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What just happened?
#1

    I recently purchased two C7005 in car chips. I have never used this chip before, preferring the larger Slotit chip, but the cars I'm working on now are smaller and don't have the room. 
 The first one went into a Scalextric C3 L88 vette. Install went well and car functions were perfect. 
 The next chip I stuck into a Scalextric Ferrari 330. Again the install went well and testing showed it worked flawlessly. That is until I put the top half of the body on. Then the car was dead. No lights, no movement, nothing. 
 Now when I test the chip, no electricity seems to pass from the guide leads through the chip and the only way to make the car run is if I connect power to the chip where the motor wires connect to the chip. 
 Is the chip shot? What could have happened? The bottom of the chip was resting against the the motor case when I put the car back together. Could this have shorted something on the chip? 
 I see Dr. C has a thread about replacing mofets and diodes. Is this a solution to revive the chip? 
 I've attached some photos for reference.
   
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#2

You probably clamped the chip and shorted it out .

But "Never" power a chip like you have done by powering at the motor outputs, if it wasn't bjorked it will definitely will be now...

If you have good soldering skills it's an easy and cheap repair .
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#3

First diagnostic steps are easy.

1/ Disconnect the wires to the motor and insulate both using PVC tape or similar.
2/ Place the car on an SSD powered track with a lane changer and set its flipper to the ‘lane-change’ position.
3/ Manually roll the car across the sensor of the lane changer. Does the flipper switch back to the ‘stay straight’ position?

If yes then the microcontroller is running normally which would be good news.

If so the next step would be to remove the two MOSFETs (motor and brake) labelled NO2 and PO3.

Then first only refit a new NO2 and test for correct function of the motor (but no brakes).

All being well then refit a new PO3 and this should bring the brakes back too.

As a side note, it is critical with the C7005 to ensure none of the circuits on the decoder come into contact with anything conductive e.g. the motor casing. Insulating tape is your friend.

Good luck!

c

(BTW from the photos PO3 looks damaged - but likely NO2 is damaged too).
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#4

Dr_C
Thank you for your input. I will perform the test you describe. 

Could you please provide a  source where the two   components that I may need could be purchased?

Scott
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