[time-nuts] Fluke monitor
Leigh L. Klotz, Jr WA5ZNU
Leigh at WA5ZNU.org
Mon May 17 05:12:33 UTC 2010
You're right about the current. I just checked it with my DMM and got
45ma. My inline power meter must not be that it's not that accurate at
the low end.
The display works; the backlight works; the processor must be doing
something since it prints a variety of messages. It's the RS232 that
has flakey. The hardest thing at this point is to unsolder the 16-pin
header. Bob suggests that a 12v regulator may have failed.
> In a message dated 12/05/2010 17:45:16 GMT Daylight Time, Leigh at WA5ZNU.org
> The monitor is a recent model and has the regulator. I left it on
> overnight, in its original case and out in the open, hooked to a 13.5V
> supply. I had it on a ammeter the whole time, and it never draws more
> than 0.02A. The backlight is fine and the display works.
> Something doesn't seem right with that current consumption.
> Mine's not in use at the moment, as my test area is still stripped down,
> but when it was I measured a consistent 47mA once the regulator had a high
> enough supply to ensure it was regulating, in my case I was using 12 volts
> but the current is determined by the regulator output voltage so shouldn't
> vary much anyway.
> The display is what was fitted originally fitted to the iCruze module but
> the processor board has been changed so that Didier's Tbolt Monitor code can
> be used.
> The processor module circuit is pretty basic so I wouldn't have thought
> there was too much room for a design error.
> I'd be inclined to start by separating the processor board from the
> display and then reconnect using a temporary link of flexible wiring so as to be
> able to check if the processor circuitry is actually drawing current, then
> I'd probably continue by looking for quality issues, bad joints, solder
> bridges, etc.
> If that turned up nothing obvious then a more in depth examination of what
> the processor is doing would be my next step, in particular it would be
> interesting to know how it's handling the RS232 interfacing just in case it's
> a comms issue.
> Given that Didier's code is freely available, and the processor board
> schematic is easily traced, it shouldn't be too difficult as a last resort just
> to build a replacement.
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