Hi guys.
Recently got a faulty RC toy from ebay.. nice toy indeed - clean and neat, no visible usage and the fault was stated as "moves only backwards". Alright, faulty switch was my first thought... yes, but no.
Indeed when the car and the remote are powered, they automatically pair ( takes less than a second ) and after the first input, the car starts moving backwards until powering off the remote or the car. During that time, the other channel ( steering ) works fine.
Since the car is 4x4 and with two steering axles ( no differentials tho
), it has 4 different steering modes selectable from the remote control ( front/back axle only, crab movement, both axles steering in the same direction ). The selection is done by pressing one of a 4 buttons while there is input on one of the 2 channels ( so during movement or steering ). That mode selection worked.
So, in the remote control there is a main pcb with few auxiliary ones for buttons, switch, led, etc.
On the main board there are 4 switches, one voltage regulator, some passives and... a 16 pin mystery IC.. and... 2402 memory IC.
In the car there are two "drive" ICs ( most likely transistors.. I just did not bother to even read their labels ), few passives and... another mystery IC which looked exactly the same as the one in the remote ( even the pinout was similar - power supply, gnd, antenna.. ).
After some troubleshooting I just found out that each component on the remote board reads exactly as it should and all traces are fine..
In the past I've had bad experience with the 240x atmel memory ICs, so just decided to remove it and try without it... and voila.. the car runs forward, backward, sideways, etc... it just does everything that is supposed to do.
So does anyone have any idea why this memory is there? Also could anyone provide any info on the mystery IC? I'm really curious to find out more about it...
On the top of the IC there are no markings. On the bottom tho, there is some text printed + probably some manufacturing info ( see photos )
sw1 and sw2 are the fr/back movement and the steering
Recently got a faulty RC toy from ebay.. nice toy indeed - clean and neat, no visible usage and the fault was stated as "moves only backwards". Alright, faulty switch was my first thought... yes, but no.
Indeed when the car and the remote are powered, they automatically pair ( takes less than a second ) and after the first input, the car starts moving backwards until powering off the remote or the car. During that time, the other channel ( steering ) works fine.
Since the car is 4x4 and with two steering axles ( no differentials tho
), it has 4 different steering modes selectable from the remote control ( front/back axle only, crab movement, both axles steering in the same direction ). The selection is done by pressing one of a 4 buttons while there is input on one of the 2 channels ( so during movement or steering ). That mode selection worked.So, in the remote control there is a main pcb with few auxiliary ones for buttons, switch, led, etc.
On the main board there are 4 switches, one voltage regulator, some passives and... a 16 pin mystery IC.. and... 2402 memory IC.
In the car there are two "drive" ICs ( most likely transistors.. I just did not bother to even read their labels ), few passives and... another mystery IC which looked exactly the same as the one in the remote ( even the pinout was similar - power supply, gnd, antenna.. ).
After some troubleshooting I just found out that each component on the remote board reads exactly as it should and all traces are fine..
In the past I've had bad experience with the 240x atmel memory ICs, so just decided to remove it and try without it... and voila.. the car runs forward, backward, sideways, etc... it just does everything that is supposed to do.
So does anyone have any idea why this memory is there? Also could anyone provide any info on the mystery IC? I'm really curious to find out more about it...
On the top of the IC there are no markings. On the bottom tho, there is some text printed + probably some manufacturing info ( see photos )
sw1 and sw2 are the fr/back movement and the steering
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