Reellgi 0 Posted March 28, 2020 Hi, anyone got this model, or similar like Porsche 930 or 924 from '80s? I need some photos of pcb or info about electronic boards. Many thanks https://www.tamiyaclub.com/showroom_model.asp?cid=128046&id=15762 Share this post Link to post Share on other sites
korreka 43 Posted March 30, 2020 Those 80´s toy grade cars have 6 functions control (7 functions including Stop). Here is a Nikko car with those functions: http://reparar-cochesrc.blogspot.com/2015/12/emisora-nikko-de-6-funciones-y.html Nikko used a square signal (50% duty cycle) for "forward - 350Hz" and "backward - 900Hz". On the "right" side it was 75% duty cycle and on the "left" it was 25% duty cycle. Taiyo used the same signal and frequencies but forward and backward were swapped. Other manufacturers used other I.C's decoders but the control signal was the same (the square signal frequencies could be different). Some of these i.c.´s are: TA7657 T8140 Share this post Link to post Share on other sites
Reellgi 0 Posted April 3, 2020 ok, thanks for explanation! Share this post Link to post Share on other sites
Reellgi 0 Posted April 4, 2020 finally found a photo. But if the model is full function type, why is there a potentiometer on the steering? Usually, at least in the small models, the neutral position is obtained with a spring and no signal in the steering motor. It looks like a servo. Share this post Link to post Share on other sites
korreka 43 Posted April 4, 2020 It´s a semi-proportional control car. The steering is proportional control and a single speed to go forward or backward. SN76604 i.c. was widely used the for steering control. Share this post Link to post Share on other sites
Reellgi 0 Posted April 7, 2020 you were right! two sn76604 and one 14069, so is full proportional? What was the hex inverter used for? Share this post Link to post Share on other sites
korreka 43 Posted April 8, 2020 It may be a flip-flop or monostable multivibrator built with inverter gates to separate the PPM signal into two PWM signals: Share this post Link to post Share on other sites
Reellgi 0 Posted April 9, 2020 there is a 1Mohm resistor near the 14069...maybe is one stage used as amplifier? Share this post Link to post Share on other sites