A real head-scratcher

Jay Honeck wrote:
[JPI EDM-700 engine analyzer missing seven-segment display segments]

Now for the odd part: The missing segments of the LEDs are NOT
consistent. For example, the same section of LEDs might improperly
display an "8" with a couple of missing segments on the right side of
the 8 -- but the next second it will change to a "9" and those right-
side segments will appear normally!

Disclaimer: This is based on experience with ground vehicles and
equipment. I don't have an A&P; I don't even have a TG&Y. Your mileage
may vary.

I'm going to add my vote for a bad connection or cold solder joint
internal to the analyzer.

The time-honored diagnostic is to thwack it with your finger and see
if the display changes.

If you're feeling adventurous, temperature-cycle it to see if the
display changes. Like: go to the hangar at 6 AM after the plane has
been sitting all night, turn on the master, and check the display.
Then, put your calibrated fingertip next to the display, and very
carefully direct a hair dryer (on low) at the display to see if it
changes. If your finger gets too hot for comfort, shut off the hair
dryer.

It's not _impossible_ for the internal programming to change on its own,
but it's highly _improbable_.

Disclaimer: This is based on experience with ground vehicles and
equipment. I don't have an A&P; I don't even have a TG&Y. Your mileage
may vary.

Matt Roberds

wrote:

The time-honored diagnostic is to thwack it with your finger and see
if the display changes.


If that fails, try time-honored diagnostic #2: unplug the unit and plug it
back in to reseat the connectors.

--
Dan
T-182T at BFM

The time-honored diagnostic is to thwack it with your finger and see
if the display changes.

If that fails, try time-honored diagnostic #2: unplug the unit and plug it
back in to reseat the connectors.

Well, I've tried whacking it (of course!), to no avail.

Luckily, my next planned upgrade was to install the outside air
temperature probe for the EDM-700, which will mean pulling the unit
out of the panel anyway. It's a real SOB to get at, so I suppose I
should be thankful that it chose now to go screwy...

Once it's out, we can play with it a bit more. I'm betting that I
have to send the danged thing back to JPI...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

At least, then you'll get the latest software................which is a big
improvement i've been told



KG


"Jay Honeck" wrote in message
ups.com...
The time-honored diagnostic is to thwack it with your finger and see
if the display changes.

If that fails, try time-honored diagnostic #2: unplug the unit and plug
it
back in to reseat the connectors.

Well, I've tried whacking it (of course!), to no avail.

Luckily, my next planned upgrade was to install the outside air
temperature probe for the EDM-700, which will mean pulling the unit
out of the panel anyway. It's a real SOB to get at, so I suppose I
should be thankful that it chose now to go screwy...

Once it's out, we can play with it a bit more. I'm betting that I
have to send the danged thing back to JPI...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

On Sep 4, 1:23 pm, "Dan Luke" wrote:
wrote:

The time-honored diagnostic is to thwack it with your finger and see
if the display changes.

If that fails, try time-honored diagnostic #2: unplug the unit and plug it
back in to reseat the connectors.

The EDM is a single unit, the display and internals are one piece so
there really isn't anything to unplug and replug in other than the
actual probes, which doesn't appear to be related to the problem.

-Robert