Re: board repair

Hi Dan,

Thanks for the info. Looks like this time lucky. It was most probably
the 7812 used to suppy the 12-18VDC that was the problem. It was used
without a heatsink. Changing a new 7812 plus a heatsink gave a nice
yellow and green glow to your board. (BTW am I too near the 12 of the
12-18VDC requirement of the logic circuit?)

However using MDI to try to move the stepper resulted in deadly
silence. However, thanks to you kindly providing a nice spot for us
to place our VOM probe I can now do some "nice" trouble-shooting
(Gecko shouuld provide this feature). While the computer was spitting
out step signal, Vref remained at the holding reference voltage of
0.25. I think most likely the stepping signal are not reaching the
driver? Probably the lousy slapped-together I am using or I got the
pinouts wrong. Will look into that afterwards.

Now looking for a website where one can learn trouble-shooting. Any
list members have a website with that?

Thanks in advance

Keongsan

--- In CAD_CAM_EDM_DRO@y..., "Dan Mauch" <dmauch@s...> wrote:
> If you reversed just the connections to the motor terminal block
then
> you probably just blew the L298. If however you connected the power
> leads to the Logic side at J7 backwards, then you probably toasted
the
> 4066, the 74hct123 and ds11233 and the l297.
> Dan
>
> -----Original Message-----
> From: keongsan [mailto:keongsan@y...]
> Sent: Monday, April 22, 2002 9:11 PM
> To: CAD_CAM_EDM_DRO@y...
> Subject: [CAD_CAM_EDM_DRO] board repair
>
> Hi all,
>
> I have inherited a camtronics 2A driver board, a very nice board.
> Wish I can have more of them.
>
> Now I have a small problem (and a nice opportunity to learn board
> repair) which I hope some electronics enthusiast/camtronic owner on
> the list can provide some helpful pointer.
>
> I may have reversed the polarity to the motor power supply. Now
when
> I apply the 12-18VDC to the logic side, the LED's does not light up.
>
> I want to know what components of the driver board are most likely
to
> take a rest when the motor power supply polarity is reversed?
>
> Thanking you in advance
>
> Keongsan
>
>
>
>
>
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