Conference vmszoo::rc

    If the car has been crashed, you may have a cracked Rx Xtal.  I
    had a BMW 3.0CSI a few years back that exhibited the same
    symptoms.  Ran fine mostly, but every once and awhile, for no
    reason, it would just seem to lose control.  I replaced the Xtal,
    and it worked fine.

    Try putting a capacitor across the leads into the motor.  With new
    brushes you will usually get enough sparks generated to cause
    significant RFI.  Any hobby shop that sells electric cars should
    have them on hand.  All the racing electric drivers have capacitors
    across the leads into their motors.  Good Luck!

    I agree with .2
    
    I put 47uf capacitors across the positive and negative leads on
    the motor and it clears up this type of problem...
    
                                            Tom 

    
    How would this explain the fact that it takes off on its own (with
    the motor not running, there should be no noise, hence it shouldn't
    take off on its own, right??)
    
    It sounds like your receiver antenna is broken at the receiver.
    This would give the symptom you mentioned where moving the transmitter 
    antenna affects things.
    
    Bill
    

    
    The JRL car is brand new - bought on 12/10/88 and so are the batteries,
    so I hope it has no defects.  I have tried the car in Hudson and
    in Acton (both times indoors) and saw the same type problems.  Should
    I try it outside, and if so, where is a good place to do that ?
    
    A friend who has RC car experience said that the car is a poor design:
    it should have a separate supply for the receiver and one for the
    motor.  Could I add a small supply (separate, but with common ground)
    to drive the receiver ?  Also, would a larger antenna on either
    the trans. or rec. be a good idea ?
    
    	Tired of a spastic car,
    			Chris
    
    

>    The JRL car is brand new - bought on 12/10/88 and so are the batteries,
>    so I hope it has no defects.  I have tried the car in Hudson and
>    in Acton (both times indoors) and saw the same type problems.  Should
>    I try it outside, and if so, where is a good place to do that ?

In your driveway.
    
>    A friend who has RC car experience said that the car is a poor design:
>    it should have a separate supply for the receiver and one for the

Some of the best and fastest cars going don't have separate batteries.    

>    motor.  Could I add a small supply (separate, but with common ground)
>    to drive the receiver ?  Also, would a larger antenna on either
>    the trans. or rec. be a good idea ?

No - the transmitter and receiver antennas are designed to me a multiple
(or even fraction of the wavelength of the frequency.  The length is
moderately critical.  If in doubt take the system back to the dealer
and demo the problem to him.

I agree it sounds like capacitors on the motor and I also agree that
if it takes off by itself that it must be the radio system.  

If it takes off by itself you can disconnect the motor and play with
it on your kitchen table until you somehow stop the servos from
glitching.  (try wiggling wires).

Bye          --+--
Kay R. Fisher  |
---------------O---------------
================================================================================
    

    >"...and charged the battery pack for 6 hours (its first charge)"<
    
    If this is a standard 7.2v 1200 mah battery pack, and you "trickle"
    charged the battery, it simply isn't fully charged.  7.2 packs must
    be charged 12-18 hours depending upon the "trickle" charger.  The
    best "first charge" is with a trickle charger (which also should
    be used from time to time to erase any battery "memory").
    
    Try a 12 hour trickle charge, or a 15/20 min quick charge to see
    what the car does...
    
    

    My eight year old son received a JRL '57 Chevy for Xmas and the unit
    had been running with no problems. He took it out to play with last
    weekend and immediately informed me that it wasn't working. With the
    Xmitter and car switched on the drive wheels are turning in reverse
    with no ability to trim to neutral, engage forward running or control
    steering. Switches on wheels turning in reverse I placed it on the
    basement floor and the car barely moves. I have replaced the 9V battery
    and both slow and fast charged the 7.2 battery pack. I have also
    checked for loose or broken antenna connections and the visible
    condition of components for breakage. I don't believe that the car has
    been dropped or battered. Does anyone have any additional ideas short
    of returning to the manufacturer?

    It sounds like a battery problem.

    I'll assume the 9V battery was in the Transmitter.  I'll assume the car
    Receiver uses the motor battery for power (if not, you haven't replaced
    all the batteries).  This being the case, it sounds like the car's motor
    battery isn't getting charged.  Perhaps the charger itself is not
    working.

    Randy
    

    Make that two votes for "no juice".  Check the connectors on battery
    (the 7.2V pack, which I'm assuming the car uses), car, and charger.
    Check the fuse in the charger, or somehow verify it's putting out.
    Look for a seperate receiver battery/batteries in the car.
    
    Good luck,
    
    Greg