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Hi, A while ago I shorted out my handy board which caused the ram chip to fry. I've since replaced it, and the board boots again, but I am now seeing other strange behaviour. The batteries are connected and the board recieves power, but when I turn (...) (25 years ago, 20-Mar-00, to lugnet.robotics.handyboard)
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| | Re: handy board troubles...
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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 (...) (25 years ago, 21-Mar-00, to lugnet.robotics.handyboard)
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| | 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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| | Re: handy board troubles...
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(...) 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 (...) (25 years ago, 21-Mar-00, to lugnet.robotics.handyboard)
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| | Re: handy board troubles...
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(...) Sorry about this, I meant 32K. John (...) completely (...) (25 years ago, 21-Mar-00, to lugnet.robotics.handyboard)
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| | 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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| | Re: handy board troubles...
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(...) Yes, that was indeed the problem. Upon removing all the ICs, the power to U14 disappeared. What could cause this, a blown fuse at F1? (25 years ago, 22-Mar-00, to lugnet.robotics.handyboard)
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| | Re: handy board troubles...
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that's possible, it's easy enough to test (just check continuity across F1). more likely that U14 croaked. is there batt pwr on its input side. f. In your message you said: (...) (25 years ago, 22-Mar-00, to lugnet.robotics.handyboard)
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| | Re: handy board troubles...
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(...) I traced the lack of power to a dead wire between C5 and pin 28 of U14; soldering a small piece of wire between these connections fixed it. Thanks, everything works perfectly now! (25 years ago, 22-Mar-00, to lugnet.robotics.handyboard)
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| | Re: handy board troubles...
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great, that's excellent! the key trick was pulling all the socketed chips. it's a weird but true fact that chips that don't have valid logic supplies can draw power in from their inputs pins (when the inputs are high) and operate off of that leeched (...) (24 years ago, 22-Mar-00, to lugnet.robotics.handyboard)
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| | Re: handy board troubles...
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This isn't technically a Handy Board problem as my code is being run on a Rug Warrior look-alike. However, I suspect that the same problem I'm experiencing would happen on my Handy Board if eviscerated one of my other robots and tried it. (...) (24 years ago, 15-Apr-00, to lugnet.robotics.handyboard)
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| | Re: handy board troubles...
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gary -- it's an interesting bug. as you say you've got two 2-dim arrays, i can surmise that you're using Newton Lab's version of IC. In which case, they'd be the ones to address this problem. re: mailing list, it's now administered through LUGNET. (...) (24 years ago, 16-Apr-00, to lugnet.robotics.handyboard)
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