[time-nuts] Fluke monitor
didier at cox.net
Wed May 12 21:09:44 UTC 2010
Must be the Y2.01K bug...
Sorry about the problems being reported recently.
While I have no association with Bob of Fluke.l, he is using my design and he was kind enough to send me one demo model, which I have yet to turn on.
In general, if the processor is not fried, there is very little that can go wrong:
1) check that the serial data getting to the processor is clean. Noise on these lines in unforgiving since the protocol has no error detection or correction. In my design, I use a single bipolar transistor to convert the RS-232 to TTL. Not the best way to do it if noise is a concern. It works fine for me, but YMMV....
2) check the interface to the LCD. There are 7 wires in addition to ground and +5V. An intermittent connection with cause trouble.
3) check the supply voltage. Most regulators should work fine with 7V input, more voltage only makes more heat. With an LCD display, the current consumption should be low (20 to 50mA) and relatively constant, mostly a function of the backlight. With a VFD display, the consumption is quite a bit higher (several hundred mA) and fluctuates depending on how many segments (pixels) are turned on.
---- msproul <msproul at suddenlink.net> wrote:
> >My fluke.l monitor stopped working today ...
> Mine stopped yesterday
> >The monitor is a recent model and has the regulator.
> So does mine and I run the board from a 9V regulator.
> The display is built into the same box as the gpsdo
> >I left it on overnight,
> Mine has been on continuously for over a month
> >The backlight is fine and the display works.
> >.... and occasionally gives garbled displays of other data.
> >.... alternating between ... some data or other every few minutes,
> >but the data doesn't appear to be accurate.......including question
> >marks in numeric fields,
> Same thing here
> Other errors that I get :
> 2 lines of date & time
> Only one line of date & time on the display
> It has frozen displaying only one line of date & time for several minutes
> Sometimes displays "TSIP LED Monit"
> Ocassionally only the back-light is on, nothing displayed
> This lasts for a couple minutes then resumes "normal" display.
> There seems to be a pattern developing. Is this an inherent problem
> with the processor board or with the software? All together, mine has been in
> operation about 3 months which would seem to rule out a software problem.
> The occasional display of "TSIP LED Monit" would indicate that the processor
> is being reset as this is normally seen at power-up.
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