mitel 5340e IP Phones LCD display washed out

[bob2246]

I've had issues with several of our 5340e IP phone displays "washing out"; the display appears to fade to a point where it is barely readable.  On the first phones that exhibited the problem, we went into the phone settings and increased the contrast, which made them somewhat readable again.  But at that point the contrast was maxed out, so subsequent recurrences of the issue left us with nothing to do other than replace the phone with a spare.

I sent two phones that exhibited this problem to our vendor, but when he got them a couple of days later and powered them up, they appeared to function normally; their contrast was back to where it should be.

Has anyone else seen this problem?  Does anyone have a solution?

Thanks in advance...

[acejavelin]

Any magnetic fields in the area? These are Liquid Crystal Displays and are subject to magnetic fields, we have seen in a few instances like near large transformers, any vicinity of MRI machines, close proximity to some poorly shielded tube displays, etc. Remove them and let them sit for a few days and often back to normal. Sounds very much like what you have experienced.

[bob2246]

No, no magnetic fields.

I'm fairly certain that the display on this phone has just failed.  I returned it to my vendor, and it plus some cash will get me another, most likely refurbished, unit.

I went though the several spares that I have, and found two that I'd rotated out for the washed out screen problem.  However, when these two powered up, after the initial splash screen, the screens went very dark.  This happened, I'm guessing, because they'd exhibited the wash out problem, and the users cranked the contrast to its maximum to make them readable.  I was able to restore them to readable by decreasing the contrast to mid-range.

When they exhibited the problem, I tried unplugging then immediately re-plugging to power cycle them, but they always returned with the washed-out display.  So, I rotated them out with spares I had, and left them sit on a shelf.  Now, they're fine.  Not sure what to pin that to, but I felt the details would be worth sharing.

[demery]

I too have the same issue with my Mitel 5340e IP phones and the 5330 phones exhibit the same behavior.  I am starting to wonder if the problem is more a bad component on the mainboard such as a capacitor because this issue is similar to what would happen to an old Gamegear console where the capacitors go bad and you cannot control the contrast on the screen anymore.  I'm hoping to figure out what component is failing so I can purchase the electronic component to be able to fix them myself rather than going though the long hassle of RMAing the phones though our vendor.

Key note on the handset issue where if you slowly pickup the handset the spring may not be able to get the button pushed to turn on the phone for answering. Tensioning the hookflash spring sometimes can fix it but my latest phone was unfixable by adding tension to that spring.  I tried another option where I took a Q-tip and cleaned the circuit board at the spot that the answer button presses and the electrical contact pad.  Key note don't clean to hard on the rubber contact pad because there is a substance on it that makes the electrical connection and you don't want to wash that off to much.  I just gave it just a slight cleaning and you can see a little black come off onto the Q-tip.  After reassembling the phone it was working perfectly again.

[demery]

Small Update,

I did a test where I swapped screens with a known good phone and the washed out screen problem follows the main board in the phone and not the screen it's self.  This is sort of good news as changing screens on these phones is a pain.  I still have not been able to identify any component that could be causing this issue.  If anybody is good at electronics repair it would be good to hear from them on this issue.

[lordheetsink]

I see this alot on 5320e phones in my location. I can adjust brightness and contrast to bring it back. I wonder if users are doing this, or its a bad setting in the screen saver setting.

[bob2246]

I have tried adjusting the contrast and brightness, but after awhile the display dims to the point of no recovery.