korreka

On this site you can see an analysis of the Dictator's electronics: https://reparar-cochesrc.blogspot.com/2017/02/mantenimiento-reparacion-de-emisora.html

In previous posts, I explained how the "H brigde" of transistors works that drive the motor.

If the car motor does not turn when "forward" or "backward" is activated on the remote, there may be another fault. A single blown PNP transistor would cause either "forward" or "backward" to fail, but not both. You have to check if pins 9 and 10 have the correct signal. There are many PNP transistors that can be compatible and can be purchased on AliExpress, electronic component stores,...

In your picture, the black transistors are NPN and the green transistors are PNP. The format of the terminals are BCE (base collector emisor). I can´t know the technical specs of that . Nikko use 2SA1129 (PNP) and 2SC2654 (NPN) transistors in proportional RC cars with the same scale and motor. These transistors are 7A average current (15A peak current). Your can search other 7 amperes bipolar transistors with BCE format. One important thing: the "heatsink" of the transistors is connected to the central terminal (collector). If you put the cooler touching two opposite transistors, you will create a short circuit. Mica, silicone or plastic washers are used so that the screws and the cooler do not touch the heatsink. Pins 9 (forward) or 10 (backward) are activated (3 to 5 V ) when you press the throttle on the controller. Check with a multimeter to see if the L9367 chip is working.

In case it helps, it is a Chinese or Taiwanese RTR car and it was also sold like these brands in other countries or they have very similar parts: * Bandai Intercepter * Hoptron Condor * Joustra Racing Fox * Play Group Super Cougar * Plusdis The_Missile

This is my Traxxas TRX3 buggy: the front suspension bulkhead (part 2630) was broken. This part is quite difficult to obtain due to the age of the buggy and the fact that it frequently breaks in jumps or collisions - it is in high demand. In this picture you can see the wishbones, bulkhead, axles and other elements of the front suspension: There is another Traxxas black bulkhead part, ref. 2530, from the Bandit buggy that is wider. It has the holes marked in red in the same relative position and the part would have to be cut along the yellow lines to make it an alternative. Once it has been cut, it is screwed on since the 3 holes on each side match in relative position on the chassis, subframe and lower arm. This photo shows the alternative bulkhead compared to the original. We place the suspension tower and lower arms. With the chassis and subframe screws, the bulkhead is firmly attached, but the halves are joined in one piece with epoxy adhesive as seen in the picture: Finally, just 2 more holes need to be drilled in the bulkhead for the bumper: In the following pictures, the final appearance of the buggy with the vintage electronics: * Sanwa SRC-2322RS 40Mhz receiver * Sanwa SM-102 servo * LRP Ics 8066 75A electronic speed controller with XT60 connector * Kyosho Kspeed 15T motor. This TX3 rebuild can be translated into Spanish here: https://reparar-cochesrc.blogspot.com/2024/03/Traxxas-TRX3.html

".... find out how to set the oscilloscop working!)...." To view the PPM signal on the oscilloscope:: - Timebase --> 2mS/div - Input ---> DC -Input level ---> 0.1 or 0.5 V/div You can see the signal at pin 9 of the OKI L9362 i.c (transmitter ---> 0.1 V/div) or at pin 16 of OKI L9367 (car ---> 0.5 V/div)

kinxkinx "... 1 have arround 2V on pin 9. Korreka, do you think the L9367 can delever 2V continuous? Or is it a pulsed signal? That doesn't make sence to me as the motor has full voltage!...." Without the oscilloscope we do not know if the voltage is continuous or if there are PWM pulses (the throttle is not at 100% of the range). If 2V is able to activate the power transistors and there is 9.6V of voltage measured at the motor, everything seems fine. ".....I doesn't try the 3 other cars well, but on one of them, the motor is short-circuit. I have disconected it to test the board, but some things look weird : I have 5V on the 9 pin, and no voltage on the pcb to motor output. I try to test the power transistors. I guess that when there is voltage on the base, there must be a very low resistance between the collector and emitter ?..." If the motor is short circuited, surely one or more power transistors have burned out. You can put a 33ohm or 47ohm resistor instead of the motor or a small 12V bulb (old car dashboard indicator bulbs); To test an H-brigde transistor, a load is necessary. Between collector and emitter you do not have to measure resistance in ohms, but you must measure 0.6V if the transistor is active in saturation. Remember that two transistors are activated in "forward" and the other two in "backward" "....And I had also some problems with rim/tires frictions. Rims skate in the tires... I'm quite a newbie, I just change the wheels with another car, but must I glue them?..." In old tires it is common for the rims to skate in the tires. Use Contact Adhesive instead of cyanoacrylate to avoid damaging the rims. You can also insert a thin elastic band into the edges of the rims. Mouc-RC "...Hopefully Sir Koreka will get a Mk.1 & confirm the PCBs are just different.,.." If I get a mk1 transmitter later, I test it with the oscilloscope to see the pulse signal and its duration.

