I have serviced a few of these already. One was mine, right out of the box.
In my case, one LED at the extreme range of travel would not light
sometimes.
All it required was a touch up of solder on one of the terminals on the back
of the bar display, inside the unit.
The other one was in someone else's plane, with quite a few hours. The
symptom was that the two LED's (segment lights) in the middle would not
light up. These two segments corresponded with cruise settings. I was sure
that it was the dot/bar driver IC inside. On further inspection, it turned
out to be that the two LED's on the lighted display were blown and the
Integrated circuit was just fine. Most LED's should last 100,000 hours.
WOW, that was a stunner! (it could be that they are driven at high current
levels, for maximum brightness in the cockpit on sunny days..but I did not
check) Thus in this case, a new $2 10-segment Light display was called for.
>From Jeff R's symptoms:
I am almost positive that based on the intermittent symptoms in Gold Rush,
it will just require a solder touch-up inside the display unit. Cost: about
1 cent worth of solder.
In the other two cases, there is not enough info to go on. If the LED's
sometimes still work (from hand tapping), it is probably a solder Job. Tap
on the display unit while it is operating, to see if you can get all of the
LED's to come on. Once is enough, even if only a split second. It verifies
the LED (Light Emitting Diode) is not burned out.
An intermittent problem in flight that is not resolved by tapping on the
display, could also reside in the position feedback inside the servo itself,
back on the rear bulkhead, though I have as yet to see that failure.
It is quite a simple circuit inside these display units. I used to play with
the exact same circuit on a solder-less breadboard...way back in High
School. In fact, I built a display for my Ford Pinto to verify the voltage
in the car, just for fun. A cassette tape holder served as the case for it.
If memory serves, it fell out of its berth and onto the floor when the car
got rear-ended...
Regards,
Greg Fuchs, A050
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