Re: L298 goes boom on my camtronics :(

Hi Afogassa, Tauseef,

If the L298's are driving bipolar motors, I'm thinking that the bad L297
driver was attempting to turn on too many transistors in the 'H' bridge
outputs. The result is a pair of transistors in series across the motor
power supply. Something's gonna give!

Alan KM6VV


afogassa wrote:

>
> --- In CAD_CAM_EDM_DRO@y..., "tauscnc" <tauscnc@h...> 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
>
> That happened to me 4 days ago,till now I dont know why it burned
> out.after replacing just the l298 it burned out again, replace it for
> the third time and it burned again, than I replaced the l297 and it
> works fine now.
> some how the l297 was shorting out the l298.