Subject:
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Re: handy board troubles...
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 21 Mar 2000 21:46:59 GMT
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Viewed:
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1307 times
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In lugnet.robotics.handyboard, Jake Burkholder writes:
> In lugnet.robotics.handyboard, John Wynne writes:
> > Actually Jake, I'm having a similar problem right now, with regard to
> > loss of RAM capabilities.
> >
> > I've been testing a new Polaroid 6500 sonar (which now works!) on the HB
> > and I've got it hooked up through the exp. board. I tried to run a simple
Yes! I apologize, I meant "..._without_ the RJ11 cord connected..."
Is it possible a surge could have fried the RAM and now it won't
hold memory? That was my contention, but I'm not sure...
John
p.s. RAM replacement question: Will any 64K CMOS SRAM 28 pin chip work?
I have a HM6264P-12 120ns RAM chip that I bought today, and was wondering if
I might expect problems (due to difference from the recommended RAM chip)...
Thanks!
> > program that used actuated two servos, two motors, while polling one analog
> > input. It seemed to work without the Polaroid connected, but when I fired
> > it up with everything loaded on, it died, and now my HB can't seem to hold
> > it's RAM with the RJ11 cord connected to the charger/dler. I'm not completely
> ^^^^
> Do you mean without? That's my problem; the board only holds its data if
> the cord is plugged in.
>
> > sure how the servos are powered/oscillated (etc.) so I haven't been able
> > to locate where I might have suffered some kind of power surge (possibly
> > from the sonar ranging board)... does it make any sense to think that
> > the sonar could have any affect on other periferals without being directly
> > powered up?... How ARE the servos on the Exp. Board driven?
>
> I've also got a servo which I can't figure out how to drive from the
> exp. board, but the problem of the RAM discharging happens even with a
> bare board (no exp., no lcd).
>
> I'm convinced its a voltage problem and was going to try replacing the fuse
> at F1 next.
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Message has 2 Replies:
 | | Re: handy board troubles...
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| re: this problem with the memory contents not persisting, check the separate power supply to the RAM (U14). you might need to remove all socketed ICs from the board 'cause power can bleed to chips via input pins. also check that U12 the DS1233 is (...) (25 years ago, 21-Mar-00, to lugnet.robotics.handyboard)
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Message is in Reply To:
| | Re: handy board troubles...
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| (...) ^^^^ Do you mean without? That's my problem; the board only holds its data if the cord is plugged in. (...) I've also got a servo which I can't figure out how to drive from the exp. board, but the problem of the RAM discharging happens even (...) (25 years ago, 21-Mar-00, to lugnet.robotics.handyboard)
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