Problem with Childs 12v 4x4 car - from an Electronics dummy!

Does it look like this?>

Series

--Winston

h e e

t&add2=3D77Series

Yes, except it doesn't have the threaded bit at the top, mine is black and completely flat on the top.

Yes -- something's broke. Isn't that helpful?

You say you can follow the current right through to the motors -- what do you mean? When the accelerator pedal is depressed (I assume it's just a switch), there should be 12V across the battery terminals, and nearly 12V across the motor terminals. This means that the circuit path from the battery '+' terminal to the motor '+' terminal should have very little voltage drop, as should the path from '-' to '-'.

So, one way to chase this down is to hold down the accelerator, and trace down the point where you have a 12V drop in the circuit, instead of in the motor. When you find it, you've identified the bad spot.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

(...)

this?>

What Tim says.

Place your negative meter lead on the negative battery terminal. With the 'accelerator' depressed, place your positive voltmeter lead on one terminal of the Joemex breaker and note the reading. Then place your positive voltmeter lead on the other terminal of the Joemex breaker and note that reading. Both readings should be about the same, 12 V or more.

--Winston

Do you have some way to check the switches (DMM perhaps). Several years ago I pulled a few of these from the trash and found that the rocker switches were shot. I replaced 'em with some toggle switches, and away the boy went.

George H.

--
Lift the wheels which are providing traction, switch it on, and place
a jumper across the accelerator terminals.

If the wheels spin you have a bad switch.

(...)

What did you find out, Dazz?

--Winston

Your public wants to know.

--
www.wescottdesign.com

:)

--Winston

I haven't had a chance! I will post back when I have! Probably be the weekend! Thank you all for your time and helpfulness!

(...)

Winston > What Tim says.

Winston > Place your negative meter lead on the negative battery terminal. Winston > With the 'accelerator' depressed, place your positive voltmeter Winston > lead on one terminal of the Joemex breaker and note the reading. Winston > Then place your positive voltmeter lead on the other terminal Winston > of the Joemex breaker and note that reading. Both readings Winston > should be about the same, 12 V or more.

Also try that same technique with your 'accelerator' switch.

You'll narrow it down to the problem, I am sure. :)

--Winston

Technically, you don't "follow the current" unless you have a current probe. But your voltmeter should be enough. If, when you wire the motors directly from the battery, they work fine, then it's either the "accelerator" switch or that thermal fuse thingy.

Have Run! Rich

h e e

Now I'm even more confused than when I started!

I have managed to "follow the current" right up to the motors without them working! I'll try and explain the wiring. AS well as the accelarator switch there are also 2 switches which form the "gears" forward and reverse. If they are both swu=3Ditched one way the wheels are druiven forward, if they are both switched the other weay the wheels are driven in reverse. One of the switches contains the thermal cutout. I'm going to bypass these and see if it works. Will report back shortly!

tch

ave

the

is

s

Still not working, think I need to buy some new switches and rewire the whole thing!

(...)

Without a schematic it is difficult to offer much of value. It sounds like the battery is flat and needs a recharge.

Switching direct current is a much larger problem than switching alternating current because once an arc starts in an improperly specified switch, it can continue until the switch breaks.

Advise you locate a voltmeter (DMM) and take some readings as we outlined earlier.

Good luck!

--Winston

[...]

Welcome to USENET.

This ride-on sounds like the Mattel PowerWheels jeep sitting in my basement waiting for me to get back to it: two 6V batteries, a Forward/Reverse switch, a High/Low speed switch, and an "Accelerator" pedal.

The drive motors )and gearboxes) are mounted on/around the rear axle. Forward/Reverse is a DPDT switch that reverses the power going to the rear wheels. Low/High connectd the batteries in series (giving 12V) or parallel (sending 6V to the motors: slower speed, but longer operating time). The Accelerator is a simple on/off foot switch.

I was going to try to type in an ASCII schematic for you, but then I ran across this one in a forum post:

Read This First (FAQ's): The Definitive "Wiring diagram" thread

I don't recall your mentioning the specific manufacturer or model for your ride-on, but this site seems to cover a number of different types (FAQs on R/C and on those "push nuts" that are so annoying):

Modified Power Wheels.com Power Wheels & Peg Perego upgrades, Modifications, how to fix

You might also find useful information from these sites:

Power Wheels Troubleshooting Guide

Power Wheels Modification CD for Windows

Hope something in there helps.

Frank McKenney

--
  "When a true genius appears in the world, you may know him by this
   sign, that the dunces are all in confederacy against him."
                             -- Jonathan Swift

witch

have

e

m the

t is

me

ors

s

ll

Yeah the one I had.. (A power-wheel thing from Fisher-Price) also had a third switch that would do a low and high speed... Connected the two

6V batteries in series or parallel across the motor. And I think the reverse always ran in 'low' speed. So it took me a bit with pencil and paper to trace the circuits. The switches weren't completely shot so it would run sometimes. I was able to get it running for a while by just swapping switches. But eventually the 'long term' solution was to replace them. I mounted big toggle switches (from my junk bin) on the 'dash board'.

George H.

Finally got it working by replacing 2 switches and removing the accelerator switch! Unfortunately this makes it unsafe for my 3 year old as he waits till he has crashed before switching off :o) I cannot find a UK supplier of the accelerator switch, anyone recommend somewhere? I have tried Maplins already.

Is it a rocker switch? Digikey has a nice search feature. You can find a switch there and then see if Farnell carries the same brand.

itch

George H.