havin some really bad problems latley...

[pvtdonut]

hey all, im new to the forum. so let me start by saying hello.

hello.

ok..now that thats out of the way...

i have recently gotten back into xmods, theyre fun, not too costly, and can go pretty fast if you know your stuff...unfortunatley, im having too many problems with mine though lately.

heres what happened:

i have recently bought a transformers kit to upgrade after doin some browsing, seeing that there are people that can make them go fast. its the evo chassis. soooo..i got a stiletto chassis off ebay, installed that, along with the li-ion batteries, and awd kit. i ran the car a few times so far, worked great. until now.

i have purchased the aluminum rear drive line case. i installed it, but now it seems like every time i go to run it, it fries my fet. its happend to three cars so far. im lucky that theyre only about 17$ each.

what is going on here? why is this happening to me?
please give me some advice on how to fix it... its a stock motor, i never upgraded that at all. what am i doing wrong with the aluminum piece thats making it fry? it worked fine with the regular plastic part, but now its not. if you dont know what part im talking about, its the part that the motor and the gears are inside of, on the rear of the car.

please help! im tired of having to buy a new car every other day...

[TheB1GDude]

It sounds like your board is bridging on something (possible the new drive case, although I would have thought they would be far apart from each other not to), which is causing a short and burning out your board, when you fit the drive case juat make sure there are no loose pieces of metal floating around and that the bottom of your board isn't touching anything other than plastic.

[pvtdonut]

well, the fets are what keeps going out on me.... i see a small spark and then smoke coming from the rear fet. and since i have the tiletto chassis, the board is resting on top of the batteries, nothing under it to touch it...

like i said, it worked fine with the plastic part... i just started having this problem with the alumiinum casing... could it be due to the meshing of my gears in the case?? theyre the stock ones right now...they do turn, but sometimes slip...i dont think that would be the problem....the slipped even more in the green stock housing....

[TheB1GDude]

Ok so it sounds like you have more than one problem, it might be an idea to put some photos up so we can help further.

What I will say is I can't see your fets frying because of gearing, its far more likely to be something bridging.

As for your gears slipping well did you buy the chassis from a legit seller or is it from an overseas seller, if you bought it from say someone in china or Japan then its probably a knock off and I know a lot of people have had issues with the chassis being poor quality, which might explain the gears slipping.

[pvtdonut]

the chassis and batteries are from atomicmods.com, i got it on ebay, but the seller gets all of his parts from there cause its the same description and products.. and the casing was from hobbysmart.com, but the manufacturer was GPM.

what exactly should i take pics of to show you? ill take pics of like...where i soldered the engine wires to the board, and the battery wires to the bored as well... and maybe a pic of the car without the motor in there....

[2wdpancar]

Okay, here's your problem:
You could've soldered the wires in the wrong spot, so the polarity is different.
These ebay peeps DON'T buy from atomicmods, here's where they fool you.

They are cheap POS's, and they have crappy hardware, the Lithium cells are very old, the wires are RS quality(crap), and they use fake dean micro connectors.

There is no circle around the atomic symbol on the ebay stilletto, but on the real one there is, why? Because ebay sellers sell fake knock-offs.
Sorry to come onto you so harsh, but that's the reality, and how it is.

It could be wrong polarity, a serious case of binding, or some other mystery of the Xmods...

Get us pics of the soldered harness spots, and do solder your wires directly to the board?
NEVER run a motor on the stilletto without insulating the metal tabs on s1/s2 motors, as they can easily become loose and touch, hence frying FETs.
cut the heatshrink off the motor tab, unsolder the wire, and solder it to the corresponding spots on the board(pads to which you screw the motor tabs in).

[suicide_star]

if it ONLY happened when you installed the rear gear case cover, it may be binding, i noticed on one of mine (and it is actual GPM) my rear differential fit very, very tightly inside of it and started to bind. another thing you may want to look out for is to make sure that your rear differential is not bowed, this would cause it to bind at certain parts of the revolution. it doesnt take much to burn up your FETS.

[pvtdonut]

i did the whole, cutting behind of the motor wires then soldering the wires to the board where you would screw them in... i did manage to bring one of the cars that i just fried back to radioshack and exchanged it for a new one....which is pretty cool....i put it back together so it seemed like it was untainted. quick soldered all the wires back to the stock chassis and then got it back together...im gonna do it with another one i fried... i soldered them the way they were taken off...red in back and black in front... so it might be something with the gears in the casing when i used the aluminum... im gonna just save up and get a new locked diff, and the derlin gears off atomic..

i made sure that the motor wires that i soldered to the board did not go over the brass spot and touch a fet.... i have the plastic gear case on there now and it works fine. no burning up or anything.

thanks for letting me know i wasted money on knock-off parts...lol but it IS lighter than the stock chassis and it does go pretty quick right now.... when i trade in the next car, ill use that one as a top of the line racer...right now, this one is good for a beater....

I would recommend stacking your fets or getting an external spider. What kind of motor are you running? The RS stg1 or stg2 should be fine with liths, however if there is the rear motor case binding the amp draw will increase putting more resistance on your FETs, this might be the case. An FET stack/spider/v2.2 will give you the ability to run motors with more draw, or help to prevent your current problem from ruining more FETS.

[2wdpancar]

Originally Posted by Surgeon

I would recommend stacking your fets or getting an external spider. What kind of motor are you running? The RS stg1 or stg2 should be fine with liths, however if there is the rear motor case binding the amp draw will increase putting more resistance on your FETs, this might be the case. An FET stack/spider/v2.2 will give you the ability to run motors with more draw, or help to prevent your current problem from ruining more FETS.

Even then, if the problem is binding, it could just fry the spider or whatever FETs he'd be using.