SLA7062 and Re: New Article Posted

Jeff,

I think that most of the chips are far more subject to self-
destructing than discrete components of high current values. I
didn't expect the 7062 to be any different.

What I did expect is support after sale to determine what caused
chips to blow up when it simply wasn't due to motors shorting or
being disconnected. Just a swap from a 12v power supply to a 32v+ in
my case, and a 36v+ in the case of another customer the same week.

Without schematics, or in their absence, DETAILED and SPECIFIC
support by the vendor, it is difficult to troubleshoot when
the "dirty little secrets" of the product are concealed from the
customer. I truly believe this has been to maintain a market in
overpriced replacement chips.

Tom

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "jeffalanp" <xylotex@...>
wrote:

>
>
> Hi,
>
> >--- In CAD_CAM_EDM_DRO@yahoogroups.com, "turyga1963" <TIntruder@>
> >wrote:
> > Being that a great number of postings on the HobbyCNC group are

by

> > customers who need replacement 7062s, perhaps Dave kicked me out
> > because I disrupted a major source of income for him??? I'm
> > guessing the $3 reduction is costing him a couple hundred a

month.

> > At least.
>
> So it would appear that the SLA7062 is perhaps not as robust as

has

> been previously suggested. I guess they do go 'pop' as well, if

they

> are abused, similar to an abused A3977SED.
>
> This would most likely be to shorting of phases to one another

or

> ground, as the disconnect is generally covered by the internal

diodes

> I mentioned before.
>
> Jeff
>
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turyga1963" <TIntruder@>
> wrote:
> >
> > Greetings all,
> >
> > I have been reading all of the messages following Phil's post as
> > well as of Ballendos.
> >
> > Both have recently introduced Stepper Drivers using the SLA7062
> chip.
> >
> > I am a customer of Dave's at Hobby CNC and until about an hour

ago,

> > I was in the Yahoo Group "HobbyCNC", which requires you to be a
> > customer to join, and is the only method of getting tech support.
> >
> > By the way, Dave's boards also use the 7062 chip, and it seems

from

> > postings that Dave is insinuating that Phil and
> Ballendo/CNCResource
> > have stolen his design.
> >
> > In an attempt to learn more, I posted a question on the HobbyCNC
> > group asking Dave to discuss what he sees as the advantage of

his

> > board as opposed to these new competitors.
> >
> > I also asked if Dave was supplying boards to Ballendo, since I
> > couldn't see inside the box and if he was indeed selling to

them,

> > their complete system would be a known quality and a safe
> investment.
> >
> > I was completely respectful and asked the question in the

context

> of
> > an existing customer who is (now "WAS") willing to stick with
> > HobbyCNC even though Phil offers a pre-built solution for just a
> few
> > dollars more, and Ballendo a Plug-and-Play system at a very fair
> > price.
> >
> > In any case, with no response or reply, it appears Dave simply
> > kicked me out of the HobbyCNC group. Guess he is afraid

customers

> > will jump ship if they find out about affordable alternatives.
> >
> > I do know for a fact that Dave is not particularly committed to
> > customer service. For instance, if you blow a 7062 chip, he

sells

> > replacements for $15 (reduced to $12 just this week when I

posted

> > that CNCResource sells them for $8.50).
> >
> > Being that a great number of postings on the HobbyCNC group are

by

> > customers who need replacement 7062s, perhaps Dave kicked me out
> > because I disrupted a major source of income for him??? I'm
> > guessing the $3 reduction is costing him a couple hundred a

month.

> > At least.
> >
> > Also, if you have a problem and ask specific, intelligent and
> > reasonable questions, Dave's answer is always to "reflow your
> solder
> > connections" with no adequate answer to the specific questions.
> > Other than the assembly instructions, the only thing Dave will

tell

> > you is to reflow and set the Vref.
> >
> > He won't answer about other potential test points on the board.
> > He won't answer about ground potential issues or state whether

or

> > not optoisolation is necessary with his product even though at
> least
> > 2 people in one week had board traces burn up when connected to

a

> > PC.
> > He won't discuss failure modes or state a protocol or order of
> > accomplishing certain tasks to protect the board.
> > He has no interest in creating a FAQ.
> > Basically, if it isn't in the (meager)instructions or solvable

by

> > reflowing the solder, once he has your money, you're out of

luck.

> > Well, to be totally honest, if you ask questions he is somehow
> > incapable of answering, he might offer to buy back your board to
> > silence you, as NOT being a customer, he can turn off your group
> > membership and nobody would read about your problem with his

design.

> >
> > Note also that Dave refuses to provide schematics for his

boards.

> > Anybody who buys a HobbyCNC board is easily capable of tracing

out

> > the circuits, and with "Eagle" or similar, just by placing the
> > components and then making a few corrections on the Autorouter,

you

> > can duplicate the schematic fairly easily and make your own

board.

> > Hey, maybe some of the vulnerable "burning" traces could be

beefed

> > up this way?
> >
> > Interestingly, copyright law allows for replacement parts, or

there

> > would be no such thing as Auto Zone or NAPA. I'm wondering how
> much
> > interest there would be in replacement HobbyCNC boards?...many

have

> > burned when the SLA7062s explode.
> >
> > Based on the recent postings on this, and I suspect other

forums,

> > and the childish behavior of turning off a group membership for
> > asking respectful and appropriate questions he didn't like, I

must

> > STRONGLY RECOMMEND that if you intend to be purchase a stepper
> > driver, skip Dave and instead patronize either Phil or Ballendo,
> > depending upon how you wish to complete your system.
> >
> > Respectfully,
> >
> > Tom
> >
> >
> >
> >
> >
> >
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo" <ballendo@>
> > wrote:
> > >
> > > Dave,
> > >
> > > Sure.
> > >
> > > Sense resistor value was as suggested by Allegro app engineer.
> You
> > > probably know Matt Honji?
> > > .2 ohm for "variable" usage over the range of the device.
> > >
> > > I've used everything from .03 to .68 ohm; depends upon the use
> and
> > > motors. (not what you're using<G>)
> > >
> > > Ballendo
> > >
> > > P.S. Suggesting that folks using .2 Rs means they've copied

you

> > (at
> > > least that seems to be what you're implying about Phil? denies
> the
> > > fact that given a similar problem, and using the same device,
> > > talking to the same experts, it will be likely that some

things

> > will
> > > match.)
> > > Should we assume that you've used Dale LVR-3's because Mariss
> > does?
> > > Or simply that from the sources "typically" used by small-

scale

> > > electronics mfrs. this is the best value?
> > >
> > > BTW, we don't use the same layout, pots, caps, H/S or SIPs as
> > > HCNC...
> > >
> > > P.P.S. It's worth noting that in the new Allegro chips with
> > integral
> > > Rs, the value used is lower as the amperage goes up. Not

really a

> > > surprise; but worth paying attention to at any rate. So now a
> > repeat
> > > of my question to you: Do you have boards for yours yet?<BG>
> > >
> > >
> > > >In CCED, "Dave Rigotti" <drigotti@> wrote:
> > > >Just looked it up...
> > > >Phil purchased a 4 axis driver board from us on October 30th,
> > > >2005. This explains the same value sense resistors we use.

Not

> > > >sure what values Ballendo's version uses. Maybe he can tell

us?

> > > >Dave Rigotti
> > >
> >
>