Help, Z-Car slows to a Craaaawwwl

[MST3KPIMP]

Has this happened to anyone? I'm drivin my z-car and everythings fine and then suddenly the car slows to a crawl.. I charge the battery and still slow as mollasess just barely moving. I tried different motors, new battery same deal.. Wheels tun freely with no lint or obstructions. Did I fry the PCB somehow? I'm thinkin some wire is touching something it shouldnt or some transistor is blown but i dunno.. any thoughts?:(

[FMZPLAYER1]

I have blown motors from doing jumps with a Z-car, but it's been fine with other motors, It likes tomy 2.2's but 2.6's can load the board down a little. (just has slow starts but still runs)

It's pretty hard to blow a transistor (if you are still running single cell) -Is reverse just as bad?, could be the battery/battery connectors in the car, or weak transmitter batts.

Try running your car while it's charging, check for same speed fwd/rev (sometimes reverse is faster, but usually not by much)

If the car batt is going bad, it will run real fast while charging, but slow down when the charging stops, If the batt is good, the speed should be only a little slower when the charge time is up.
If the car batt is weak, the steering will really slow it down too.

Maybe try charging with another controller (if changing the controller batts didn't work).

I have had lint pack up behind the idler gear (only found it after gear swapping with a clone)--axle looked clean, motor too..

[MST3KPIMP]

no its not lint this time.. Heres what I think might be the culprit. I've been running it wit the pcb cover off & the red wire that connects to the led snapped off and I see that if I touch the heatsink or one of the various transistor thingies while its running it will stop or stutter. I suspect the broken wire was making contact with one of these bits and fried something or other and it now runs at a snails pace. I'm looking for some signs of a burnout but it seems like internal damage. Is there a specific transistor that allows a faster speed?

[FMZPLAYER1]

Could try a pcb swap with another clone, actually, some of those "thor" clones will work with a Z-car controller (the ones that dont have the motor hardwired).

You might have one partially blown transistor there, if you have good reverse, and bad forward, that can be a clue, -(assuming froward was when that wire came off and touched something it shouldnt)

The transistors could be swapped out, but they're kinda tricky to get off, without messing up the board.

If you still have reverse, you could switch the motor leads around so reverse is now forward, and reverse is just "brakes"

There is a way to use a digital meter to test transistors, basically checking them like they were 2 diodes in one case. One lead is common or "base" and is positive or negative (the other leads are the opposite) Two kinds of transistor "P-N-P" and N-P-N", on a PNP, the base is negative, and on a NPN, it's positive.

You know you have found the base lead when you get .5 to .7v drop across the terminals, if you have it probed the right way.
When transistors go bad, they either short out or go open, so thet meter would give a real low reading (diode test setting used) like 0.1v or less. If it's open, it will be like there's no transistor anymore.

[Fastandfurious]

i think these could help

-check the + and - terminals going from the batt to the PCB
-check the + and - terminals going from the PCB to the motor
-try charging it two times
-replace the motor
-replace the battery
-make sure the battery contacts are clean
-make sure the motor contacts are clean

-IN THE WORST INSTANCE YOU MIGHT HAVE TO RE-SOLDER SOME WIRES OR REPLACE THE PCB!!!!

if none of those work go buy another car

[MST3KPIMP]

ya i figured out that it was just a crappy motor.. i replaced it witha kit racer motor and it works nice.