Wheel till it breaks...

frizzen · Post by **frizzen** » Sat Jun 24, 2006 1:19 am

Ok I managed to pop something important on a ZZ-M. I haven't even been abusing it, it's still under construction and I've only driven it like 4 times.

I just wanted to charge up the battery again and make sure my newly fabricated body circuitry was working. Charged truck ok, hit the TX...nothing.

If you hold the ZZ-M looking from top with front axle to left, on the left side top between C22 and Q13 there's a little black can looking thing. One side was lifted up, gently pushed it back down, still didn't even make an intermittant enough contact to work, set it back down on my desk and the rest of it's connection to board let go.

It appears to be some kind of ferrite core coil; but can't figure out what is it, and which circuit is it in? I'm guessing part of the RX?

Once we know what it is, any idea if it could be repaired? how well it swaps at component level? Or should I just swap in a new ZZ-M board?

betty.k · Post by **betty.k** » Sat Jun 24, 2006 3:42 am

i'm no real help, but it gives me an excuse to get another pic with the new toy

this bit?

crazydave · Post by **crazydave** » Sat Jun 24, 2006 8:08 am

Yeah, you know, I don't know what that is. I want to guess, the inductor for the RX, but i really have no clue.

At any rate, I'd reccomend you just set that board aside for now. If you can find a micro stunt car, like the big wheeled ones that had tank steering, or the ones with the spinning front ends, those PCBs have dual H-bridges so you can drive your steering motor as well. Hogjowls had used a similar board from a Muscle Machines RC.

I just reccomend that because I see those cars for like $6, but if you've already scored some of those $4 MTs, then I guess that would be more cost effective.

ph2t · Post by **ph2t** » Sat Jun 24, 2006 9:44 am

from it's position and proximity to the 3 legged black device I'd say it's an inductor that is part of the DC-DC convertor circuitry on the ZZMT pcb.

You know the ZZMT pcb actually converts it's DCDC drive to 5V. Off the 2.4V supplly all of that PCB (execpt the h-bridges that drive the motors) runs at 5V.

I would say it's around 22uH - 100uH, but that's only from experience with DCDC convertors.

If you can, just swap the PCB out....may be easier....

frizzen · Post by **frizzen** » Sat Jun 24, 2006 7:50 pm

Yep, that's the part.

I went ahead and did some distructive testing. It's a little ferrite core, wrapped with magnet wire, with a ferrite cover to enclose it all. Due to the construction, the inner leg of the magnet wire couldn't be lengthened without unwinding the whole coil, after I wound off about 3" the wire flaked off a chunk of glue and then broke. So anyway, definately was an inductor.

How do the stuntcar boards compare to zz-m? More power, less power?

I wanted to keep the board on this truck stock (the rest of it should be extreme enough) but that probably does sound easier

crazydave · Post by **crazydave** » Sat Jun 24, 2006 9:53 pm

frizzen wrote: How do the stuntcar boards compare to zz-m? More power, less power?

They should be right about the same, depends on the board I guess. You lose lights, but they are more compact and easier to FET mod.