I've found a ZZ SE design fault.
 

Hi everyone,
Those of you that have several ZZ SEs might have noticed that some are faster than others, or some ZZ SEs dont have the 'punch' off the line when you go to accelerate.
I have been working on many of these cars and was puzzled as to why it was some are weak even after being fet modded, actually the difference was more pronounced after fet modding.
Believe it or not, in some cars the digital control is backwards, yes, BACKWARDS. Not the motor polarity control, but the digital speed control steps.
The car goes forwards when you command it to go forwards, but it is only on 3 steps of forward control instead of the 5 that it is supposed to be.
The way these cars are setup is that they have 5 steps in forward control and 3 in reverse, making reverse slower and weaker. Thats the way it is supposed to be.
Some cars (very few) have their drive control signalling installed backwards.
The telltail sign, is that it runs faster in reverse than it does in forward, because it has the 5 steps incorrectly set to reverse.
And this is especially obvious once the car is fet modded.
Its easy enough to test, just hold your car up to your ear and run it, if it sounds faster in reverse then you have got a car with the problem.

The way to fix it would be to reverse the wires to the motor on the pcb (and dont forget to change the filter capacitor polarity as well) and then switch over the L / R switch on the top of the controller and it should work again.
It will always be a bit different in that if you want to use that controller on other cars as well, you will have to switch over the L/R
Just thought I'd post this and get your opinions, and let you know.
uA

I think my old savanna did that, vut it's dead now. Nice find though

Great find man.... you come up with some better stuff than the people selling em..

Thanks for the fix too.



silla

Thanks Payaso, I appreciate the comment.
:) uA

LOL!!! I have one that was doing that and I thought it was something I did, so I put it aside because I didnt' have the time to verify the problem..

Man, does it never end with these things? ;)

Ah well, thats good to know, and not too difficult to fix.

You saved me about 2 hours on the scope!

Thx!

Rob

No problem cbz, happy to help.
:) uA

Then surely you'd be happy to help us by sharing your method on how to do your SE mosfet mod? :rolleyes:

Chuckster...

Howabout you get off yer ass and figure it out yerself, micro_amps is a pioneer in all aspects of micro RC, and I would rather pay cash for his work than steal it and put him out of business!!!!