires. 1lb? sorry for the delayed reply AAngel.

second. I figured out the problem with the batteries.. while taking my parallel adapter apart today at work, I found one of the battery wires ripped off of the Deans plug. I'm not sure how it didn't short, and not sure how it broke off.. the solder tab on the plug was bent down at a 45 degree angle, so it hit something very hard.. with electrical tape holding it in place, I'm guessing it was making contact only intermittently. I'm have no idea when it happened, but The packs had different charges after my day of racing.. and then I had run it again at work for a minute or two, and checked w/ the DMM, and sure enough, one pack was 20.5v, while the other was 20.7v.
That's all fixed now, and I also added in another plug and a SPST switch for two 12v fans, that will be running at ~9-10v each. One for the motor, and one for the controller. Here's a simple diagram of my wiring setup:
(once small change. I attached the Deans connector for the fans BEFORE the Quark's Deans plug, that way, I can unplug the controller, and still run the fans to cool the controller/motor, if needed.
http://img292.imageshack.us/img292/4...ematicshn0.jpg

and last, I opened up the Quark to see what I had blown. I can't take the controller out of the case, but on the bottom of the lower PCB, between the battery positive lead and the rows of FETs, there's a small component that blew. The case is black w/ smoke directly below it.. Here, look at this picture:
http://img409.imageshack.us/img409/3...mponentav1.jpg

I'm wondering if that could have fried from the one battery making contact on and off.. sudden extra burst of power? the packs aren't in series though, so I'm not sure.. more importantly, how important is this component? I could try and cut a hole in the bottom of the case, and replace the component myself, but metal shavings would be EVERYWHERE, and don't think I'd want to risk it.. depending on how important it is of course..
the component did NOT short out, and is completely unrelated to the shim/epoxy/case modification.
I've got pictures of it fried if needed, but they're on my girlfriend's camera, and she doesn't have computer access ATM.

Also, w/ only one battery being run in this truck, I'm suprised that the packs haven't given me any problems, because they're only rated for 40A constant, per pack. I need to run it for a while ~30min, and see how much of the packs have drained, as I have NO idea how many amps my setup pulls..

ALSO, what's your opinion on this.. I don't have any extra money right now, and seeing as the Neu 1515s are $280, how do you think a Feigao 9 or 10XL would work for the time being? I know they're not as efficient, or powerful as the Neus, but I'd just like to keep the temperatures down, and I can't gear my 1512 up anymore than 14/46.

I'm hoping the fans, and going to the 46t diff will help a little this weekend, we'll see.
I might be bashing tommorow, and racing for sure on Sunday.. my buggy tires are completely bald, and just don't have enough grip on pavement, where we run.. and I'm afraid of using MT tires, because of the heat..
wish me luck.

K, that thing you are pointing at is a small capacitor, ceramic surface mount type. They are probably meant to absorb high frequency EMI in the power stage. I don't think they are absolutely critical to operation, but i'm sure it takes a load off the other caps, and the FET's maybe. (high frequency is hard on components)

Don't even try replace it though. Are you sure it didn't short out on the Quark case? Unless it's a dud, which is very very rare for these types of components, these caps are made by the billions each year.

Oh, and that pick, you CAN'T unplug the controller without unplugging your fans...

LOOKS LIKE TANTALUM CAP and they do fail very frequently with fatal shorts.
This cap need to be replaced with proper one otherwise you will stress other components.

Based on Quark's operational voltage and caps size I will guess 1uF to 4.7uF value with 35V. Check www.digikey.com for good LOW ESR Tantalum replacement. If You have better picture then you shoud be able to read something like 4u7 or 3u3 ...

I was going to suggest checking with digikey for a replacement too. It actually looks like it would be pretty easy to replace too. Just don't try to go hacking on it with a radio shack stick iron. You'll want to use a good soldering station with a small chisel tip. If you know someone with a nice Hakko or Metcal or something like that, it won't take long to do.

Of course, all of this is assuming that nothing else cooked.

What are you talking about, that is a CERAMIC capacitor, not a tantalum. Tantulum's are black with lettering on them usually. Who said a short wouldn't kill them?