Hi, First of all, when measuring voltages you must have the motor running. So the battery current is high, you can see if there is a suspicious voltage drop in the wires, solders, switch, and even the battery itself that is weak. Remove the rear wheels or put the buggy with the wheels on the air to do this. * If you want to measure the maximum no-load speed of the motor (RPM), use an "audio spectrum analysis" App. I use Spectroid app. Measure the first pulse in Hz and multiply it by 60 seconds. The motor must be outside the gearbox. Video: https://www.youtube.com/watch?v=_Y93yM2kLog * An H-bridge is a circuit of 4 transistors (2 NPN type and 2 PNP type in the Tamiya QD) to allow the change of direction of rotation. In one direction of rotation, only one NPN and one PNP transistor are activated. Active transistors work in saturation mode: the voltage between emitter and collector is 0.5 - 0.6V. That is, if you have 12V power between emitters, in the motor at maximum speed there are: 12V - 0.6 - 0.6 = 10.8V. This test is done with the motor connected. * On pins 8 and 11 of the L9367 circuit there should be about 6V (circuit supply voltage). On the electronic board there is a voltage reducer (circuit with Zener diode) for this. * On pins 9 - forward (or 10 backward) of the L9367 circuit there should be about 4V at full throttle. It is a pulsed PWM signal visible with an oscilloscope. This signal activates and biases the H-bridge transistors. The signal information is in the duty cycle, not in the voltage. I recorded this video in a Nikko proportional control car: https://www.youtube.com/watch?v=muKW6eYPamE I believe that the 1st gen transmitter pulses are shorter or longer than the 2nd gen transmitter. Then, the buggy waits to receive the original pulses. Try turning the throttle neutral trimmer on the buggy board in case it corrects it. * With Ni-CD or Ni-MH batteries, you achieve better results in a Tamiya QD because they have a higher maximum current discharge than an AA alkaline battery. Alkaline batteries have a higher internal resistance and if the motor requires a lot of current during acceleration, the voltage drops a lot. The best Ni-MH AA batteries are Eneloop brand, widely used in powerful flashlights. They say that Ikea's Ni-mh AA batteries are "white label" Eneloop. Li-ion (3S) can also be used if they fit in the battery box. * I assume you belong to the "Tamiya Quick Drive" group on Facebook. You can ask there if anyone has used a first generation buggy with a second generation transmitter. * A low-cost oscilloscope (20Khz) can be made with an old laptop through the sound card. Don't do it with a new laptop in case you damage the sound card. With 20Khz of bandwidth it is enough to see the signals of the PWM speed control pulses and the PPM of the transmitter. It is easier to configure the sound card with W98 or XP. The test leads are self-made with resistors to achieve an attenuation of 1:10 or 1:20 because the line input of the sound card supports 1 Vpp. This oscilloscope only allows you to see pulses or alternating signals; DC voltages cannot be seen. See this: https://reparar-cochesrc.blogspot.com/2016/01/osciloscopio-traves-de-tarjeta-de-sonido.html

kYOSHO ICARUS (sold by Graupner) https://reparar-cochesrc.blogspot.com/2020/03/restauracion-reparacion-de-kyosho-icarus.html

I don't have any first generation buggies. The second generation transmitter uses a potentiometer on the throttle trigger and sends the standard PPM signal and each pulse varies between 1 and 2 msec; a hobby transmitter of 27Mhz (80-90`s years) uses the same signal. It is possible that the first generation transmitter uses a switch on the throttle trigger and fixed resistors and the pulse is not in the 1-2 msec range. An old motor with worn brushes is slow and has no power. The motor 280 of the second generation buggy has 17000 rpm (no load) at 7.2V; It may be the RC-280SA-2865 motor. There are similar motors with these specifications on Aliexpress or eBay. Also check and clean the battery terminals; Sulfate and oxide do not allow the current to drive well.

