Have i killed it?

Im using one of the 16 servo serial controller boards and i think i might of killed it.

I had it plugged into 2 servers and it was driving them just fine until suddenly it started showing all 4 leds at once.

Serial cable is fine (actually, it shows all 4 leds with nothing but the power connected).

Does this mean its passed away? or is there some magic i can work to make it come back to life?

Thanks In Advance.


I have no experience using the serial 16-servo controller, but looking through the user’s guide I see that all four LEDs will turn on if the controller is powered up with the serial input pin tied to ground. Is there a chance you have a short somewhere between your serial input and ground? This is the only thing I can think of, but someone more familiar with this product should be responding to you in the next day or so.

- Ben

I did see that, and no, according to my multi-meter it its not grounded.


All four LEDs on is an indication of your serial line staying low on power-up. How did you verify that the line isn’t grounded? (You should use the voltage mode of your meter and measure the voltage from the serial line to ground. You should see about 5 V.)

You are also asking if you killed the unit, and you said it suddenly stopped working. What happened at that point that makes you wonder if you broke it?

- Jan

Well, its actually 4.97 according to my multi-meter, but yeah there is a voltage from the serial line to the ground.

What did i do to kill the unit? nothing i know of. It was literally in the middle of a test program run and the servo’s just stopped moving and all lights went on.

By broke it i mean just died of old age really (its 2 years old roughly if i remember correctly).

Can you measure the voltage on right at the PIC pin (pin eighteen)? If you’re reading 5 V there, there’s something wrong with the PIC. If so, you can send it back to us for a replacement. If not, check continuity between the serial input pin and the PIC pin, and try to find a broken track or a short on the PC board.

- Jan

from 18 to ground its 5.

But, curiously i accidentally grounded (with the multimeter probe) the + voltage (at 6v) to the ttl serial line right next to it and the thing went from all-on to flashing yellow + solid red. Zero resistance from serial to pin 18.

Does that mean much?

“Grounding” means connecting to ground. If you’ve touched two non-ground lines together, you’ve shorted them together, not grounded them.

Can you try leaving the probe on the serial input pin of the PIC (pin 18) and making the TTL serial input high and low (without the DB9 connector connected), and see what voltages and LED patterns you get?

- Jan