View Full Version : Frying servos with the Servo Controller. Please Help!

Death Wraith
01-15-2006, 09:51 AM
I'm just trying to get my PSC(usb version)·up and running but something is wrong. I'm using a regulated 'wal-wart' at 5VDC and 2.0A as the power supply for the servos. I cut off the plug and hooked up what I thought was the positive wire (ribbed with lettering on it) to the + terminal and the other wire (smooth no writing) to the negative. Opened up the usb software which recognized the PSC just fine. Hooked up a Parallax continuos rotation servo, turned on the power button but it wouldn't move when I used the slider on the software. Within a few seconds smoke started pouring out of the case! So I tried reversing my cords, plugging in the ribbed wire to the negative and the smooth to the positive. Hooked up a Hitech 425bb servo and tried to move it with the software. No response and the bottom of the servo case got really hot. I got it turned off before any serious damage I hope.

I can't afford to lose any more servos just testing trying to find the problem. Can anyone help?

PJ Allen
01-15-2006, 10:35 AM
Do you have a voltmeter?

Death Wraith
01-15-2006, 10:38 AM
Not yet.

Beau Schwabe (Parallax)
01-15-2006, 10:42 AM
I would suspect that your original problem was not knowing for sure which was positive and which was negative from your
'wal wart'. Now, since you have let some of the smoke out, it is hard to say what condition things are in. Do you have a
voltage meter that you can use to test the proper polarity? ....If not you could always stick the leads in a cup of water with
a pinch of salt. The negative terminal will start to bubble before the positive terminal becomes noticeable.http://forums.parallax.com/images/smilies/smilewinkgrin.gif

BTW) I recommend a voltage meter of some kind, be it analog or digital.

Beau Schwabe (mailto:bschwabe@parallax.com)

IC Layout Engineer
Parallax, Inc.

PJ Allen
01-15-2006, 10:44 AM
I stopped making assumptions about ribbing and stripes and all that a long time ago --·a rib or a stripe on a wire mean that the wire has a rib or a stripe, but the voltmeter removes all doubt.· I'm not trying to give you a hard time, you need to get a voltmeter, that's the only way to know what's what.·

Death Wraith
01-15-2006, 10:53 AM
I do appreciate the advice and no offense taken. We all were newbies once upon a time. I'm just a little late coming to the game. I have a multimeter on the way from All Electronics which should help me sort out what's what. Any other suggestions/advice?

01-15-2006, 11:48 AM
you might try using an LED if you have one...they are alot cheaper to smoke than a servo.