Hi, Before replacing motor transistors, you should check many things; You should have a multimeter at least (if you have an oscilloscope, the better). * Clean rust and sulfate on the battery terminals, cables, soldering points, etc. with oil or vinegar. * check the antenna and the soldering point (cuts or cracks on the board) * Check the continuity of the battery and switch cables with the multimeter; The sulfate corrodes the copper inside the insulator. * You can test the car with the original transmitter or with a 27 Mhz hobby transmitter and appropriate frequency band (steering and throttle are swapped) * Check the quartz crystal socket and plate (cuts or fractures) and crystal pins for movement; change the quartz crystals for others to see if it works. * Turn on the transmitter and the car and check the voltages on the switch (12/9.6V, orange and blue wires), pins 8 and 11 (6V), pin 12 (2.3V). * On pin 16 you can signal the transmitter if the receiving stage works well. * there are two trimmers (throttle and steering neutrals); Turn the trimmers a little because sometimes it gets dusty; If you have electronics cleaner, use it. * on pins 9 and 10, the forward and backward signals are output to the transistors; They can be seen on the oscilloscope (https://www.youtube.com/watch?v=muKW6eYPamE). With the multimeter and the throttle lever at 100%, the voltage would be about 4V. * Check the motor connected directly to a battery.

My Super Saber car has a transmitter with LED. The car is fully proportional throttle; The electronics have OKI L9362 and L9367 circuits with 2 fully proportional channels; Believe me, I'm an electronic technician. I have seen other 80's RC cars with L9367 circuit and 2-speeds throttle but on the circuit board, they had relays and a power resistor to drive 540 motors. In the 80s, a relay was cheaper than a power Mosfet transistor. It is possible that the "early" QD cars were sold only in the USA and UK and the "second generation" was sold worldwide.

Proportional toy-grade RC car manufactured in Spain in 1976: Bianchi Ray-1 Entry to my blog site : https://reparar-cochesrc.blogspot.com/2017/01/emisora-y-coche-bianchi-ray-1.html

Tamiya QD Super Sabre "technical review" The Tamiya QD series (1/14 scale) are advanced toy grade cars that were many people's entry into the world of RC cars. The transmitter electronics have the OKI L9362 encoder integrated circuit and the encoded output is on pin 9. There are two internal potentiometers for steering and propulsion adjustment. The transmitter has channel 1 as throttle and channel 2 as steering (in reverse of a hobby-grade transmitter). PPM signal on pin 9 of the OKI L9362 i.c. The circuit diagram of the transmitter: This buggy was powered by 8 AA batteries. I have removed the battery terminals to insert a 9.6V NiCd (Ni-MH) battery. To disassemble, you remove the body (3 screws) and an electronics cover (4 screws) on the car. The car circuit board The power supply connector is soldered as seen in the picture. There are two holes to adjust the neutral of the steering and throttle on the circuit board. The electronic board has the OKI L9367 integrated circuit; pin 16 is the input signal coming from the receiver and on this pin you can see the amplified PPM signal. This one is the diagram: The 27Mhz receiver, demodulator and intermediate frequency filters is very similar to the diagram shown in the OKI L9362 datasheets: And the signals are these: The rear wheels have a 6mm hex axle; the hexagon can be pulled out: it is inserted into the splined shaft. The shaft is 4mm diameter and the nut is M3. To remove the gearbox, first remove the shock absorbers from the brackets. Remove the motor cover and then remove the motor. The gearbox is held by 4 screws on its bracket. The 280 motor has an 8 tooth 0.6M pinion. Its specification is 17000 rpm (not load) at 7.2V (0.32A) or 22,600 rpm at 9.6V; It matches the RC-280SA-2865 motor specifications. To access the inside of the gearbox, 3 screws are removed: The gearbox has two speeds: slow speed: 1: 16.3 ratio (40/8 * 49/15). fast speed: 1: 10.2 ratio (40/8 * 43/21).. The speed with the 67mm diameter wheels would be around 21 or 22 Km/h. This car has front independent suspension with friction dampers (spring only) without any additional anti-rebound system. The rigid rear suspension was inherited from another Tamiya buggies (Hornet, Grasshopper). Spare tires are hard to find; If we want to change the rear wheel for a standard 12 mm hexagon wheel, we can do it with a 4mm hexagonal adapter (with grub screws): Wheel axle detail. The Super Sabre in action (Badiola RC photographer): These thread is in spanish lang. in https://reparar-cochesrc.blogspot.com/2015/12/reparar-antena-de-emisora-tamiya-qd.html