One of the Infoglobe I have, started to have problems time ago.
Initially the problem was random, one row of the message, was missing for few seconds, then working normally.
But on time, the missing row problem become permanent.
Then another row started to dim and then disappeared.
At this point I decided to open the Infoglobe and discover the cause of the problem.
Here a description of what I did, hopefully it can be useful to somebody else.
Opening the Infoglobe
As described in my first article on the Infoglobe, I opened the Infoglobe.
However, I just removed the dome. There is no need to remove the 4 screws on the bottom since the problem is located only on the rotating arm.
Once removed the dome and unscrewed the rotating arm, I removed the rotating arm for a detailed inspection.
|The rotating arm removed from the Infoglobe|
The rotating arm is composed by two PCBs connected at 90 degrees.
The small PCB at the end of the arm is hosting 8 LEDs (in my case, 8 blue LEDs).
In the picture, note the arrows indicating the side exposed during the rotation.
The first thing I noticed was a dark color on the side exposed in the rotation.
I think is was dust mixed to small PCB particles. The high rotation and vibration, during the years, probably caused a partial disintegration of the PCB and conductive material.
The rotation itself allowed this dust, probably also electrically charged, to deposit on the LEDs side exposed to the rotation.
Note in the picture above the dust deposit around the LED. When the dust touched two LEDs, a short circuit happened, forcing the LED off.
Initially only for few microseconds, thus the "dimming" effect, then with enough dust, permanently.
Fixing the problem
With a very soft old tootbrush, I removed the dust from the rotating arm, especially from the PCB with the LEDs, and then I put it back the rotating arm.
It worked perfectly.
I was worried to have to re-do some soldering on the LEDs, but I didn't found any sign of detachment, so for the moment I put it back the rotating arm and close the dome again.