Re: [CAD_CAM_EDM_DRO] L298 goes boom on my camtronics :(

Taus,
Arrrrrhhhhhhhgggg!
You broke rule number one!
NEVER disconnect stepper windings with drive power applied.
The high voltage back EMF is a killer to the IC's.
If you want to disable use the supplied AWO (all windings off) feature.
Jumper J8. That's what it's there for.
OK?
RichD

tauscnc wrote:

>
> well well well, how are you? Me, smelling a little smoke :( I was
> connecting a simple switch to J4 and J8 so I can "free" my motors
> without having to turn off the main power on my Camtronics 2A 3 axis
> board and single board all the time.
>
> Well I thought if I connect J4 (single axis) it frees the A axis. If
> I connect J8, it frees XYZ axis. So what I did was to install one
> switch for both boards. I connected a wire from one pin of J4 to one
> pin on J8, other pin on J4 to the other pin on J8..I then connected
> two wires from J8 to a switch. Switch off and I pluged it in, ZAP!
>
> my power fuse blew. I looked it all over and and undid the J4 wires,
> ZAP 2nd time, I undid all of them ZAP 3rd time.
>
> I then spun the motors by hand and ALL 4 AXIS motors felt very
> gritty,, like they where shorted out or had some "holding power on"
> (remember no power is on)!
>
> I was so scared I pulled everything apart hoping it was the power
> supply but it works fine. Intersting is that NONE of the axis fuses
> blew, just the main power fuse.
>
> Looking around I noticed the L298N cracked on the single board!!!!
> Got real close and I could smell it a little. Y axes seems to be the
> worst where the motor almost seems like it has holding power, very
> gritty to turn (each motor is free when not connected). Well I hope
> it's only the 4 L298 that need replacing. Found a price for them but
> waiting on Dans responce first.
>
> Pic included of the single axis L298 if you care to share in my
> depression :(
>
> http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/Tauseef%27s%20CNC%
> 20Sherline%20/L298-Camtronicboom.JPG
>
> (its under files and "tauseef cnc sherline"
>
> tauseef
>
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