Roger, my apologies. I missed that little rascal. What a crook way to go
about circuit design. That could make the whole system more vulnerable to
RFI as well I think.



----- Original Message -----
Sent: Monday, November 03, 2003 4:35 AM
Subject: [M]: Re: Electrical question


> > Michel, as long as you keep your two car batteries connected in
> > parallel ie. positive to positive, negative to negative you have
> > nothing to fear. The converter to your laptop will supply the
> > laptop needs; and any voltages that occur on the port pins will
> > be correct and referenced to the "same "ground as is every other
> > device you are using. Even if you isolate the batteries there is
> > little chance of a 'cookout' however strapping the two batteries
> > together forces all to have the same ground reference. And if you
> > were to power your LX200 from the mains converter you could still
> > tie your (one) battery ground to the scope/fork ground as this would
> > ensure a perfect ground reference. Just remember that the negative
> > terminal of your battery is your ground reference.
> > Doug
> NO!...
> Do _not_ do this. You risk damaging the equipment.
> The 'key' is to understand that the LX200, does not use battery negative
as
> it's 'ground' reference. It has a sense resistor (used to feed the display
> showing the current drawn), between the -ve connection, and the 'ground'
> connection on the RS232 plug, and the CCD plug. If you join the
battery -ve
> connections, and attach an un-isolated device to one of these ports, you
> risk the power being drawn through this connection, rather than through
the
> power connection. This is how you can blow the RS232 port, or the guide
> system...
> This is the big 'LX200 caveat', when wiring.
>
> Best Wishes
>
>
> ----- Original Message -----
> From: M. Bonnardeau
> Sent: Sunday, November 02, 2003 8:34 PM
> Subject: [M]: Electrical question
>
>
> I use to power my LX200 Classic from a 12V car battery (without the
12-18V
> converter, it's an 8") and my laptop computer from another 12V car battery
> (with a converter). The scope and laptop are connected via the RS232 line.
>
> I also have a SBIG ST7 camera powered from the battery to power the
scope.
> And the camera is connected to the scope for autoguiding and to the laptop
> via the parallel line.
>
> So far nothing has fried. But considering the scary electrical design of
> the LX reported in the archives, I am having doubt about my connections. I
> would be very grateful for your comment about it.
>
> Michel
>
>
>

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