Subject:
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Re: Handyboard assembly problem fixed
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Thu, 7 Mar 1996 22:50:32 GMT
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Original-From:
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Ramasubramanian, M. K. <rammk@eos.ncsu.edu&AvoidSpam&>
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Viewed:
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2177 times
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Dear Fred:
No, we went through the assembly following your directions step by step. By
the statement " Board OK", I meant that the tests upto the point of
downloading pcode (second time with LCD in) tested OK. I did not want to
bore the audience with all the details, as you have them spelt out very
clearly in your documentation. We checked the serial line
circuitry(downloading pcode without the memory chip), microporcessor and
oscillator circuitry(2MHZ square wave), and the memory circuitry (Voltage at
pin 28).
After installing the Beeper and the LCD, the download was succesful, but the
board will not come up display the IC banner. I changed the memory chip with
a spare one and I had the same problem. I plugged in the memory chip into
another handyboard and it worked fine. So it was not the memory chip. At
this point, I could not think of other ideas to isolate the problem any
further and I sent my email for help.
I hope I have provided enough details now.
HOWEVER, the problem is fixed. Prabal suggested reheating the memory solder
joints and that did it. I must have had a bad solder joint at one of the
pins. My suspicion is pin number 22 from close visual inspection before
heating.
Thanks to Prabal, Now we have the entire board up and running fine.
Regards
Here's verbatim response from Prabal to my problem.
I have not run into the exact problem which you describe, but I have
some ideas which may be beneficial anyway. The first thing I would check is
to make sure all the RAM pins are soldered properly. Since DL downloads the
code without problems, the 6811 is probably working fine. However, it may
be unable to run the pcode if it can't access the RAM. Even if all the pins
are soldered fine, try reheating the joints. If that doesn't work, look for
the same symptoms with the 373 chip mounted under the RAM and finally check
the 6811 itself. Other silly thoughts: did you mount the 373 and RAM in
properly? Hopefully that will help. If not, perhaps somebody else might
have some suggestions. Good Luck!
- Prabal
Thanks for your response.
Ram.
Ah, the classic "I built it and it doesn't work" story.
>
> Did you follow the incremental building instructions? I take it the
> answer is no.
>
> My suggestion is to pull all of the chips, and run through the series
> of incremental tests in the building instructions in order to isolate
> the problem. Also, I am a little puzzled by your statement "the board
> checks out OK"; exactly what part of the board does check out? Other
> than the oscillator.
>
> -Fred
>
> --
> This message was composed using Articulate Systems' PowerSecretary,
> a Macintosh-based speech-to-text dictation system.
> Please forgive any sloppiness in the formatting. Thanks. -Fred
>
>
>
> In your message you said:
> > We have assembled our fifth handyboard and have run into the following
> > problem. (The other four boards went smoothly). The command dl pcode_hb.s19
> > downloads fine just as it did on the four other boards that we have built.
> >
> > However, when I power cycle the board, I do not get the familiar Interactive
> > C and the heart beat monitor. The LCD panel is dim, just as it was in the
> > bootstrap mode and the power light (green) is on.
> >
> > The board checks out OK, the oscillator is working fine.
> >
> > When I hookup other handyboards, everyting goes smoothly with the same
> > charger and wires that I have setup.
> >
> > Does anyone have suggestions how I might proceed further in troubleshooting
> > this problem?
> >
> > Thanks for your time.
> >
> >
> > Ram
> > -----------------------------------------------------------------Dr. M. K.
> > Ramasubramanian
> > Assistant Professor
> > Department of Mechanical & Aerospace Engineering
> > North Carolina State University
> > Box 7910
> > Raleigh, NC 27695-7910
> >
> > (919)515-5268
> > (919)515-7968 (Fax)
> > rammk@eos.ncsu.edu
> >
> >
>
>
-----------------------------------------------------------------Dr. M. K.
Ramasubramanian
Assistant Professor
Department of Mechanical & Aerospace Engineering
North Carolina State University
Box 7910
Raleigh, NC 27695-7910
(919)515-5268
(919)515-7968 (Fax)
rammk@eos.ncsu.edu
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