This last year I decided on a change from audio projects and got into some model railway digital control projects.
Designed a shuttle, station start stop and digital controller and all worked well.
On the second revision of pcb's I decided to improve the noise rejection of the power supply on the digital controller.
I separated the motor driver 12 volts and the microcontroller 12 volt (pre reg) supply with diodes.
Worked on the bench ok but first customer to buy one had trouble within half an hour with motor driver IC blowing up.
So back to the drawing board. I went through motor driver datasheet again and it had a note about power supply needing to be solid to absorb flyback spikes from motor.
Of course one of the diodes now disconnected the previous capacitor and there was noise on power supply.
Luckily there was a hole in the pcb for ground near where I needed a cap and I put it in there for one leg and soldered other leg to power supply diode.
I guess the moral of the story is to think more carefully about changes and there consequences.
Designed a shuttle, station start stop and digital controller and all worked well.
On the second revision of pcb's I decided to improve the noise rejection of the power supply on the digital controller.
I separated the motor driver 12 volts and the microcontroller 12 volt (pre reg) supply with diodes.
Worked on the bench ok but first customer to buy one had trouble within half an hour with motor driver IC blowing up.
So back to the drawing board. I went through motor driver datasheet again and it had a note about power supply needing to be solid to absorb flyback spikes from motor.
Of course one of the diodes now disconnected the previous capacitor and there was noise on power supply.
Luckily there was a hole in the pcb for ground near where I needed a cap and I put it in there for one leg and soldered other leg to power supply diode.
I guess the moral of the story is to think more carefully about changes and there consequences.
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New coke! They to a great product and improved it! Don’t mess with success for the sake of updating or modernizing when no update was needed.
Conspiracy theorists say that "new coke" was a smokescreen to allow coca cola to switch from cane sugar to HFCS and still sell their product as "coke"
Sheldon
Many countries don’t allow HFCS to be used so they still have real Coke. You can get Mexican Coke in the glass bottle that is the real original sugar formula. It tastes great!