You should figure out how much work this will be, and if you need to buy anything expensive such a good soldering station and decide whether it's worth it. Or get a hold of S&T to see if they can help?

Replacing this thing will be no easy task, your circuit is permanently attatched to the case...

zero, you're coming off mighty harsh there. We're just trying to help the guy out. As you said, the circuit is permanently attached to the case and he's pretty much screwed. We all know that it's not going to be covered by warranty and who knows what S&T will want to fix it, if at all.

I'm no electronics engineer, but from what I see, it's just a surface mount component and looks to be a $2 part. If he can source it, why shouldn't he try to fix it. I don't think that anyone said anything about buying an expensive soldering station.

Heck, like I said, with the esc being all glued together and everything, he's pretty much screwed. I have a Metcal MX500 station, I'd be willing to give it a try, provided that he can get a replacement part. As I said, I'm no electronics wiz, but I've soldered everything from battery packs to 0603 resistors that my old eyes need a stereo microscope to see.

Why do you think I'm being harsh man?:eek: GriffinRU seems to know his stuff, but I don't know why he called it Tantalum cap.

The cost of the part is almost nothing, probably like 50 cents about?

Do you think you could get the side off the case, as you DID attach it with adhesive right? You might be able to break it. Then the cap should be in plain view. If you have good nerves, then go for it.

I really don't know why they don't have more than just one of these caps there?

It could be just a high frequency filter judging by the size and placement...

soo.... wouldn't that just be a cap then? :032:

Mine is actually sitting high up, like the person who solders them doesn't do it properly.

Zero, I don't know. It just seemed to me that you were coming off kind of harsh. Since I really don't know what I'm talking about with these things, I'd just like to know if the part is replaceable.

A4, can you shoot a pic of a sideview so that I can get a better look at what replacing the part would entail? I mean, if it is an SMT component, I should be able to do what is necessary from one side of the board, shouldn't I? How much clearance is there between the boards?

Well, it probably is just a cap. But it has to have a small value due to the physical size - that's why I said it was for something like low level RF-like filtering. I suppose it could be a resistor or diode, but it doesn't look like it.

As to the solder job, it was either an addendum (therefore soldered by a person), or the traces it attaches to are big enough where the wave solder couldn't grab (acting like a heat sink).

Yah, we figured it was for low RF filtering. The solder job on mine was kinda bad, it was crooked both ways, up and to the side. Personally, i would have designed it so that the little cap was right up there next to the FET's.

AAngel, do you mean between the power board and control board? I think there should be enough for a tip to get in there, and you can see everything fine.

A4, how can you even see down there anyways? Are you sure it is this component that is fried? Seems to me that you wouldn't be able to directly see it? Am I wrong?

If we can determine exactly what it was that fried and it's near the edge of the boards, I do have a 1.5mm 600* chisel tip at a 45* angle that should get in there pretty easily.

I thought that we were talking about that little yellow/orange part that is circled in the pic. Are we talking about something that is between the boards?

IMO, that smoke residue isn't from that cap unless the end of it is blown off or it's cracked in the middle. Zero is right though, it looks like a little ceramic cap to me, probably an 0805 physical size and likely something around 1uF. Anything larger than 1uF in a ~35V or higher rating is probably going to be in a larger physical size package than what's there. However, I've debugged quite a few circuits in the past and very very rarely have I ever seen a failed ceramic cap...maybe once out of a hundred or more circuit cards?

I think the biggest problem here is that the ESC was modified by the user and there is a snowball's chance in hell of S&T covering it under warranty. Taking a stab at what's wrong with the ESC by looking at some residue on the casing isn't going to do that. My suggestion is to at least send it to Mike or someone else with experience repairing ESC's or troubleshooting electronics to at least have a chance it might work again. I don't mean to sound harsh about it, but online troubleshooting of this ESC by pictures ain't gonna work. Case in point, we had a video deserializer card at work this past summer that someone killed when the voltage knob on the PS got bumped and overvoltaged the card. The only component physically damaged was a little voltage regulator, which we replaced. However, even after replacing that regulator, there was still a short circuit on the 3.3V bus on the CCA and absolutely no other physically damaged components on the board. The main point is, a component doesn't always have to be physically damaged in order to have an internal problem.