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Discussion Starter · #1 ·
Hi,

Rick, maybe you understand and can explain.

I chipped a brand new SCX Suzuki Swift JWRC, I think it is with the standard 41b motor. It had less than 2 hours running time at the time of the incident. The car was used approximately 1 hour over a couple of weeks before race-night. We were running a race where this car was used in every heat, each heat about 3 min driving, 2 min in between heats.

Anyway, halfway through the night the car refused to run, and there was a distinct "burn" smell coming from the car. When I opened the car it appeared that the component marked red below seem to be burned, and the chip becomes very hot when power is applied. Not possible to communicate with chip through software. Car was running flawlessly before incident, flawlessly afterwards when run "analog". Nothing really happened, it just suddenly did not start. Were running the track at 13.2 volts. The wires next to the "circled" component has some discoloration probably due to heat.

The chip was connected to the motor can as instructed.

What can cause something like this???



T
 

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Gidday,
Sometimes no one knows but there is generally a reason. Sometimes I find chips covered in rubber dust, sometimes I find peoples chips near the magnet. Sometimes its not near the magnet but during a crash the decoder moves to hit an axle or a magnet. It could be as fine as a loose braid wire fine as hair shorting out the board. It could be a short in the motor, the motor could have picked up something then spat it out.

Rick
 

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Discussion Starter · #3 ·
How can the chip be protected, will a diode between the chip an motor protect against any shorts or other issues on the motor side? (ref other discussions regarding worn motors and the like)

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QUOTE (injectorman @ 8 Jan 2012, 10:32) <{POST_SNAPBACK}>If it is a faulty chip or chips then that would explain it. Best to send the entire car to me to get to the bottom of it.
We tried but could not perfect it. Ive had this happen with a few brands including Scorpius but it's a rare event.
 

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After my testing is finished and I'm able to get consistent results from all cars, I plan on wrapping all the chips in electrical tape to protect them in case they come loose in a crash.
 

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Discussion Starter · #6 ·
QUOTE (injectorman @ 8 Jan 2012, 00:53) <{POST_SNAPBACK}>Gidday,
Sometimes no one knows but there is generally a reason. Sometimes I find chips covered in rubber dust, sometimes I find peoples chips near the magnet. Sometimes its not near the magnet but during a crash the decoder moves to hit an axle or a magnet. It could be as fine as a loose braid wire fine as hair shorting out the board. It could be a short in the motor, the motor could have picked up something then spat it out.

Rick

Hi,
Is it your experience that it is the shorts/debris/damage to the chip itself that causes chip failures, or is it shorts/debris in the motor that will cause the chip to fail?

Assuming some problems exist on the "chip" side of things:
I happen to know a little about tools used for logging oil/gass wells during drilling. These tools are so packed with electronics it's almost unbelievable. They are suspect to enormous forces (shocks, vibration), sometimes at very high temperatures, several thousand meters deep in the general direction of Hades. And they survive (at least very often;-). Various techniques are used, and cementing the electronic boards in epoxy is a very common method(fully covered, both sides). In addition electronics boards are usually fixed to rubber/foam or other flexible material that will absorb some of the forces.

As I can't see many of us fiddling with the car chips at a component level, maybe covering the chip in epoxy could be something to think about for future production runs? Maybe as a DIY recommended practice? Will definitely protect from dust, debris and mechanical impact.

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Why not experiment yourself? I was thinking of rubber latex dipping. However I like access to the chip too to resolder broken wires etc which is impossible if dipped. I tried to buy latex from a hobby shop, "Oh whats latex? " .... I gave up, maybe another time.

Rick
 

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Discussion Starter · #8 ·
Oh, will do:)
Just thought I would wait until the next chip version, where the issues currently under discussion in another thread is solved once and for all:)

Latex might be a very good idea. I was reading earlier tonight about making tyres, and checked out a few web-shops for urethane and silicone rubber. Think I saw a couple of those shops selling latex as well, Polytek being one. Unfortunately, none of them would ship their stuff up here to the outskirts of civilization.

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Chip issue was a simple one now fixed.
 
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